Mycosis fungoides (MF) in deep-seated lymph nodes, spleen or liver appears to be associated with a lack of response of the disease to topical external therapy. Fourteen patients with mycosis fungoides were clinically staged and had a staging laparotomy. Mycosis fungoides was found in the lymph nodes of 3 of these patients, in the spleen in 4 and in the liver in 2 cases. Patients with adenopathy, or with splenomegaly or abnormal spleen scans, should be considered for surgical staging to determine the extent of extracutaneous disease. The documentation of extracutaneous MF becomes necessary in the development of new therapeutic approaches.