Intradermal Proliferative Fasciitis Occurring With Chondrodermatitis Nodularis Helicis.

Nodular fasciitis is a benign myofibroblastic tumor. Its uncommon variant, proliferative fasciitis (PF), can present in an even less common intradermal form. We report a case of intradermal PF of the ear in a 45-year-old man who presented with recurrent episodes of pain and swelling of the lesion. Histologic examination showed a dermal, nodular proliferation of ganglion-like basophilic fibroblasts with prominent nuclei and nucleoli, admixed with foamy histiocytes and areas of spindle cells arranged in intersecting fascicles in a fibromyxoid background. Lesional cells stained positive for smooth muscle actin and were negative for AE1/AE3, p63, and Melan-A. CD68 highlighted intervening histiocytes. We postulate that the underlying chondrodermatitis nodularis helicis was a triggering etiology, consistent with the current speculation that intradermal PF results from trauma.