We report a case of unusual B-cell malignant lymphoma of the kidney and mediastinum. Renal biopsy showed prominent myxoid changes and sarcomatous features, leading to considerable difficulty in histologic diagnosis on routinely stained histologic sections. However, immunohistochemical staining for lymphocyte markers led to the final histologic diagnosis of B-cell malignant lymphoma. Although myxoid change is not generally found in malignant lymphoma, malignant lymphoma should not be excluded from consideration when one encounters a small round cell sarcoma with myxoid stroma, especially in extranodal soft tissue tumors.
(Internal Medicine 32: 139- 144, 1993)
The Japanese Society of Internal Medicine