ANTHRACOTIC AND ANTHRACOSILICOTIC SPINDLE-CELL PSEUDOTUMORS OF MEDIASTINAL LYMPH-NODES - REPORT OF 5 CASES OF A REACTIVE LESION THAT SIMULATES MALIGNANCY

We report five cases of reactive mediastinal spindle cell proliferatio ns associated with anthracosis and anthracosilicosis that simulated a malignant profess both on clinical and morphological grounds. Clinical ly; the lesions formed radiographically evident masses or were infiltr ative. Microscopically, a prominent storiform pattern of intertwining spindle cells was found in four cases. This proliferation extended out side of the lymph node capsule in three cases and surrounded nerves in two. Because of this combination of features, the submitted diagnoses included a malignant neoplasm in four cases. The spindle cells were i mmunoreactive for histiocytic markers and focally contained fine anthr acotic pigment. All eases featured nodular hyaline scars and contained polarizable material suggestive of silica, although a history of indu strial exposure was obtained in only two cases. No lesion has enlarged or otherwise progressed during follow-up ranging from 6 to 48 months. The differential diagnosis includes a variety of spindle cell neoplas ms, including malignant fibrous histiocytoma, follicular dendritic cel l tumor, spindle cell melanoma, and Kaposi's sarcoma. Copyright (C) 19 98 by W.B. Saunders Company.