A giant peripheral ossifying fibroma of the maxilla with extreme difficulty in clinical differentiation from malignancy: a case report and review of the literature.

BACKGROUND: Peripheral ossifying fibroma is a nonneoplastic inflammatory hyperplasia that originates in the periodontal ligament or periosteum in response to chronic mechanical irritation. Peripheral ossifying fibroma develops more commonly in young females as a solitary, slow-growing, exophytic nodular mass of the gingiva, no more than 2 cm in diameter. While various synonyms have been used to refer to peripheral ossifying fibroma, very similar names have also been applied to neoplastic diseases that are pathologically distinct from peripheral ossifying fibroma, causing considerable nomenclatural confusion. Herein, we report our experience with an unusual giant peripheral ossifying fibroma with a differential diagnostic challenge in distinguishing it from a malignancy. CASE PRESENTATION: A 68-year-old Japanese male was referred to our department with a suspected gingival malignancy presenting with an elastic hard, pedunculated, exophytic mass 60 mm in diameter in the right maxillary gingiva. In addition to computed tomography showing extensive bone destruction in the right maxillary alveolus, positron emission tomography with computed tomography revealed fluorodeoxyglucose hyperaccumulation in the gingival lesion. Although these clinical findings were highly suggestive of malignancy, repeated preoperative biopsies showed no evidence of malignancy. Since even intraoperative frozen histological examination revealed no malignancy, surgical resection was performed in the form of partial maxillectomy for benign disease, followed by thorough curettage of the surrounding granulation tissue and alveolar bone. Histologically, the excised mass consisted primarily of a fibrous component with sparse proliferation of atypical fibroblast-like cells, partly comprising ossification, leading to a final diagnosis of peripheral ossifying fibroma. No relapse was observed at the 10-month follow-up. CONCLUSIONS: The clinical presentation of giant peripheral ossifying fibromas can make the differential diagnosis from malignancy difficult. Proper diagnosis relies on recognition of the characteristic histopathology and identification of the underlying chronic mechanical stimuli, while successful treatment mandates complete excision of the lesion and optimization of oral hygiene. Complicated terminological issues associated with peripheral ossifying fibroma require appropriate interpretation and sufficient awareness of the disease names to avoid diagnostic confusion and provide optimal management.

Noteworthy Factors to Decide Therapeutic Strategy for Carcinoma ex Pleomorphic Adenoma of Parotid Gland: A Preliminary Study Statistical Analysis of 22 Cases from Single Institution.

Carcinoma ex pleomorphic adenoma (CXPA) is a rare malignant salivary gland tumor, and its prognosis is determined by the histological progression beyond the adenoma capsule. However, a preoperative evaluation of the histological progression remains challenging, and there is no consensus regarding treatment strategies for CXPA. Herein, we aimed to predict the histological progression preoperatively and develop an appropriate treatment strategy for CXPA. We retrospectively reviewed 22 patients with parotid gland CXPA recorded at our hospital. The clinicopathological characteristics were assessed, and survival analysis was performed. T3≤ or N+ were common in widely invasive CXPA (WICXPA) (p < 0.05). A tumor diameter > 40 mm and the N+ status were associated with poor prognosis considering overall survival (OS) and locoregional recurrence rate (LRC) (p < 0.05). Patients with facial nerve paralysis exhibited better OS and LRC than those without facial nerve paralysis. More than 90% of patients with WICXPA experienced distant metastases. Meanwhile, there were no cases of recurrence or death due to intracapsular and minimally invasive CXPA. A preoperative advanced T stage or N+ status was suspected as WICXPA. Tumors > 40 mm in size and N+ status necessitate high-intensity local treatment. Facial nerve invasion can be controlled by nerve resection. Postoperative systemic therapy could control distant metastases.