Definitions
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Choristoma : An overgrowth of tissues that is mature and found in an area where such tissue is not usually present, such as an osseous or cartilaginous choristoma of the tongue.
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Hamartoma : An overgrowth of tissue that is mature and normally found in that area, such as a leiomyomatous hamartoma.
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Nevus : An overgrowth of tissue that is normally found in the skin or oral mucosa, such as melanocytic, epidermal, or vascular nevus.
Epithelial Lesions
Developmental macular epithelial conditions fall into three categories: diffuse white lesions, diffuse red lesions, and nevi that may be mucosa-colored or pigmented. Diffuse white lesions are often dyskeratotic and represent oral manifestations of genodermatoses, of which the most well-known is the Cannon white sponge nevus that involves mucosal sites only. Dyskeratosis congenita results in keratotic skin lesions and oral dysplastic leukoplakias. Oral lesions of pachyonychia congenita are rarely biopsied, because the diagnosis is established via skin biopsies. Oral lesions of hereditary mucoepithelial dysplasia, a condition of defective expression of cytoskeleton junctional elements, presents as erythematous plaques.
Macular Epithelial Lesions
White Sponge Nevus (Cannon White Sponge Nevus)
Clinical Findings
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Lesions are noted in the first two decades of life and persist throughout life. The skin is not involved, although there may be esophageal, upper airway, and genital involvement.
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The buccal mucosa (the most commonly affected site) appears white to gray, folded, painless, edematous, and spongy. The tongue, lip mucosa, and floor of the mouth may also be involved ( Fig. 2.1 ).
FIG 2.1 (A) and (B) White sponge nevus: diffuse, boggy white plaques of the buccal mucosa present bilaterally.(Courtesy Dr. Carl Allen, The Ohio State University, Columbus, Ohio.)
Etiopathogenesis and Histopathologic Features
White sponge nevus is a rare, autosomal dominant condition resulting from a mutation of the helical domain on keratins K4 (chromosome 12q) and K13 (chromosome 17q), leading to keratin instability and abnormal tonofilament aggregation. There may be abnormal degradation of K13 protein and abnormal ubiquitination.
- •
Variable parakeratosis and acanthosis with a “spongy appearance” are noted. The last is caused by cytoplasmic vacuolation (partly due to glycogen) and not spongiosis. There is minimal to no inflammation ( Fig. 2.2A–C ).
FIG 2.2 White sponge nevus. (A) The epithelium exhibits acanthosis with a pale “spongy” appearance. (B) The pale epithelium is caused by intracellular vacuolation and dyskeratosis that spares the basal cells. (C) There is positive periodic acid–Schiff staining of intracytoplasmic granules typical for glycogen. (D) Perinuclear eosinophilic condensations and intracytoplasmic vacuolation (not spongiosis). - •
Perinuclear eosinophilic condensations of keratin and dyskeratotic cells are the sine qua non for diagnosis ( Fig. 2.2D ). Rare cases exhibit epidermolytic hyperkeratosis.
Differential Diagnosis
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Chronic frictional keratosis of the buccal mucosa, a very common condition, exhibits parakeratosis, acanthosis, and keratinocytic edema but not perinuclear keratin condensations (see Chapter 10 ).
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Hereditary benign intraepithelial dyskeratosis (see later) exhibits dyskeratosis and “cell-within-a-cell” structures but not perinuclear condensations.
Management and Prognosis
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There is no effective treatment. Patients who purportedly respond to antibiotic or chlorhexidine therapy are likely to have some other entity, such as frictional keratoses, which typically wax and wane.
References
White Sponge Nevus (Cannon White Sponge Nevus)
Clinical Findings
- •
Lesions are noted in the first two decades of life and persist throughout life. The skin is not involved, although there may be esophageal, upper airway, and genital involvement.
- •
The buccal mucosa (the most commonly affected site) appears white to gray, folded, painless, edematous, and spongy. The tongue, lip mucosa, and floor of the mouth may also be involved ( Fig. 2.1 ).
FIG 2.1 (A) and (B) White sponge nevus: diffuse, boggy white plaques of the buccal mucosa present bilaterally.(Courtesy Dr. Carl Allen, The Ohio State University, Columbus, Ohio.)
Etiopathogenesis and Histopathologic Features
White sponge nevus is a rare, autosomal dominant condition resulting from a mutation of the helical domain on keratins K4 (chromosome 12q) and K13 (chromosome 17q), leading to keratin instability and abnormal tonofilament aggregation. There may be abnormal degradation of K13 protein and abnormal ubiquitination.
- •
Variable parakeratosis and acanthosis with a “spongy appearance” are noted. The last is caused by cytoplasmic vacuolation (partly due to glycogen) and not spongiosis. There is minimal to no inflammation ( Fig. 2.2A–C ).
FIG 2.2 White sponge nevus. (A) The epithelium exhibits acanthosis with a pale “spongy” appearance. (B) The pale epithelium is caused by intracellular vacuolation and dyskeratosis that spares the basal cells. (C) There is positive periodic acid–Schiff staining of intracytoplasmic granules typical for glycogen. (D) Perinuclear eosinophilic condensations and intracytoplasmic vacuolation (not spongiosis). - •
Perinuclear eosinophilic condensations of keratin and dyskeratotic cells are the sine qua non for diagnosis ( Fig. 2.2D ). Rare cases exhibit epidermolytic hyperkeratosis.
Differential Diagnosis
- •
Chronic frictional keratosis of the buccal mucosa, a very common condition, exhibits parakeratosis, acanthosis, and keratinocytic edema but not perinuclear keratin condensations (see Chapter 10 ).
- •
Hereditary benign intraepithelial dyskeratosis (see later) exhibits dyskeratosis and “cell-within-a-cell” structures but not perinuclear condensations.
Management and Prognosis
- •
There is no effective treatment. Patients who purportedly respond to antibiotic or chlorhexidine therapy are likely to have some other entity, such as frictional keratoses, which typically wax and wane.
Clinical Findings
- •
Lesions are noted in the first two decades of life and persist throughout life. The skin is not involved, although there may be esophageal, upper airway, and genital involvement.
- •
The buccal mucosa (the most commonly affected site) appears white to gray, folded, painless, edematous, and spongy. The tongue, lip mucosa, and floor of the mouth may also be involved ( Fig. 2.1 ).
FIG 2.1 (A) and (B) White sponge nevus: diffuse, boggy white plaques of the buccal mucosa present bilaterally.(Courtesy Dr. Carl Allen, The Ohio State University, Columbus, Ohio.)
Etiopathogenesis and Histopathologic Features
White sponge nevus is a rare, autosomal dominant condition resulting from a mutation of the helical domain on keratins K4 (chromosome 12q) and K13 (chromosome 17q), leading to keratin instability and abnormal tonofilament aggregation. There may be abnormal degradation of K13 protein and abnormal ubiquitination.
- •
Variable parakeratosis and acanthosis with a “spongy appearance” are noted. The last is caused by cytoplasmic vacuolation (partly due to glycogen) and not spongiosis. There is minimal to no inflammation ( Fig. 2.2A–C ).
FIG 2.2 White sponge nevus. (A) The epithelium exhibits acanthosis with a pale “spongy” appearance. (B) The pale epithelium is caused by intracellular vacuolation and dyskeratosis that spares the basal cells. (C) There is positive periodic acid–Schiff staining of intracytoplasmic granules typical for glycogen. (D) Perinuclear eosinophilic condensations and intracytoplasmic vacuolation (not spongiosis). - •
Perinuclear eosinophilic condensations of keratin and dyskeratotic cells are the sine qua non for diagnosis ( Fig. 2.2D ). Rare cases exhibit epidermolytic hyperkeratosis.
Differential Diagnosis
- •
Chronic frictional keratosis of the buccal mucosa, a very common condition, exhibits parakeratosis, acanthosis, and keratinocytic edema but not perinuclear keratin condensations (see Chapter 10 ).
- •
Hereditary benign intraepithelial dyskeratosis (see later) exhibits dyskeratosis and “cell-within-a-cell” structures but not perinuclear condensations.
References
Hereditary Benign Intraepithelial Dyskeratosis
Clinical Findings
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This is diagnosed in the first two decades of life and affects Haliwa-Saponi Native Americans in North Carolina and their descendants (usually on the east coast of the United States), although sporadic cases exist. The skin is not affected.
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The oral mucosa exhibits diffuse, thickened, painless, spongy white plaques similar to white sponge nevus.
- •
Eye lesions are present as gelatinous plaques on bulbar conjunctiva in a perilimbic location.
Etiopathogenesis and Histopathologic Features
Hereditary benign intraepithelial dyskeratosis is an autosomal dominant condition resulting from a duplication on chromosome 4q35.
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Parakeratosis, acanthosis, and many dyskeratotic “tobacco” cells (so called because of their brown color seen in Papanicolaou stains) are located in the upper epithelium. Sometimes these dyskeratotic cells are surrounded by epithelial cells, resulting in a cell-within-a-cell appearance ( Fig. 2.3 ).
FIG 2.3 Hereditary benign intraepithelial dyskeratosis. (A) Parakeratosis and acanthosis with dyskeratosis. (B) Prominent dyskeratosis within the superficial keratinocytes. (C) Dyskeratotic cells with “cell-within-a-cell” morphology.
Differential Diagnosis
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White sponge nevus shows perinuclear keratin condensations.
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Darier disease or warty dyskeratoma is acantholytic with dyskeratosis but without the cell-within-a-cell appearance.
Management and Prognosis
- •
There is no effective treatment.
References
Clinical Findings
- •
This is diagnosed in the first two decades of life and affects Haliwa-Saponi Native Americans in North Carolina and their descendants (usually on the east coast of the United States), although sporadic cases exist. The skin is not affected.
- •
The oral mucosa exhibits diffuse, thickened, painless, spongy white plaques similar to white sponge nevus.
- •
Eye lesions are present as gelatinous plaques on bulbar conjunctiva in a perilimbic location.
Etiopathogenesis and Histopathologic Features
Hereditary benign intraepithelial dyskeratosis is an autosomal dominant condition resulting from a duplication on chromosome 4q35.
- •
Parakeratosis, acanthosis, and many dyskeratotic “tobacco” cells (so called because of their brown color seen in Papanicolaou stains) are located in the upper epithelium. Sometimes these dyskeratotic cells are surrounded by epithelial cells, resulting in a cell-within-a-cell appearance ( Fig. 2.3 ).
FIG 2.3 Hereditary benign intraepithelial dyskeratosis. (A) Parakeratosis and acanthosis with dyskeratosis. (B) Prominent dyskeratosis within the superficial keratinocytes. (C) Dyskeratotic cells with “cell-within-a-cell” morphology.
References
Keratosis Follicularis (Darier Disease, Darier-White Disease)
Darier disease in the mouth does not occur in the absence of skin lesions. A localized papule or nodule with similar histopathology is known as warty dyskeratoma or focal acantholytic dyskeratosis and is discussed in Chapter 10 .
Clinical Findings
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Onset occurs in first and second decades of life with lesions on the palatal mucosa, gingiva, or tongue, all keratinized sites. White, painless, keratotic papules (seen in mild disease) or plaques, and cobblestoning of the oral mucosa (seen in more severe disease) are noted in 10% to 50% of patients with skin disease ( Fig. 2.4 ). Up to one-third of cases exhibit parotid or submandibular swelling that is likely due to strictures and obstruction.
FIG 2.4 Darier disease: diffuse, pebbly white papules on the hard palate.(From Frezzini C, Cedro M, Leao JC, Porter S. Darier disease affecting the gingival and oral mucosal surfaces. Oral Surg Oral Med Oral Pathol Oral Radiol Endod . 2006;102:e29–e33.)
Etiopathogenesis and Histopathologic Features
Darier disease is an autosomal dominant disorder associated with a mutation of the ATP2A2 gene, which encodes sarcoendoplasmic Ca 2+ -ATPase isoform 2. This protein is involved in the transport of calcium from the cytoplasm into the endoplasmic reticulum as well as posttranslational protein processing required for proper functioning of desmosomes and keratin. The mutation results in dyscohesion.
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Skin biopsies show marked parakeratosis, acanthosis, dyskeratosis presenting as rounded eosinophilic bodies (corps ronds) as well as spindled eosinophilic structures (grains).
Management and Prognosis
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Darier disease is managed with topical steroids, retinoids, calcineurin inhibitors, diclofenac sodium, laser therapy, and photodynamic therapy.
References
Clinical Findings
- •
Onset occurs in first and second decades of life with lesions on the palatal mucosa, gingiva, or tongue, all keratinized sites. White, painless, keratotic papules (seen in mild disease) or plaques, and cobblestoning of the oral mucosa (seen in more severe disease) are noted in 10% to 50% of patients with skin disease ( Fig. 2.4 ). Up to one-third of cases exhibit parotid or submandibular swelling that is likely due to strictures and obstruction.
FIG 2.4 Darier disease: diffuse, pebbly white papules on the hard palate.(From Frezzini C, Cedro M, Leao JC, Porter S. Darier disease affecting the gingival and oral mucosal surfaces. Oral Surg Oral Med Oral Pathol Oral Radiol Endod . 2006;102:e29–e33.)
Etiopathogenesis and Histopathologic Features
Darier disease is an autosomal dominant disorder associated with a mutation of the ATP2A2 gene, which encodes sarcoendoplasmic Ca 2+ -ATPase isoform 2. This protein is involved in the transport of calcium from the cytoplasm into the endoplasmic reticulum as well as posttranslational protein processing required for proper functioning of desmosomes and keratin. The mutation results in dyscohesion.
- •
Skin biopsies show marked parakeratosis, acanthosis, dyskeratosis presenting as rounded eosinophilic bodies (corps ronds) as well as spindled eosinophilic structures (grains).
References
Hereditary Mucoepithelial Dysplasia
Clinical Findings
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Usually diagnosed in childhood, this disorder is characterized by perineal and oral erythema, nonscarring alopecia, and eye abnormalities. Patients may also have keratosis follicularis, airway disease, and recurrent infections.
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Bright red demarcated plaques of the gingiva and hard palatal mucosa, angular cheilitis, and fissured tongue are seen. The dentition is normal ( Fig. 2.5A ).
FIG 2.5 Hereditary mucoepithelial dysplasia. (A) Demarcated erythema of the gingiva. (B) Gingival tissue biopsy sample showing scattered dyskeratotic keratinocytes and spongiosis.(From Hernández-Martín A, Colmenero I, Torrelo A. Hereditary mucoepithelial dysplasia: report of two sporadic cases. Pediatr Dermatol . 2012;29:311–315.)
Etiopathogenesis and Histopathologic Features
Hereditary mucoepithelial dysplasia is an autosomal condition (although there are also sporadic cases) resulting from abnormalities in gap junctions and desmosome formation, leading to epithelial dyscohesion. The responsible gene has yet to be identified.
- •
There is variable papillomatosis, dyscohesion, dyskeratosis, vacuolations within keratinocytes, and lack of intercellular bridges. Dyskeratotic cells are sometimes seen within keratinocytes, giving a cell-within-a-cell appearance ( Fig. 2.5B ).
- •
Ultrastuctural examination reveals a reduced number of desmosomes and internalized gap junctions.
Management and Prognosis
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There is no effective treatment.
References
Clinical Findings
- •
Usually diagnosed in childhood, this disorder is characterized by perineal and oral erythema, nonscarring alopecia, and eye abnormalities. Patients may also have keratosis follicularis, airway disease, and recurrent infections.
- •
Bright red demarcated plaques of the gingiva and hard palatal mucosa, angular cheilitis, and fissured tongue are seen. The dentition is normal ( Fig. 2.5A ).
FIG 2.5 Hereditary mucoepithelial dysplasia. (A) Demarcated erythema of the gingiva. (B) Gingival tissue biopsy sample showing scattered dyskeratotic keratinocytes and spongiosis.(From Hernández-Martín A, Colmenero I, Torrelo A. Hereditary mucoepithelial dysplasia: report of two sporadic cases. Pediatr Dermatol . 2012;29:311–315.)
Etiopathogenesis and Histopathologic Features
Hereditary mucoepithelial dysplasia is an autosomal condition (although there are also sporadic cases) resulting from abnormalities in gap junctions and desmosome formation, leading to epithelial dyscohesion. The responsible gene has yet to be identified.
- •
There is variable papillomatosis, dyscohesion, dyskeratosis, vacuolations within keratinocytes, and lack of intercellular bridges. Dyskeratotic cells are sometimes seen within keratinocytes, giving a cell-within-a-cell appearance ( Fig. 2.5B ).
- •
Ultrastuctural examination reveals a reduced number of desmosomes and internalized gap junctions.
References
Oral Linear Epidermal Nevus (Oral Linear Verrucous Nevus, Nevus Unius Lateris)
Clinical Findings
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Generally noted in infancy or childhood, linear pigmented and verrucous papules and plaques occur unilaterally on the skin.
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The corresponding oral papillary plaques may be extensive and multifocal. These are mucosa colored in a unilateral distribution or sometimes at the midline. The lips, tongue, and palatal mucosa are the most common sites. Infrequently, there may be missing teeth or enamel hypoplasia. Oral lesions rarely occur without skin lesions ( Fig. 2.6 ).
FIG 2.6 Oral linear epidermal nevus. (A) Palatal mucosa with linear verrucous mucosal plaque ipsilateral to cutaneous lesion. (B) Oral mucosa exhibiting hyperkeratosis, papillary acanthosis, and sebaceous glands.(From Ozçelik D, Parlak AH, Oztürk A, et al. Unilateral linear verrucous epidermal nevus of the face and the oral mucosa. Plast Reconstr Surg. 2005;115:17e–19e.)
Etiopathogenesis and Histopathologic Features
Linear epidermal nevi are hamartomatous malformations of the epidermis that tend to follow skin tension lines (of Blaschko), possibly resulting from abnormal migration patterns of embryonic cells. Oral involvement is uncommon.
- •
Hyperkeratosis and papillary acanthosis are present, sometimes with sebaceous glands.
Differential Diagnosis
- •
Squamous papillomas and condylomas are solitary lesions and unassociated with linear skin lesions.
- •
Verruca vulgaris exhibits large keratohyalin granules and is also a solitary lesion.
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Sporadic epidermal nevus (extremely rare) in the mouth exhibits a demarcated area of epithelial proliferation with pilosebaceous units and sometimes other adnexal structures.
Management and Prognosis
- •
Excision or laser ablation is performed for oral lesions. Skin cases may recur.
References
Clinical Findings
- •
Generally noted in infancy or childhood, linear pigmented and verrucous papules and plaques occur unilaterally on the skin.
- •
The corresponding oral papillary plaques may be extensive and multifocal. These are mucosa colored in a unilateral distribution or sometimes at the midline. The lips, tongue, and palatal mucosa are the most common sites. Infrequently, there may be missing teeth or enamel hypoplasia. Oral lesions rarely occur without skin lesions ( Fig. 2.6 ).
FIG 2.6 Oral linear epidermal nevus. (A) Palatal mucosa with linear verrucous mucosal plaque ipsilateral to cutaneous lesion. (B) Oral mucosa exhibiting hyperkeratosis, papillary acanthosis, and sebaceous glands.(From Ozçelik D, Parlak AH, Oztürk A, et al. Unilateral linear verrucous epidermal nevus of the face and the oral mucosa. Plast Reconstr Surg. 2005;115:17e–19e.)
Etiopathogenesis and Histopathologic Features
Linear epidermal nevi are hamartomatous malformations of the epidermis that tend to follow skin tension lines (of Blaschko), possibly resulting from abnormal migration patterns of embryonic cells. Oral involvement is uncommon.
- •
Hyperkeratosis and papillary acanthosis are present, sometimes with sebaceous glands.
Differential Diagnosis
- •
Squamous papillomas and condylomas are solitary lesions and unassociated with linear skin lesions.
- •
Verruca vulgaris exhibits large keratohyalin granules and is also a solitary lesion.
- •
Sporadic epidermal nevus (extremely rare) in the mouth exhibits a demarcated area of epithelial proliferation with pilosebaceous units and sometimes other adnexal structures.
References
Epidermal Nevus (Epidermal Choristoma)
Clinical Findings
- •
This usually occurs within the first 3 months of life, presenting as brown plaques or macules, usually on the tongue, although some cases occur in adults. It differs from linear epidermal nevus in that it is unassociated with an overlying epidermal nevus.
Etiopathogenesis and Histopathologic Features
Oral epidermal nevus represents a developmental overgrowth of tissues, such as mature pilosebaceous units and other skin adnexa, that one would not normally see in the oral cavity. If only sebaceous units are present, the term epidermal nevus is more appropriate because sebaceous glands are frequently seen as Fordyce granules in the oral cavity.
- •
Hyperkeratosis, hypergranulosis, melanosis of basal cells without melanocytic hyperplasia, and pilosebaceous and other adnexal structures are noted within the lamina propria.
Differential Diagnosis
- •
Sebaceous hyperplasia (hyperplastic Fordyce granules) is often seen in adults.
Management and Prognosis
- •
Excision is curative.
References
Etiopathogenesis and Histopathologic Features
Oral epidermal nevus represents a developmental overgrowth of tissues, such as mature pilosebaceous units and other skin adnexa, that one would not normally see in the oral cavity. If only sebaceous units are present, the term epidermal nevus is more appropriate because sebaceous glands are frequently seen as Fordyce granules in the oral cavity.
- •
Hyperkeratosis, hypergranulosis, melanosis of basal cells without melanocytic hyperplasia, and pilosebaceous and other adnexal structures are noted within the lamina propria.
References
Nodular or Tumor-Like Lesions
Fordyce Granules, Sebaceous Hyperplasia, Adenoma, and Choristoma
Clinical Findings
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Fordyce granules: these are usually noted in adults, present in up to 60% of the population, and appear as 1- to 3-mm yellowish papules, frequently located on the posterior buccal mucosa and vermilion of the lips, but they may be seen at any site. They are usually bilateral and symmetric ( Fig. 2.7 ).
FIG 2.7 Fordyce granules. (A) Yellow papules on the left buccal mucosa. (B) Yellow papules on the upper vermilion. - •
Sebaceous hyperplasia and adenoma: these are larger, yellowish papules and nodules seen at the same sites as Fordyce granules.
- •
Sebaceous choristoma: these are papules or nodules usually located in the midline of the tongue in the area of the foramen cecum.
Etiopathogenesis and Histopathologic Features
Fordyce granules are considered normal structures in the mouth. They can become hyperplastic and adenomatous. Patients with Muir-Torre syndrome who present with skin sebaceous tumors and internal malignancy have a high prevalence of sebaceous hyperplasia.
- •
Fordyce granules: these consist of mature sebaceous glands with a single germinative layer and may or may not open onto the mucosa via a duct lined by squamous epithelium. Sebocytes have central nuclei and vacuolated cytoplasm. Hair and Demodex folliculorum have been reported ( Fig. 2.8 ).
FIG 2.8 Fordyce granules: two sebaceous glands in the lamina propria. - •
Sebaceous hyperplasia: this consists of at least 15 sebaceous lobules (this number is somewhat arbitrary) opening into a central duct lined by squamous epithelium ( Fig. 2.9 ). The duct may become cystically dilated ( Fig. 2.10 ).
FIG 2.9 Sebaceous hyperplasia. (A) Many lobules of sebaceous glands in the lamina propria without hyperplasia of the germinative layer. (B) Mature sebocytes, secretions within the duct and no proliferation of germinative cells.
FIG 2.10 Sebaceous hyperplasia. (A) Lobular proliferation of sebaceous glands with ducts opening into the oral cavity. (B) Cystically dilated ducts and mature sebocytes. - •
Sebaceous adenoma: this consists of many sebaceous lobules with proliferation of germinative basaloid cells at the periphery of the lobules.
Differential Diagnosis
- •
Some salivary gland neoplasms show foci of sebaceous differentiation, with the majority of the tumor representing a recognizable salivary gland neoplasm.
Management and Prognosis
- •
Excision of sebaceous hyperplasia and adenoma is curative. Very rarely, sebaceous carcinomas arise in the oral cavity.
References
Fordyce Granules, Sebaceous Hyperplasia, Adenoma, and Choristoma
Clinical Findings
- •
Fordyce granules: these are usually noted in adults, present in up to 60% of the population, and appear as 1- to 3-mm yellowish papules, frequently located on the posterior buccal mucosa and vermilion of the lips, but they may be seen at any site. They are usually bilateral and symmetric ( Fig. 2.7 ).
FIG 2.7 Fordyce granules. (A) Yellow papules on the left buccal mucosa. (B) Yellow papules on the upper vermilion. - •
Sebaceous hyperplasia and adenoma: these are larger, yellowish papules and nodules seen at the same sites as Fordyce granules.
- •
Sebaceous choristoma: these are papules or nodules usually located in the midline of the tongue in the area of the foramen cecum.
Etiopathogenesis and Histopathologic Features
Fordyce granules are considered normal structures in the mouth. They can become hyperplastic and adenomatous. Patients with Muir-Torre syndrome who present with skin sebaceous tumors and internal malignancy have a high prevalence of sebaceous hyperplasia.
- •
Fordyce granules: these consist of mature sebaceous glands with a single germinative layer and may or may not open onto the mucosa via a duct lined by squamous epithelium. Sebocytes have central nuclei and vacuolated cytoplasm. Hair and Demodex folliculorum have been reported ( Fig. 2.8 ).
FIG 2.8 Fordyce granules: two sebaceous glands in the lamina propria. - •
Sebaceous hyperplasia: this consists of at least 15 sebaceous lobules (this number is somewhat arbitrary) opening into a central duct lined by squamous epithelium ( Fig. 2.9 ). The duct may become cystically dilated ( Fig. 2.10 ).
FIG 2.9 Sebaceous hyperplasia. (A) Many lobules of sebaceous glands in the lamina propria without hyperplasia of the germinative layer. (B) Mature sebocytes, secretions within the duct and no proliferation of germinative cells.
FIG 2.10 Sebaceous hyperplasia. (A) Lobular proliferation of sebaceous glands with ducts opening into the oral cavity. (B) Cystically dilated ducts and mature sebocytes. - •
Sebaceous adenoma: this consists of many sebaceous lobules with proliferation of germinative basaloid cells at the periphery of the lobules.
Differential Diagnosis
- •
Some salivary gland neoplasms show foci of sebaceous differentiation, with the majority of the tumor representing a recognizable salivary gland neoplasm.
Management and Prognosis
- •
Excision of sebaceous hyperplasia and adenoma is curative. Very rarely, sebaceous carcinomas arise in the oral cavity.
Clinical Findings
- •
Fordyce granules: these are usually noted in adults, present in up to 60% of the population, and appear as 1- to 3-mm yellowish papules, frequently located on the posterior buccal mucosa and vermilion of the lips, but they may be seen at any site. They are usually bilateral and symmetric ( Fig. 2.7 ).
FIG 2.7 Fordyce granules. (A) Yellow papules on the left buccal mucosa. (B) Yellow papules on the upper vermilion. - •
Sebaceous hyperplasia and adenoma: these are larger, yellowish papules and nodules seen at the same sites as Fordyce granules.
- •
Sebaceous choristoma: these are papules or nodules usually located in the midline of the tongue in the area of the foramen cecum.
Etiopathogenesis and Histopathologic Features
Fordyce granules are considered normal structures in the mouth. They can become hyperplastic and adenomatous. Patients with Muir-Torre syndrome who present with skin sebaceous tumors and internal malignancy have a high prevalence of sebaceous hyperplasia.
- •
Fordyce granules: these consist of mature sebaceous glands with a single germinative layer and may or may not open onto the mucosa via a duct lined by squamous epithelium. Sebocytes have central nuclei and vacuolated cytoplasm. Hair and Demodex folliculorum have been reported ( Fig. 2.8 ).
FIG 2.8 Fordyce granules: two sebaceous glands in the lamina propria. - •
Sebaceous hyperplasia: this consists of at least 15 sebaceous lobules (this number is somewhat arbitrary) opening into a central duct lined by squamous epithelium ( Fig. 2.9 ). The duct may become cystically dilated ( Fig. 2.10 ).
FIG 2.9 Sebaceous hyperplasia. (A) Many lobules of sebaceous glands in the lamina propria without hyperplasia of the germinative layer. (B) Mature sebocytes, secretions within the duct and no proliferation of germinative cells.
FIG 2.10 Sebaceous hyperplasia. (A) Lobular proliferation of sebaceous glands with ducts opening into the oral cavity. (B) Cystically dilated ducts and mature sebocytes. - •
Sebaceous adenoma: this consists of many sebaceous lobules with proliferation of germinative basaloid cells at the periphery of the lobules.
Differential Diagnosis
- •
Some salivary gland neoplasms show foci of sebaceous differentiation, with the majority of the tumor representing a recognizable salivary gland neoplasm.
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