[A case of CD56 positive T-cell lymphoma originating from mediastinal lymph nodes]

The patient, a 63-year-old man was admitted to our hospital with complaints of high-grade fever and left chest pain. The chest X-ray film taken on admission showed the presence of pleural effusion. The chest CT scan revealed left mediastinal enlargement. Examination of the pleural effusion showed a high concentration of adenosine deaminase (ADA) and the cytological examination showed no malignancy. We diagnosed pleuritis tuberculosa. His general condition worsened in spite of anti-tuberculosis therapy and soluble interleukin-2 receptor (sIL-2R) was elevated. The video-assisted thoracoscopic biopsy was negative. Soon after that the lymph nodes from the left supraclavicular region to the mediastinum became swollen. The diagnosis of peripheral T-cell lymphoma, unspecified (WHO classification) with CD56 expression, was established based on the results of lymph node biopsy and pleural effusion cytology. He was treated with cyclophosphamide/doxorubicin/vincristine/prednisolone (CHOP) chemotherapy. Since two courses of chemotherapy were not effective we changed to carboplatin/ifosfamide/ etoposide/dexamethasone (DeVIC) chemotherapy. His condition improved and a complete response was obtained. In conclusion, the presence of a high level of ADA in the pleural effusion and resistance to anti-tuberculosis therapy should suggest a malignant lymphoma.