Juvenile ossifying fibroma of the jaw: a retrospective study of 15 cases

Abstract

The management of patients with juvenile ossifying fibroma (JOF) remains controversial. To explore the correlations between different treatments and the patient prognosis, 15 cases of JOF of the jaw were reviewed. Five patients were male and 10 were female. Patient age at the time of disease onset ranged from 7 to 18 years (mean 10.9 years). Nine tumours were located in mandible and six in the maxilla. These cases typically manifested clinically as painless swelling of the jaw (9/15, 60%); 40% (6/15) of the cases were associated with pain, diplopia, stuffy nose, and/or rapid growth. Images of JOF can show a radiolucent, mixed, or ground glass-like appearance. Pathological examinations revealed 10 cases of juvenile trabecular ossifying fibroma (JTOF) and five cases of juvenile psammomatoid ossifying fibroma (JPOF). In terms of the treatment plan, six patients initially received radical surgery; nine patients underwent conservative treatment, among whom six (6/9, 66.7%) had one or more recurrence. At the end of the follow-up period, 12 patients had no evidence of tumour recurrence and three cases were alive with a tumour. In summary, surgeons should develop the surgical plan according to the extent of the lesion, relapse status, growth rate, and family choice, and these patients should be followed up closely.

Ossifying fibroma (OF) is a type of benign fibro-osseous lesion. This tumour is characterized by clear boundaries and cell-rich fibrosis, and contains varying amounts of calcified tissue resembling bone, cementum, or both. OF lesions are classified as conventional ossifying fibroma and juvenile ossifying fibroma (JOF). Conventional OF is mainly seen in adults. JOF usually occurs in children or adolescents, and it is therefore also known as juvenile active/aggressive ossifying fibroma (JAOF). In 2005, the World Health Organization (WHO) noted that the age at onset of JOF is 15 years and younger. However, JOF has also been documented in adults.

JOF has characteristics of aggressive growth, is associated with damage to the cortical bone, and may involve the nasal cavity, eyes, and even cerebrum. However, there are no reports of cases of malignant transformation or metastasis. The imaging characteristics of JOF show expansive, well-defined radiolucent or mixed images that are separated from the surrounding normal bone. Based on histopathology, JOF is divided into the following two subtypes: juvenile psammomatoid ossifying fibroma (JPOF) and juvenile trabecular ossifying fibroma (JTOF). In addition, JOF usually contains multinucleated giant cells, whereas conventional OF does not. Conventional OF usually presents as a slow-growing mass of bone expansion that is usually without symptoms and rarely recurs; conversely, 38.5% of JOF cases are associated with mandibular swelling and pain and there may be short-term rapid growth. Therefore, surgeons should consider clinical features, radiological characteristics, and pathological features when diagnosing JOF. Key points to be considered include age, status of growth, and histopathology.

The management of patients with JOF remains controversial. According to the literature, the recurrence rate after surgery is approximately 30–58%. Therefore, designing an appropriate treatment plan for the JOF patient could help to improve the prognosis and quality of life. Depending on biological behaviour and the lesions involved, treatment can be conservative or radical. Some researchers have emphasized the aggressive growth characteristics and high recurrence rate of JOF, leading them to advocate local radical surgery. In contrast, others consider that conservative treatment is more beneficial for young patients when taking into account their growth and development, their appearance, and the preservation of chewing and nerve functions.

This study was performed to review the clinical features, imaging features, and pathological characteristics of 15 cases of JOF treated at the authors’ institution. The relationships between the different treatment options and the prognosis are discussed and the most suitable treatments for JOF are explored.

Materials and methods

A total of 15 patients with JOF treated between 2005 and 2014 in the Department of Oral and Maxillofacial–Head and Neck Oncology of the study institution were included. Each patient’s medical history was reviewed carefully to collect clinical data (including age, sex, disease location, symptoms, surgical approach, and prognosis), radiological features, histological type, and other information.

According to the anatomical location, the mandible was divided into anterior (left canine to right canine), posterior (first premolar to third molar), angle, ramus, and condyle. The maxilla was divided into anterior (left canine to right canine) and posterior (first premolar to the maxillary tuberosity). Imaging data were used to analyze the lesion and surrounding tissue boundaries and the internal radiographic architecture. The internal radiographic architecture was divided into mixed radiopaque and radiolucent, unilocular or multilocular radiolucency, and ground glass opaque. An oral pathology specialist classified the histological subtype as either JTOF or JPOF based on the 2005 WHO classification criteria for head and neck cancer. Surgeries performed included conservative treatments (curettage and enucleation) and radical surgery (complete resection with or without reconstruction).

Due to the retrospective nature of this study, it was granted an exemption from requiring ethics approval in writing by the institutional review board of the study hospital.

Results

Clinical data

Of the 15 cases of JOF, five were male and 10 were female, giving a male to female ratio of 1:2. The age at onset ranged from 7 to 18 years (mean 10.9 years). The ages of JTOF patients ranged from 9 to 13 years (mean 11 years) and the ages of JPOF patients ranged from 7 to 18 years (mean 10.9 years). The disease duration ranged from 2 weeks to 5 years, with an average of 18.2 months ( Table 1 ).

Table 1
Clinical information, treatment, and follow-up information for the 15 cases of juvenile ossifying fibroma (JOF).
Patient No./sex Age at onset (years) Age at operation (years) Size Symptoms Location Surgery Follow-up (months); outcome
Conservative treatment
1/M 8 8 4.5 × 4 Swelling Right maxilla Curettage 72; alive with tumour
2/F 14 19 2 × 1.5 Swelling Left maxilla (posterior) Curettage 20; alive with tumour
3/M 13 13 5 × 4 Swelling Right mandible (posterior) Enucleation 38; NED
4(R)/M 18 20 3 × 2 Swelling, pain Left maxilla Curettage 124; alive with tumour
5(R)/F 9 16 6 × 4 Swelling Right mandible (posterior) Curettage/resection + fibula 95; NED
6(R)/F 12 15 5 × 4 Swelling Left mandible (posterior/angle) Curettage/resection + iliac crest 146; NED
7(R)/M 15 17 9 × 8 Swelling, rapid growth Right mandible (posterior) Curettage/resection + fibula 105; NED
8(R)/M 10 12 10 × 7 Swelling, rapid growth Left mandible Curettage/resection + fibula 40; NED
9(R)/F 9 19 9 × 8 Swelling, stuffy nose, diplopia Right maxilla Curettage/resection + fibula 128; NED
Radical treatment
10/F 13 19 12 × 8 Swelling Left mandible (posterior) Resection + fibula 87; NED
11/F 11 11 6 × 4 Swelling Right mandible (posterior) Resection + iliac crest 58; NED
12/F 7 7 6 × 4.5 Swelling Left mandible (posterior/angle) Resection + iliac crest 36; NED
13/F 7 7 3 × 2 Swelling Right mandible (condyle) Resection + costal cartilage 15; NED
14/F 7 8 4 × 3.5 Swelling, pain, diplopia, rapid growth Left maxilla (posterior) Resection 18; NED
15/F 11 15 6 × 4 Swelling, pain, rapid growth Right maxilla Resection 13; NED
F, female; M, male; NED, no evidence of disease; (R), recurrence.

The lesions were located in the mandible in nine cases and in the maxilla in six cases, with three involving the maxillary sinus. In mandibular cases, the site was most often posterior (5/9, 55.6%), followed by a combination of posterior and angle (2/9, 22.2%). For the upper jaw, unilateral involvement of the entire maxilla (4/6, 66.7%) was most common, followed by the posterior of the maxilla (2/6, 33.3%).

Sixty percent (9/15) of cases manifested clinically as a slowly growing painless mass in the jaw. Forty percent of cases (6/15; four cases involving the maxilla and two involving the mandible) presented with pain, diplopia, stuffy nose, and/or rapid growth. Clinical examination revealed an immobile hard mass, and egg shell crackling was occasionally noted when a cystic lesion developed.

Before surgery, most patients had a diagnosis of ossifying fibroma (10/15, 66.7%). Other diagnoses included ameloblastoma ( n = 2, 13.3%), fibrous dysplasia ( n = 1, 6.7%), chondromyxoid fibroma ( n = 1, 6.7%) and aneurysmal bone cyst ( n = 1, 6.7%).

Imaging features

Images of all patients showed a mass with clear boundaries. There was generally no soft tissue involvement. Computed tomography (CT) and/or panoramic images were available for a total of 13 patients. According to the component and proportion of soft tissue and hard tissue in the internal structure, the tumour masses presented as mixed radiopaque and radiolucent (5/13, 38.5%), unilocular or multilocular radiolucency (3/13, 23.1%), and ground glass opaque (4/13, 30.8%) ( Table 2 ). Three of the ground glass opaque cases were associated with central radiolucent regions ( Fig. 1 ), and one case had multiple radiolucent regions associated with ground glass plaques. CT imaging and three-dimensional reconstruction of the different orientations showed cortical bone destruction and absorption in nine cases (9/13, 69.2%), with adjacent tooth or root displacement in seven (7/13, 53.8%).

Table 2
Radiographic features and pathology of 15 cases of juvenile ossifying fibroma (JOF).
Pathology Patient No. Radiographic features
JTOF 4 Ground glass opaque, well-defined border
6 Mixed radiopaque and radiolucent, well-defined border
7 Multilocular radiolucency, well-defined border
11 Mixed radiopaque and radiolucent, well-defined border
1 Mixed radiopaque and radiolucent, well-defined border
12 Unilocular radiolucency, well-defined border
8 * Multilocular radiolucency, well-defined border
2 Not available
13 Mixed radiopaque and radiolucent, well-defined border
14 * Not available
JPOF 10 Ground glass opaque with central radiolucency, well-defined border
3 Mixed radiopaque and radiolucent, well-defined border
5 Ground glass opaque with central radiolucency, well-defined border
9 Multilocular radiolucency with ground glass opaque, well-defined border
15 Ground glass opaque with central radiolucency, well-defined border
JTOF, juvenile trabecular ossifying fibroma; JPOF, juvenile psammomatoid ossifying fibroma.

* JTOF with aneurysmal bone cyst.

Fig. 1
Imaging findings in juvenile ossifying fibroma (JOF): case 15. (A) Preoperative axial CT showing a bulging mass in the maxilla, a ground glass-like appearance, and central cystic changes. (B) Preoperative sagittal CT showing a mass intruding into the maxillary sinus and root displacement. There is a high-density shadow in the surrounding area.

Histopathological features

General examination revealed that JOF was usually a grey mass with a clear boundary. Tumour sizes ranged from 2 to 12 cm, with an average of 6.03 cm. Those with diameters ≥5 cm accounted for 66.7% (10/15) of cases. Dissection of the tissue showed gravel-like or hard tissue. Of the 15 cases of JOF, 10 were JTOF and five were JPOF ( Table 2 ). Under the microscope, JTOF demonstrated a cell-rich fibrous tissue background with a strip of osteoid-containing cells or immature trabecular cells. The trabecular bone was surrounded by a layer of hypertrophic osteoblasts, which together formed a grid-shaped region. Some regions showed aggregations of osteoclast-like multinucleated giant cells. Twenty percent (2/10) of cases were associated with an aneurysmal bone cyst ( Fig. 2 A, C ). JPOF was characterized by fibroblastic stroma and basophils containing sand-like structures that resembled cementum ( Fig. 2 B).

Fig. 2
Histopathological features of juvenile ossifying fibroma (JOF). (A) Juvenile trabecular ossifying fibroma (JTOF) (case 4) has a cell-rich fibrous tissue background with cell-containing immature trabecular bone. A layer of hypertrophic osteoblasts, which form a grid-like structure, surrounds the trabecular bone. (B) Juvenile psammomatoid ossifying fibroma (JPOF) (case 15) has a fibrous stroma containing spherical mineralized bodies. The bodies are like cementum, with basophilic cores and an eosinophilic exterior. (C) Aneurysmal bone cyst formed within JTOF (case 8). The capsule is filled with red blood cells.

Types of surgery and prognosis

All patients underwent surgical treatment, including conservative treatment and local radical surgery. Nine patients first underwent conservative treatment, among whom six had one or more recurrence, giving a recurrence rate of 66.7% (6/9). Among those experiencing a recurrence, five underwent local radical surgery and one underwent local curettage. Cases 4, 5, 6, and 7 had recurrence after 8 months, 2 years, 6 months, and 11 months, respectively. Case 8 had local recurrences after twice undergoing curettage, at 6 months and 7 months after the procedure. Case 9 had recurrences at 5 years and 15 months after surgeries. Overall, recurrence occurred at between 6 months and 5 years, with an average of 17.1 months. Six patients initially had local radical surgery and none had a recurrence.

Nine patients underwent reconstructive surgery. One patient with JOF in the maxilla underwent a fibula muscle flap transplantation ( Fig. 3 ). Of the eight mandible cases, three underwent a free iliac crest graft ( Fig. 4 ), one case with condyle involvement had a costal cartilage transplantation ( Fig. 5 ), and four cases underwent fibula flap transplantation ( Fig. 6 ).

Jan 16, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Juvenile ossifying fibroma of the jaw: a retrospective study of 15 cases
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