A Rare Case of Ossifying Fibroma with Cystic Degeneration: Diagnostic Challenge with Literature Review

Abstract

Cystic degeneration can occur with various bone lesions. These non-epithelial lined cysts vary from aneurysmal bone cyst, solitary bone cyst or non specific cystic degeneration. In jaws, this association is not well documented. In literature only three cases have been reported as ossifying fibroma (OF) with cystic degeneration. This case appears to be the fourth case to highlight non specific cystic changes in OF. We report a case of OF in 23 year old female with asymptomatic swelling over the left side of face for the past 3 years involving the maxilla, maxillary sinus as well as nasal cavity. Histopathology revealed it to be OF complicated by non-specific cystic degeneration. OF of jaws is an odontogenic neoplasm arising from tooth bearing areas. It occurs more commonly in women in posterior mandible region. Microscopically it shows variable mixture of osteoid bone and basophilic acellular spherules while bony trabeculae frequently demonstrate both woven and lamellar patterns. Various pathogenesis have also been highlighted behind the cystic degeneration’s in bony lesions. A review is also tabulated of OFs with cystic degenerations in the jaws reported in the past.

Introduction

The fibro-osseous lesions (FOLs) of jaws comprise a diverse and challenging group of conditions leading to difficulty in classification and treatment. They are characterized by replacement of normal bone by collagen fibers and fibroblasts that contain varying amounts of mineralized substance, which may be bony or cementum- like in appearance [1]. Ossifying Fibroma (OF) coined by Montgomery is a benign odontogenic tumor of mesenchymal origin is an encapsulated lesion made of fibrous tissue containing variable amounts of mineralized material resembling bone and/or cementum [2]. Other common FOLs of the jaws are fibrous dysplasia, focal cemento-osseous dysplasia, periapical cemento-osseous dysplasia and florid cemento-osseous dysplasia [3]. It’s preferred site of occurrence is reported to be mandible varying from 70 to 89% of cases and in maxilla 11–26% with affinity for premolar and molar area. The maxillary lesions were found to be more aggressive [2]. OF develops more in females than males with a peak incidence during third and fourth decades [4]. Goaz and White reported that when OF occurs in maxilla, it is most commonly located in the canine fossae and zygomatic arch. It may grow to completely fill the maxillary sinus [2]. Non epithelial lined cysts occasionally occur along with various bone lesions mainly fibrous dysplasia, giant cell tumor, chondroblastoma, ossifying fibroma, benign osteoblastoma, cemento-osseous dysplasia, fibrous histiocytoma, fibrosarcoma and osteosarcoma [5]. These cysts vary from aneurysmal bone cyst (ABC), simple bone cyst (SBC) and non specific cystic degeneration. In the jaws this association is not well documented but non epithelial cysts have been described in association with fibrous dysplasia, OF, and cemento-osseous dysplasia [5]. Through this paper we tend to highlight a case of OF complicated by non specific cystic degeneration. In literature only three cases have been reported with similar diagnosis [8–10] (Table 1). This case appears to be the fourth case to highlight non specific cystic changes in OF.

Table 1.

Previous cases of ossifying fibroma associated with cystic degeneration in the jaws in comparison with present case

Sr. No.	Authors	Age/sex	Site	Radiographic appearance	Histopathology	Complications
1.	Boyd, Robert et al. (1979)	27/M	Right side posterior maxilla	Radiolucent	Many blood-filled spaces and capillaries separated by fibrous tissue which contained thin strands of calcified woven bone. In other areas the bony element was much more evident and produced a fibro-osseous pattern of the ossifying fibroma type	OF with secondary Aneurysmal bone cyst
2.	Gnanadeepam et al. (2012)	25/F	Left side posterior mandible	Radiolucent	Fibrocellular stroma with immature bone trabeculae and enveloped by a thin, loose fibrous capsule. A non-specific diagnosis of fibro-osseous lesion was rendered	OF with secondary Simple bone cyst
3.	Nasim et al. (2016)	11/M	Left side posterior maxilla	Radiolucent	Cavernous spaces filled with erythrocytes surrounded by fibroblastic stroma, bony trabeculae and woven bone	OF with secondary Aneurysmal bone cyst
4.	Our case (2018)	23/F	Left side anterior maxilla	Radiolucent	Fibrocellular connective tissue stroma with presence of bony trabeculae and woven bone formation. Central area of stroma shows cystic degeneration with presence of chronic inflammatory cells. In few areas cystic cavity shows epithelisation with presence of non keratinised stratified squamous epithelium	OF with secondary non specific cystic degeneration

Case Report

A 23-year-old female presented to OPD with swelling over the left side of face since 2 years, which developed mild pain since past 2 months. Her past medical, dental and family history was not significant. There was no history of traumatic episode. Extra oral swelling on left side of face extended from anterior maxilla to lateral border of nose anteriorly and lateral canthus of eye posteriorly and from infraorbital margin superiorly to 1 cm above angle of mouth inferiorly (Fig. 1a). Intra oral examination showed vestibular obliteration with respect to second quadrant. Radiographic findings suggested well defined expansile lytic lesion with internal septations in alveolar maxilla and hard palate extending in maxillary sinus medially projecting into nasal cavity leading to mild deviation of nasal septum (Fig. 1b, c).

Fig. 1.

a: Clinical photograph depicting extra oral swelling over left side of face; b: coronal section showing lytic lesion; c: sagittal section reveals internal septations; d: photograph of resected specimen showing well-defined cystic lumen

FNAC revealed presence of straw colored fluid in the cystic cavity. Based on site of lesion and radiographic findings a provisional diagnosis of Adenomatoid Odontogenic Tumor was made. Differential diagnosis included odontogenic keratocyst, calcifying epithelial odontogenic tumor and OF.

An incisional biopsy was performed and histopathology revealed fibro cellular connective tissue stroma with abundant bone formation in form of woven bone and osteoid tissue leading to diagnosis of OF (Fig. 2a). Based on anatomical location, large size and histopathological report of OF, surgical excision was performed with the goal to eradicate pathology, prevention of recurrence and to restore form, function and esthetics of the patient.

Fig. 2.

a–c: Photomicrograph of tissue sections showing abundant bony trabeculae and bone formation in capsule (a, b: H & E/4X; c: H & E/10X); d: Photomicrograph (H & E-4X) depicting the epithelialization of cystic cavity lined by non-keratinized stratified squamous epithelium

After excision it was sent for histopathological evaluation, which on gross examination was cystic in appearance (Fig. 1d). Excisional biopsy revealed fibro-cellular connective tissue stroma with presence of bony trabeculae and woven bone in abundance. Central area of stroma showed cystic degeneration epithelization of the cavity in few areas (Fig. 2b–d). This lead to a final diagnosis of OF with non specific cystic degeneration. The patient is on follow up since 2 years and has shown no signs of recurrence.

Discussion

The clinical presentation of OF is usually asymptomatic when lesions are diagnosed in younger subjects, while cortical expansion and pain may ensue in elderly. They are characterised by variable radiographic patterns. OF with a completely radiolucent lesion may be misdiagnosed as cement-osseous dysplasia, odontogenic cyst, periapical granuloma, ameloblastoma, central giant cell granuloma. Differential diagnosis for mixed radiographical features may include a non specific diagnosis of FOL, calcifying odontogenic cyst, adenomatoid odontogenic tumor, calcifying epithelial odontogenic tumor. The primary pathogenesis of non epithelial lined bone cysts remains unknown [5]. Non specific cyst degeneration is the term given to those cystic lesions that do not meet histological criteria of either an ABC or SBC [6]. However probable reason postulated for ABC is intramedullary hemorrhage with direct circulatory connection with hematoma, whereas complete interruption of blood supply leads to SBC but unlike both, non specific cystic degeneration does not appear as a primary phenomenon [7]. This suggests that other factors may be involved in the pathogenesis. In our case epithelisation of the cyst was evident, the probable reason for which may be increased cystic pressure due to long standing swelling and close approximation to maxillary sinus or buccal mucosa which might have lead to secondary epithelisation. The development of cyst degeneration may cause considerable expansion with functional and cosmetic problem that requires an early surgical intervention. The literature showed that depending on nature and extent of individual lesions the modalities for management of FOLs vary from simple observation to surgical enucleation or resection. FOLs with concomitant SBC or cystic degeneration require aggressive measures, as in the present case [8]. This case stands out due to unusual presentation in maxilla and histopathological variation showing cystic degeneration with secondary epithelisation. Peculiarity of this case was that pre-op diagnosis was Adenomatoid Odontogenic Tumor based on site of presentation and radiological findings but histopathology report confirmed it as OF with non specific cystic degeneration.

Conclusion

A case of OF with extensive cystic degeneration is hereby reported, the diagnosis of which required proper integration of clinical, radiological, histological and gross surgical features. OF’s should also be kept in mind in lesions associated with anterior maxilla along with odontogenic tumors. Prompt and early surgical intervention is mandatory as cyst degeneration may cause considerable expansion with functional and cosmetic problems.

Compliance with Ethical Standards

Conflict of interest

The authors declare that they have no conflict of interest.