Natural killer/T cell lymphoma initiating with pleural effusion: the significance of MICM combined techniques for the diagnosis.

Natural killer (NK)/T-cell lymphomas represent a rare type of lymphoma derived from either activated NK cells or cytotoxic T cells. They are most commonly extranodal and tend to present as destructive lesions within the midline facial structures. Other than the nasal cavity and Para nasal sinuses, several other extra nodal sites of involvement have been reported, including the pharynx, gastrointestinal tract, and testis. Occasionally, pleural effusion has also been observed. Here, a case of lymphoma of NK/T-cell type presented as pleural effusion was reported. The patient was previously misdiagnosed as B cell non-Hodgkin's lymphoma by pathological and immunohistochemistry (IH) analysis for pleural membrane biopsy specimen. After the analysis of the pleural fluid cells by a combination of morphologic, immunophenotypic, cytogenetic and molecular (MICM) methods in Beijing Dao-Pei hospital, some lymphoblasts were found morphologically, which expressed cytoplasmic CD3 (cCD3) and CD56 by flow cytometry analysis and had a clonal T-cell receptor gamma (TCR-gamma) gene rearrangement by molecular analysis, so that the diagnosis was finally corrected as NK/T-cell lymphoma and an allogeneic stem cell transplantation was successfully performed. In conclusion, this unusual case highlights the significance of MICM combined techniques for the diagnosis of lymphoma, as well as an unusual presentation of a rare disease and the successful treatment.