Deep benign fibrous histiocytoma showing multiple metastases

Some morphological variants of benign fibrous histiocytoma (dermatofibroma) present with distinct clinical features. In particular, atypical, aneurysmal, and cellular fibrous histiocytoma are associated with a significant risk of local recurrence. Furthermore, very rarely, cutaneous fibrous histiocytoma can lead to metastatic disease. Deep benign fibrous histiocytoma is an uncommon and poorly recognized clinical subtype that arises in subcutaneous or deep soft tissue. Deep benign fibrous histiocytoma has many histologic features in common with cellular fibrous histiocytoma. Deep benign fibrous histiocytoma recurs in approximately 20% of cases and may rarely metastasize. We report a rare case of deep benign fibrous histiocytoma with metastatic potential in a 38-year-old man who presented with a 2-year history of a recurrent hard mass on his left shoulder.