Psammomatoid ossifying fibroma

Excerpt

A 26-year-old right-handed African-American woman, who began noticing visual changes and blind spots of her right eye for over a year. She complained of diplopia and her depth perception was off. Prior to admission she also began noticing vertigo, nausea as well as some word-finding difficulties. Examination revealed right proptosis. A CT scan disclosed a large mass in the right sphenoid sinus, extending into the right orbit and into the anterior cranial fossa (A). Evaluation of trans-sphenoidal biopsy showed a concentrically arranged lesion (B) composed distinct layers of fibro-osseus tissue. The central zone (asterisk on B) contained deeply basophilic on hematoxylin and eosin and oval shaped “pebble stone”-like inclusions with distinct layering rendering a “psammomatoid” appearance (arrowheads on D). They were found in a close juxtaposition to similarly ovoid but more eosinophilic osteoid (D) with apparent transitional forms, suggesting a genetic relationship between twos. The psammomatoid ossicles rested in a background of densely cellular fibroblastic proliferation composed of uniform spindle cells. The central nidus of predominantly oval and small ossicles was surrounded by a rim of much bulkier and more rectangular nascent bony trabeculae with a paucity of osteoblasts. Additionally, there were foci of spindle cells within loose basophilic matrix, lacking osteoid formation (C). The lesion was surrounded by a reactive bone (arrow on C, bars: 200 μ). The lesion is known as psammomatoid (juvenile) ossifying fibroma, a benign but locally recurring lesion with a known affinity to frontal, ethmoid bones and maxilla of young. …