[Increased neuron-specific enolase levels in patients with long-standing pyothorax-associated lymphoma]

A 78-year-old man was admitted for the evaluation of chest pain and a subcutaneous giant mass in the left chest, which had been growing for 3 months. A computed tomogram of the chest revealed a giant tumor attached to the parietal pleura with calcification of long-standing pyothorax. Pathological findings of a specimen obtained from this tumor showed diffuse proliferation of large atypical lymphocytes with 1-2 nucleoli and abundant cytoplasm. In immunohistochemical studies, tumor cells stained positive for CD20 but not for CD45 RO. The diagnosis was long-standing pyothorax-associated lymphoma (diffuse large-cell lymphoma, B-cell type). The patient's serum neuron-specific enolase (NSE) level was 101 ng/ml on admission, and declined in tandem with a chemotherapy-induced decrease in tumor size. In addition, immunohistochemical studies showed staining of tumor cells by anti-NSE polyclonal antibody. Although rarely observed in patients with malignant lymphoma, increased serum NSE levels may serve as an index of chemotherapeutic effectiveness.