[CD56- and CD4-positive non-Hodgkin's lymphoma of probable T-cell origin]

A 65-year-old man was admitted with swelling of the right neck and bilateral inguinal lymph nodes. Endoscopic examination revealed no nasal infiltration. Pathological examination of a neck lymph node biopsy specimen revealed peripheral T-cell lymphoma according to the Revised European-American Classification of Lymphoid Neoplasms (REAL). The phenotype of the lymphoma cells was CD56+, CD16-, CD2+, surface CD3-, cytoplasmic CD3+, CD4+, CD8-, CD5+, CD7- and CD45RO+. May-Giemsa staining demonstrated no azurophilic granules in the lymphoma cells. Immunohistopathologic examination showed negativity for TIA-1 and granzyme B, and rearrangement of the TCR C beta 1 gene was also noted. These findings strongly suggested that this was a T-cell lymphoma. The patient received 8 courses of CHOP chemotherapy plus sobuzoxane. This led to a marked decrease of lymph node swelling, and currently the patient is still in remission. According to the REAL classification, T/NK-cell lymphomas are included among the peripheral T cell tumours, and seem to constitute a heterogeneous group of neoplasms. Although some cases of CD4+ CD56+ lymphoma have been reported, the present case appears to be the first example to show TCR gene rearrangement and negativity for TIA-1 and granzyme B. Since the classification of T/NK-cell lymphoma is still controversial, accumulation of such cases may help to better define T/NK-cell neoplasms.