Intra-articular nodular fasciitis of the proximal interphalangeal joint of a finger: A case report.

Nodular fasciitis is a benign reactive lesion, often mistaken for a soft-tissue sarcoma in clinical practice. Involvement of the finger is rare, and a finger joint even rarer. We report on the clinical, radiological and histological features of intra-articular nodular fasciitis in a 52-year-old man, originating from the proximal interphalangeal joint of the right ring finger, with cortical erosion of adjacent bone. The discussion is focused on the tumor diagnosis and therapeutic approach, the differential diagnosis and the importance of immunohistochemical staining to establish the final diagnosis.