What is nodular fasciitis?

Nodular fasciitis (pseudocarcinomatous nodular fasciitis) is a rare, benign, fibroblastic tumor that many consider to be a pseudoneoplastic or reactive growth. It may occur at any age but most commonly presents in young adults as a solitary, rapidly growing, subcutaneous nodule on the extremities. The nodule may be painful, is typically 1 to 3 cm in size, and may adhere to the underlying fascia. Simple excision is curative, but untreated lesions have been documented to regress spontaneously. The importance of this lesion is that, histologically, it may be confused with malignant fibrous neoplasms, because the fibroblasts are large and pleomorphic and mitotic figures are relatively common.