2: Developmental Disturbances

Developmental Disturbances

Identification of normal anatomical structures forms the basis for diagnosis. The skill and knowledge to differentiate normal from abnormal plays a decisive role in effective management of the disease process. It is a known fact that normal anatomic structures can have various clinical presentations within the same species.

However, one should realize that even the slightest of change in the appearance of the structure of organs and tissues makes the recognition of pathological conditions challenging. On the other hand, normal oral anatomic structures can induce cancerophobia in many individuals. These individuals have to be educated regarding the absolutely benign nature of these anatomical variations.

Fordyce’s Granules (Fordyce’s Spots/Disease)

Fordyce’s granules are named after an American dermatologist, John Addison Fordyce. This is an ectopic/heterotopic collection of sebaceous glands seen in more than 80% of the normal population.

They are considered ectopic because sebaceous glands are typically appendages of the skin. When they are present in the oral mucosa they seldom have hair follicles.

This condition is characterized by the presence of multiple discrete minute yellow colored ‘dots’, ‘spots’ or ‘granules’ involving various sites in the oral cavity such as the buccal mucosa (opposite the molar teeth), lips, oral commissures, retromolar pad, faucial pillars and the palate (Figure 1). Some authors have described the appearance as ‘rice-like’, white or yellow white papules. The sebum produced by these sebaceous glands imparts the yellow color to these spots. Each of these granules can vary in size from 1 to 3 mm. The condition is asymptomatic and usually prominent in adults and generally persist throughout life.

Histopathologically acinar lobules are seen below the surface epithelium. These acinar lobules usually communicate with the epithelial surface via a central duct (Figure 2). The ducts may show keratin plugging. The sebaceous cells are roughly polygonal in shape with a central nucleus. The cells contain copious amounts of foamy cytoplasm.

Unless these granules are esthetically disturbing in an individual, no surgical intervention is recommended. Patient should be educated regarding the harmless and persistent nature of the condition. Ocampo-Candiani et al (2003) showed that CO2 superpulsed laser can be used as an effective treatment modality for patients who desire treatment for cosmetic reasons. Sebaceous gland adenoma may occur at times.

Lingual Tonsils

Lingual tonsils are the lymphoid aggregates present in the oral cavity that are part of the Waldeyer’s ring. It can occur unilaterally or bilaterally on the posterolateral border of the base of the tongue. Lymphoid follicles of the lingual tonsil are irregular in shape and size and vary in number from 30 to 100.

Anatomically, the arterial supply to the lingual tonsils is via the lingual branches of the external carotid arteries. The venous drainage is through the lingual vein that finally empties into the internal jugular vein. The lingual tonsils are mainly innervated by the lingual branch of the glossopharyngeal nerve and to some extent from the superior laryngeal branch of the vagus nerve.

Lymphatic vessels of the lingual tonsil drain into the superior deep cervical or jugular lymph nodes.

The lingual tonsil is generally not evident on routine clinical examination. It may appear as solitary pink colored papule or nodule with a glossy yellowish-pink surface. However, it becomes clinically evident when inflamed and enlarged. Persistent inflammation of these tonsils has also been referred to as lingual tonsillitis. Lingual tonsillitis which is a painful condition characterized by the symptoms of sore throat and cough. The tonsils are erythematous and spongy or soft on palpation, mimicking lesions of erythroplakia or oral cancer. However, the bilateral presence of these nodules will help in differentiating it from carcinoma.

Lingual tonsils do not require any active management. The patient should be reassured and told to report any change in size or presence of symptoms. Lingual tonsillitis can be managed with antibiotics. Extensive enlargement of the lymphoid aggregates can impede intubation. Histopathological evaluation is advised when the lymphoid aggregate enlarges rapidly in size or exhibits surface ulceration.

Fissured Tongue

Fissured tongue has been described by various names in literature such as scrotal tongue or lingua scrotalis, lingua plicata, lingua fissurata, cerebriform tongue and furrowed tongue. The tongue in this relatively common malformation exhibits multiple grooves or furrows of 2–6 mm depth and varied pattern on the dorsal surface. Heredity, aging, chronic trauma and vitamin deficiency have been proposed as the causes for this condition.

The exact etiology for this condition is still unknown. However, a polygenic mode of inheritance is suspected because it is seen clustering in families who are affected. Based on the geographic location and population studies, the prevalence of fissured tongue ranges from about 2% to 21%. Males are said to be slightly more predisposed to exhibiting this condition.

The fissures are seen on the dorsal surface of the tongue sometimes extending to the lateral margins. The fissures can have various morphological patterns; a single prominent groove in the midline of the tongue, multiple horizontal groves radiating from the median groove and multiple grooves in an irregular fashion (Figure 3A, B).

The tongue fissures can be seen in childhood. However, the fissures are usually prominent with advancing age. Fissured tongue is usually associated with other conditions such as geographic tongue (see Figure 21), Melkersson-Rosenthal syndrome and Down syndrome.

The condition is generally asymptomatic. However, the deep fissures provide an excellent site for lodgment of food debris and candidal colonization. These patients may complain of burning sensation in the tongue.

Leukoedema

Leukoedema is a common alteration of the oral mucosa, which appears as a diffuse grayish white opalescent area on the oral mucosa. It is believed that the intercellular edema of the superficial epithelial cells and the parakeratinized epithelium produces the typical grayish white appearance in this condition.

Axell et al (1981) studied the influence of tobacco habits and leukoedema among 20,333 individuals in Sweden. In his study 48.9% of the individuals exhibited leukoedema. Males were more commonly affected. Leukoedema was more commonly found in the second and third decades of life. The condition was significantly more prevalent in individuals with any form of tobacco habit (60%) and relatively less common in individuals without any tobacco habit (36.3%).

Van Wyk (1985) studied the association between leukoedema and smoking. He examined 1996 high school students. He concluded that smoking does not cause leukoedema but may aggravate it. He also suggested that the etiology for leukoedema is multifactorial.

Histopathology and ultrastructural features

Histopathological studies reveal increased epithelial thickness. Parakeratinized epithelium with broad and elongated rete pegs are typically seen. Intracellular edema within the spinous layer is a characteristic feature in leukoedema. The edematous/vacuolated cells are large with a pyknotic nuclei. Histopathologically it is believed to mimic lesions of white sponge nevus.

Van Wyk and Ambrosio (1983) studied the ultrastructural and histochemical features of leukoedema in 12 individuals and compared it with normal buccal mucosa. They concluded that the ‘intracellular edema’ of the epithelial cells in leukoedema is due to vacuolation in the cytoplasm of cells. Toward the surface of the epithelium, the vacuo-lated cells collapsed into a compact layer of flattened cells. The outer cells of this layer abruptly swelled again to form the characteristic superficial layer of ‘ballooning’ cells of leukoedema.

They proposed that the vacuolation in the cell cytoplasm represents a reversible form of cellular degeneration resulting from cell damage. They believed that the vacu-olation was caused because of reduced mitochondrial function. The superficial ‘ballooning’ cells are degenerated cells. They stated that the presence of a compact layer of vacuolated cells, keratohyalin granules and keratohyalin-like structures in the superficial cells are features of an aborted form of keratinization.

Retrocuspid Papillae

The retrocuspid papilla is a normal variation in anatomy characterized by the presence of pink colored, soft to firm, generally sessile papule or nodule (Figure 5), located on the gingiva on the lingual surface of the mandibular canines (cuspid).

The size of the nodule may vary in size from 1 to 5 mm in diameter. It is very commonly seen in children and believed to regress with age.

D’Aoust et al (1991) studied the distribution of retrocus-pid papillae among three groups (Ecuador, Honduras and Nicaragua) of Latin American patients. He found that the retrocuspid papilla was most prevalent in children below the age of 5 years. He also found a significantly higher female predilection in the Honduras group of Latin Americans and unilateral presentation was more common. Bilateral presence of retrocuspid papillae was seen in the Nicaragua group. Retrocuspid papilla was seen involving the attached gingiva more frequently than the free marginal gingiva. Brannon et al (2003) also showed that retrocuspid papillae are common in females and young children. In the 51 cases that were evaluated, bilateral retrocuspid papillae was more common.

Histological features

Buchner et al (1990), histopathologically analyzed 30 specimens of retrocuspid papillae. They showed that almost 80% of the specimens showed loosely arranged delicate fibrous connective tissue with stellate and multinucleated fibroblasts. They also showed that significant number of specimens exhibited elongated rete ridges and/or increased vascularity.

These papillae do not require any form of treatment. The need for treatment may arise only during the fabrication of prosthetic appliances.

Prominent Palatal Rugae

Palatal rugae have also been referred to as rugae palatinae and plicae palatinae transversae.

The word ruga (plural: rugae) is a Latin word meaning ridge, wrinkle or fold. For descriptive purposes palatine rugae are anatomical ridges, folds or wrinkles in the anterior part of the palatal mucosa. The rugae are present on either side of the median palatal raphe behind the incisive papilla. Approximately four to seven rugae are seen on either side of the midpalatine raphe (Figure 6).

Based on the shape of the rugae they have been categorized as curved, wavy, straight and circular. Individual studies have shown that males generally have slightly more number of palatine rugae and the left side of the palate shows slightly more number of rugae in both males and females. No bilateral symmetry is seen in the number of rugae. As age advances, the length of the rugae and the transverse palatal rugal region width increases.

Luke (1988) studied the development of palatal rugae in mice. He showed that the rugae develop as localized regions of epithelial proliferation and thickening prior to the elevation of the palatal shelves. Later on, the fibroblasts and collagen fibers accumulate within the connective tissue beneath the thickened epithelium and then assume a characteristic orientation. The direction of the collagen fibers running across the base of the palatine rugae determines their orientation.

In the human embryos the palatal rugae are usually prominent and present throughout the length of the palatal shelves at the time of their elevation. At about the 550 mm stage of the embryo there are about five to seven symmetrical ridges. The anterior ridges originate at the midpalatine raphe. Other ridges are seen laterally.

However, toward the end of the intrauterine life, the posterior ridges almost disappear completely and the anterior ridges become compressed and prominent.

It is believed that the role of rugae in humans is more or less vestigial. However, in animals palatine rugae help in suckling and feeding.

Classification of Palatine Rugae Based on Length

Kapali et al (1997) in their study to evaluate the palatal rugae patterns in Australian Aborigines and Caucasians used the following clinical classification:

On histological examination palatine rugae are stratified squamous (predominantly parakeratinized) epithelium on a connective tissue base, which is similar to the adjacent palatal tissue.

Palatal rugae pattern analysis has been employed successfully in positive human identification. Coslet et al (1980) reported that the palatal rugae returned back in several months after its surgical removal.

Many studies have shown that although minor changes in the morphology of the rugae occur due to orthodontic tooth movement, extractions, aging and palatal expansion, these do not significantly alter the rugal morphology enough to hamper identification.

Lingual Varices

Lingual varices are characterized by the presence of tortuous dilated veins on the ventral surface of the tongue. It is estimated that approximately 10% of the patients in the 4th decade and above exhibit lingual varicosities and the extent of the varicosities increases with advancing age. Lingual varices have been referred to by various other names in literature such as phlebectasia linguae, caviar lesions and linguae varicosities.

Etiopathogenesis

Various theories have been proposed to explain the occurrence of these varices. Ettinger et al (1974) showed that the incidence of varicosities increases with age. Koscard et al (1970) reported that the elastic support to capillaries significantly diminishes with advancing age. This reduction in the elastic support of the connective tissue supporting the blood vessels leads to dilation of capillaries and formation of varicosities. It is also suggested that these are due to abnormally dilated and tortuous veins (varices), as they are not protected by surrounding tissues against hydrostatic pressure.

Eddy et al (1977) studied the role of vitamin C in 22 elderly vegetarians. He showed that vegetarians had high levels of ascorbic acid values in plasma (10.2 ± 0.4 mg/l), compared to other elderly individuals. He concluded that there was a lower incidence of sublingual petechiae and varicosities in the vegetarian group.

Clinical features

In this condition multiple, bluish-purple papular blebs are seen on the ventral and lateral borders of the tongue and occasionally seen on the lips and buccal mucosa. Ventral surface of tongue reveals the presence of tortuous and dilated veins (Figure 7). Susmita et al (2006) reported a case with palatal varicosities. These are usually seen in the elderly and are not symptomatic unless the varices are thrombosed. Jassar et al (2000) reported a symptomatic case of sublingual varices in a patient with portal hypertension secondary to liver cirrhosis.

Circumvallate Papillae or Vallate Papillae

The word vallate is derived from the Latin word vallatus, which means walled. Hence circumvallate papillae do not project out onto the surface of the tongue. They are surrounded by a marginal groove. Each of the papillae are attached to the tongue via their slender bases.

Roughly eight to 12 large (3–5 mm in diameter) mushroom shaped papillae are arranged all along the V-shaped sulcus terminalis that divides the tongue into the body and base (Figure 8). However, occasionally they tend to grow in size when inflamed.

Histologically, the surface of the vallate papillae exhibits secondary papillae that are covered by stratified squamous epithelium. The epithelium lining the lateral surface of the papillae shows numerous taste buds (Figure 9). The minute ducts of the von Ebner’s glands pours its serous secretions into the base of the circular depression (trough). It is believed that the secretions of the von Ebner’s glands is the primary source of salivary lipase and it also cleanses the trough so that the taste buds can respond to various stimuli instantaneously.

Sbarbati et al (1999) suggest that the concept of von Ebner’s gland described as ancillary to the taste buds (washing the trough around the vallate papillae or in perireceptorial events) should be discarded. In their laboratory studies they have found that the von Ebner’s gland and the vallate papillae form a single functional unit. They suggest this unit be termed ‘circumvallate papilla/von Ebner’s gland (CP/VEG) complex’. They believe that the CP/VEG complex represented an important enzyme– and pheromoneproducing system composed of a sensitive (taste buds) and an effectory (VEG) branch linked by feedback mechanisms of control. They hypothesize that the taste buds located in the distal portion of the VEG ductal system can be considered similar to the chemoreceptor cells located in other parts of the digestive apparatus such as pancreatic and bile ducts. Hence, they concluded that the CP/VEG complex represented a rare example of chemoreceptor-secretory organ.

Though, circumvallate papillae are usually not readily evident on the surface of the tongue, some patients tend to panic when they notice these mushroom-shaped papillae while brushing their teeth. Patients need to be educated about their normal presence.

Parotid Papilla

Stensen’s duct of the parotid salivary gland opens into the oral cavity in the buccal mucosa opposite to the maxillary first and second molars.

In many instances the orifice is hardly noticeable. However in some individuals a small, triangular raised pink to red color papule or nodule is readily visible. This flap of tissue covering the orifice of the Stensen’s duct is called parotid papilla (Figure 10). Parotid papillae are usually seen bilaterally. As a result of their anatomic location adjacent to the occlusal plane, the parotid papillae are common sites for formation of traumatic ulcers.

Racial Pigmentation/Physiological Pigmentation

Pigmentation of the oral mucosa can occur due to a wide variety of endogenous and exogenous agents. Most of these are due to five basic pigments, namely, melanin, melanoid, oxyhemoglobin, reduced hemoglobin and carotene.

Physiologic oral pigmentations are genetically determined. Various stimuli, such as trauma, hormonal changes, medication and radiation may result in an increased production of melanin. An age-related increase of oral melanocytes has also been observed.

In dark-skinned people, oral pigmentation increases, but there is no difference in the number of melanocytes between fair-skinned and dark-skinned individuals. The variation is related to the differences in the activity of melanocytes.

Clinical features

Physiologic pigmentation, which is common in African, Asian and Mediterranean populations is probably to the greater melanocyte activity. Oral physiological pigmentation is present in all races and seen equally in males and females. The pigmentation develops during the first decade of life but the patient may not be aware of it. The color depends on the amount of melanin produced and the site where it is deposited, which may vary from brown to black.

It is clinically manifested as multifocal or diffuse melanin pigmentation. The attached gingiva is the most common intraoral site of such pigmentation (Figure 11), where it appears as a bilateral, well-demarcated, ribbon-like, dark brown band that usually spares the marginal gingiva. Other sites of involvement are the tongue (Figure 12), lips, buccal and labial mucosa and perioral skin.

Pathophyisology

The pigmentation of the skin depends on the natural pigment produced in the body called melanin. Melanin is formed by melanocytes, which are located at the stratum basale of the epidermis. Head and neck region is the first site of the body where melanocytes appear after approximately 10 weeks of gestation. These melanocytes produce melanin from tyrosine by the action of tyrosinase. The melanin that is formed is transported in the form of melanosomes to keratinocytes via the dendritic processes of the melanocytes.

Melanosomes persist in dark complexioned individuals. However in fair skinned individuals the cells in the skin breakdown the melanosomes and the melanin. Albinic individuals exhibit very minimal or no presence of melanin. Though all human beings have almost similar concentration of melanocytes, based on the race of the individual, melanin producing genes stimulate the production of melanin. Melanin is normally found in the skin, produced by melanocytes, its functions include absorption of ultraviolet light and scavenging of some cytotoxic compounds.

There are typically three forms of melanin; namely, pheomelanin, eumelanin and neuromelanin. Eumelanin is found in abundant quantities. It is present in the skin and hair. It can produce colors ranging from black to gray and brown to yellow. Pheomelanin is abundantly found in women. It can produce colors ranging from pink to red. Neuromelanin is responsible for the pigmentation of four nuclei of the brain, namely, substantia nigra, locus ceruleus, median raphe nucleus of pons and dorsal motor nucleus of the vagus nerve.

Hairy Tongue

This condition has also been referred to as black hairy tongue. Etiology is unknown, however certain predisposing factors include poor oral hygiene, frequent use of mouthwashes, smoking and alcohol consumption, radiation therapy for head and neck cancers, fungal infections, topical or systemic antibiotics and corticosteroids and debilitating systemic illness.

Clinical features

The condition is characterized by the hypertrophy of the filiform papillae on the dorsum, producing a hairy appearance. This condition results from inadequate desquamation or increased keratinization of the papillae. The filiform papillae are usually about 1 mm in length. However in hairy tongue these papillae may elongate to about 10 mm.

Though the condition has historically been referred to as black hairy tongue, the color can vary from yellow to brown to black (Figure 13). The coloration depends on the chromogenic bacteria, consumption of beverages like tea and coffee and tobacco use. This condition is usually asymptomatic. However some individuals complain of altered taste sensation, halitosis and occasionally gagging sensation.

Histologically hyperkeratosis of the filiform papillae is seen.

Patients should be advised to avoid excessive consumption of beverages like tea and coffee. They should also be advised to discontinue the use of tobacco. They can be motivated to use a medium bristled brush over the dorsal surface of the tongue.

Mlandibular and Maxillary Tori

Exostoses

Exostoses or hyperostoses are non-pathologic, benign bony growths projecting outward from the cortical plate. Though exostoses are developmental disturbances they are usually noticed only in adulthood and may enlarge with age. They are asymptomatic and self-limiting. It is estimated that the prevalence rate of tori is approximately 27 in every 1,000 individuals. Eskimos, American Indians and Asians and more specifically Koreans are said to have a higher incidence of tori.

Torus/Tori

The word torus is derived from Latin, which means a swelling or bulge. Although etiology is unknown, a hereditary basis is suspected. A torus located along the midline of the hard palate is called a palatal torus, or torus palatinus, and a torus in the lingual aspect of the mandible is called a mandibular torus, or torus mandibularis.

Torus palatinus

This condition exhibits exostoses in the midline of the hard palate. It may be inherited as an autosomal dominant trait. In individual studies the incidence of palatal tori among the population of United States has been reported as high as 20–35%. It is believed to be twice as prevalent in females as in males.

The tori in the palatal vault may vary in size from a few centimeters to larger sized lesions and are usually lobu-lated and dome shaped with a smooth surface (Figure 14). These exostoses generally tend to enlarge with age. Histopathologically smaller lesions are composed of compact bone. However larger tori may exhibit a central core of cancellous bone covered by compact bone.

Buccal exostoses

Buccal exostoses are benign, broad-based surface masses of the outer or facial aspect of the maxilla (Figure 16) and less commonly, the mandible (5.1:1). They begin to develop in early adulthood and may very slowly enlarge over the years.

Reactive Subpontine Exostoses

It has also been referred to as subpontic osseous hyperplasia. It is a reactive exostoses arising from the crest of the alveolar ridge beneath the pontic of a fixed partial denture presenting as nodule or protruberance of crestal bone. It was first reported in 1971 by Calman et al.

It may have a genetic origin similar to other exostoses. However some authors believe that a chronic gingival irritation leads to the subpontic bone proliferation.

Soft Tissue Disturbances

Developmental Disorders Affecting Tongue

Aglossia/Lingual Agenesis/Aglossia Congenita

Failure in the embryogenesis of lateral lingual swellings during intrauterine life leads to this rare and highly fatal condition of absence of tongue. However literature review reveals reports of individuals living a relatively normal life. Khalil et al (1995) reported aglossia in a 30-year-old man. It may occur alone or in association with other deformities including micrognathia; microsomia; congenital absence of mandibular incisors; collapse of the mandibular arch; sagittal band between the floor of the mouth and the palate; and situs inversus (also called situs transversus–congenital condition where all major visceral organs such as the heart, stomach, spleen, liver, etc. are placed reversed or mirrored from their normal position). Functional thyroid disorder may develop because of the embryological association between development of tongue and thyroid gland. The absence of the lingual muscular stimulus generally affects the development of jaws and results in malocclusion of teeth. These individuals have impaired speech and difficulty in swallowing. Highasi et al (1996) reported conductive deafness, esophageal atre-sia, hypoplastic epiglottis and ptosis of the eyelid in an individual with aglossia.

Macroglossia

An abnormally enlarged tongue is one that protrudes beyond the teeth or the alveolar ridge in the resting position (Figure 19). Macroglossia can be broadly categorized as true macroglossia and pseudo macroglossia (Table 1). In true macroglossia enlarged tongue is associated with histological abnormalities. In pseudo macroglossia (relative macroglossia) the enlargement is apparent; though histology does not provide a pathologic explanation (e.g. Down’s syndrome).

Table 1

Classification of macroglossia

image

image

Modified from Richard D Thrasher III (2007)

Ankyloglossia/Tongue-tie

Ankyloglossia or tongue-tie, is the result of a short, tight, thick, lingual frenulum causing tethering of the tongue tip (Figure 20). Messner (2000) reported that the incidence of ankyloglossia ranged from 0.02% to 4.8% in newborns.

Geographic Tongue

Geographic tongue has also been referred to as benign migratory glossitis, wandering rash of the tongue, annulus migrans, stomatitis areata migrans and erythema areata migrans. It is a common benign condition that is seen in almost 3% of the population. Geographic tongue is seen in males and females equally. However, few articles in literature describe a slightly higher female predilection (2:1). However, the tongue changes are more prominent in adults compared to children.

Etiopathogenesis and predisposing factors

The etiopathogenesis of the condition is still not understood. Histologically it is said to be an inflammatory condition associated with human leukocyte antigen (HLA)-DR5, HLA-DRW6, and HLA-Cw6. Eidelman et al (1976) reported that many of the parents and siblings of individuals with geographic tongue also presented with the condition. This substantiated the possibility of heredity being an etiological factor.

Guimaraes et al (2007) in their investigations found that the polymorphism + 954 interleukin (IL)-1B is associated with an increased risk of developing geographic tongue.

Redman et al (1966) and Bánóczy (1975) et al suggested that emotional stress was associated with the occurrence and severity of geographic tongue.

There are many studies with regard to the association of geographic tongue and diabetes mellitus. Wysocky et al (1987) reported a four-fold increase in the presence of geographic tongue in diabetics. However, Guggenheimer et al (2000) reported no significant correlation between geographic tongue and insulin-dependent diabetes mellitus.

Waltimo (1991) in his study on the severity of geographic tongue in a patient taking oral contraceptive pills reported that the tongue changes were the severest on the 17th day of the menstrual cycle.

Marks and Simon (1979) showed a definitive association between geographic tongue and atopy.

Many authors postulate that psoriasis manifests orally as geographic tongue. Gonzaga (1996) in his investigations showed a significant association of Cw6 with both psoriasis and benign migratory glossitis. This antigen was found in 59.1% of the patients with psoriasis and 43.8% of the patients with benign migratory glossitis. Zargari (2006) in a study including 306 patients with psoriasis concluded that geographic tongue is more common in early onset psoriasis and may be an indicator of the severity of psoriasis.

Yarom et al (2004) found a strong correlation between the occurrence of geographic tongue and fissured tongue.

Clinical features

Geographic tongue is commonly seen in the 2nd decade of life.

The common sites of involvement are the tip of the tongue, lateral margins and dorsum of the tongue. However some lesions tend to extend to the ventral surface.

The appearance of the lesion typically mimics geographic outlines on a map, hence the name geographic tongue (Figure 21). It appears as circinate irregular erythematous patches which represent the atrophic filiform papillae, bound by keratotic white bands or lines which represent the regenerating filiform papillae (Figure 22).

These erythematous patches occur in multiple sites on the tongue. Very rarely a single site of involvement may be seen. In this condition the filiform papillae regenerate in the atrophic site in a few days and a new site begins to reveal atrophy. Patients typically report this as ‘migrating rash’.

Many patients are unaware of the condition as it is generally asymptomatic. However, some report of inability to consume spicy food owing to burning sensation. Some authors believe that the association of fissured tongue with superimposed candidal infection causes the burning sensation. The condition is seldom painful.

Though this condition is typically seen involving the tongue, it can occur on other sites in the oral mucosa. Some authors use terms such as ectopic geographic tongue, geographic stomatitis, erythema migrans, erythema areata migrans, and stomatitis areata to refer to such a finding. The common ectopic sites include the buccal mucosa, labial mucosa (Figure 23), gingiva, floor of mouth and less commonly the soft palate and uvula.

Lingual Thyroid

Failure of the thyroid tissue to descend from its developmental origin at the foramen caecum to its normal pretracheal location leads to its presence in the tongue at the foramen caecum. Van Der Gaag et al (1985) postulated that maternal antithyroid immunoglobulins may arrest the descent of the thyroid in some individuals.

Thyroid tissue may be deposited ectopically along this early thyroglossal tract. Apart from tongue, ectopic thyroid tissue has also been reported at other midline locations of the neck such as below the level of hyoid bone, larynx and trachea, mediastinum and esophagus.

It is estimated that the incidence of lingual thyroid varies between 1:3,000 and 1:100,000 (Williams et al, 1989).

The lingual thyroid is seen as a nodular mass in the midline about 2–3 cm in diameter with a smooth surface. It appears erythematous when highly vascular. Depending on the size, it may produce symptoms of pain, feeling of fullness in the throat, dysphagia, dysphonia and dyspnea.

The diagnostic test is thyroid scan with iodine isotopes or technetium-99m, CT scan or MRI helps in delineating the size and extent of the lesion. Biopsy is avoided as there is risk of hemorrhage and it could be the only thyroid tissue (in about 70% cases). Histopathologically it resembles normal thyroid tissue. If it has to be excised, it should be done after confirming the presence of a functioning thyroid in the normal position. If it is not so, then the excised tissue is transplanted in a muscle with adequate vascularity.

Developmental Disorders Affecting the Lip

Paramedian Lip Pits (Congenital Lip Pits)

These congenital invaginations of the lower lip arise from persistent lateral sulci on the embryonic mandibular arch. They are seen as bilateral (occasionally unilateral), symmetrical pits on the vermillion border on either side of the midline ranging from subtle depressions to prominent humps. This trait may be transmitted genetically to the offspring.

These can extend to a depth of 1.5 cm. On squeezing they may express salivary secretions. These lip pits may be a part of Van der Woude syndrome or popliteal pterygium syndrome. Histopathologically, tracts lined by stratified squamous epithelium are seen; minor salivary glands may be seen communicating with the sinus. Surrounding connective tissue is often infiltrated by chronic inflammatory cells. Excision of these pits may be performed for cosmetic reasons.

Commissural Lip Pits

These small mucosal invaginations occur at the corners of the mouth on the vermillion border (unilaterally or bilaterally), possibly due to failure of fusion of embryonal maxillary and mandibular processes (Figure 25). Though considered congenital, these often develop later in life – prevalence in children (0.2–0.7%) being much lower than in adults (12–20%). Males are more often affected than females. An autosomal dominant pattern of transmission is noted in some families. In most cases, they are asymptomatic and are discovered on routine examination; they may express saliva on squeezing. The depth of these pits range from 1mm to 4 mm. Associated preauricular pits may be seen in some. They are generally not associated with facial or palatal clefts. Histopathologically they are similar to paramedian lip pits.

No treatment is necessary. However excision is indicated if there is excessive salivary secretion or secondary infection.

Cleft Lip and Cleft Palate

Cleft lip results from failure of merging of epithelial groove between the medial and lateral nasal process by penetration of mesodermal cells. Cleft palate is the result of epithelial breakdown with in growth failure of mesodermal tissue and lack of lateral palatal segment fusion. Most cleft cases are polygenic but the 5% of cleft cases associated with syndromes are said to be monogenic (Tables 2 and 3). Environmental factors like nutritional deficiencies, stress, infections, alcohol, drugs, toxins and ischemia may cause clefts.

Table 2

Syndromes associated with cleft lip

Achondroplasia

Beckwith–Wiedemann syndrome

Fetal alcohol syndrome

Goldenhar syndrome

Gorlin syndrome

Treacher Collins syndrome

Van der Woude syndrome

Waardenburg syndrome

Table 3

Syndromes associated with cleft palate

Achondroplasia

Beckwith–Wiedemann syndrome

Cleidocranial dysplasia

Crouzon syndrome (craniofacial dysostosis)

Ehlers–Danlos syndrome

Fetal alcohol syndrome

Gorlin syndrome (basal cell nevus syndrome)

Marfan syndrome

Pierre Robin syndrome

Rubinstein–Taybi syndrome

Treacher Collins syndrome (mandibulofacial dysostosis)

Van der Woude syndrome

Veau system of classification is generally used where the emphasis is on the extent to which the clefting is/>

Jan 12, 2015 | Posted by in Oral and Maxillofacial Radiology | Comments Off on 2: Developmental Disturbances
Premium Wordpress Themes by UFO Themes