AGGRESSIVE PSAMMOMATOID OSSIFYING FIBROMAS OF THE SINONASAL REGION - A CLINICOPATHOLOGICAL STUDY OF A DISTINCT GROUP OF FIBROOSSEOUS LESIONS

Background. Psammomatoid ossifying fibromas represent a unique subset of fibro-osseous lesions of the sinonasal tract. They have distinctive histomorphologic features and a tendency toward locally aggressive be havior, including invasion and destruction of adjacent anatomic struct ures. Methods. Seven cases of psammomatoid ossifying fibromas of the s inonasal tract were identified in the files of the Otolaryngic Tumor R egistry at the Armed Forces Institute of Pathology, Medical records, i ncluding the clinical history, location of the lesions, radiographs, t reatment, and follow-up were reviewed in each case. Follow-up informat ion was available in all of the cases. Results. Four of the patients w ere male and three were female. The patients' ages ranged from 5 to 54 years (median age, 33 years). Symptoms included facial swelling, nasa l obstruction, pain, sinusitis, headache, and proptosis. Radiographic studies confirmed the presence of an osseous and/or soft tissue mass v arying in appearance from well demarcated without invasion or erosion to invasive with bone erosion and intracranial extension. Sites of inv olvement included the nasal cavity and all paranasal sinuses, particul arly the ethmoid and maxillary sinuses, Often, more than one sinus was involved and extension of disease included involvement of the orbit, nasopharynx, palate, and anterior cranial fossa. The histologic appear ance was characterized by the presence of small mineralized (psammomat oid) bodies admired with a cellular stroma with a variable amount of m yxomatous material and scattered giant cells. Confusion with other oss eous and soft tissue tumors may occur resulting in too limited or too aggressive management. En bloc surgical excision is the treatment of c hoice and may prove curative. Aggressive behavior with recurrence(s) o r invasion into adjacent structures occurred. At the time of this writ ing, the patients are alive over follow-up periods ranging from 6 mont hs to 7 years. Conclusions. Gnathic and midfacial fibro-osseous prolif erations are a diverse group of lesions. A subset of these fibro-osseo us lesions with predilection for the sinonasal tract were identified. These lesions are characterized by their distinctive histology, includ ing psammomatoid ossicles and their locally aggressive growth. Complet e surgical removal is the treatment of choice.