22 year old woman with recent onset of painful breast mass
Diagnosis: Nodular fasciitis
Discussion: This is a classic presentation of nodular fasciitis; rarely do patients remember associated trauma. Usually nodular fasciitis affects the trunk or forearm; involvement of the breast is uncommon. The bland spindled cells are arranged in swirling fascicles, and the associated edematous/myxoid stroma gives the appearance of cells in tissue culture. Nodular fasciitis should resolve over a few months, and excision is not necessary.