Beta-catenin positive nodular fasciitis-like lesion of the maxilla

Abstract

A 14-month-old boy presented with a palpable swelling of his left anterior maxilla. Computed tomography (CT) scan showed a 2 cm circumscribed expansile lesion (cystic +/– soft tissue component) in the anterior maxilla. A review of the radiology showed that the lesion was separate from the dental apparatus and was of intermediate aggression. Light microscopy of the biopsy revealed an intraosseous circumscribed proliferation of bland spindle cells set in a fibromyxoid stroma with occasional extravasation of red blood cells. Immuno-histochemically, the tumour cells showed positive staining for vimentin, and both nuclear and cytoplasmic expression for β-catenin. The features were of a nodular fasciitis-like lesion that was β-catenin positive. The patient is doing well, with no clinical or radiological evidence of recurrence 1 year post-operatively. Cranial nodular fasciitis-like lesions are relatively uncommon and are thought to be a post-traumatic reactive process. A recent study has shown that a subset of these lesions have dysregulation of the Wnt/β-catenin pathway, suggesting that they maybe pathobiolo-gically related to fibromatoses. A few cases have been associated with familial adenomatous polyposis (FAP). Testing for FAP has been recommended for this child.