[A case of primary malignant lymphoma of the pararectal space]

A 16-year-old man presented with lumbago, perianal pain and constipation. A large tumor was palpable by digital rectal examination. Then, transrectal needle biopsies of the tumor were performed. Histopathological diagnosis was non-Hodgkin's malignant lymphoma (diffuse large B-cell type according to the new WHO classification). The results of some examinations were compatible with the diagnosis of primary lymphoma of the pararectal space. The patient underwent 2 courses of combination chemotherapy CHOP (consisting of cyclophosphamide, doxorubichin, vincristine, and prednisolone), and high-dose chemotherapy (ranimustine, etoposide, ifosfamide) with peripheral blood stem cell transplantation. After high-dose chemotherapy, radiation therapy was performed since there was a possibility of residual tumor, and complete remission was achieved. Now, 12 months after completion of the radiation, he remains free of the disease. This is probably the first clinical case of malignant lymphoma of the pararectal space ever reported in the Japanese literature.