Two cases reports of young adult nodal marginal zone lymphoma

Background : Nodal marginal zone lymphoma (NMZL) are a rare disorder, and occur in older patients (median 60 years old [y. o.]) and are extremely rare in younger patients. We report herein on the cytological and histological findings of NMZL in 2 patients less than 30 y. o. Case : Case 1, a 19 y. o. male. He complained of lymph node swelling of the neck. Aspiration cytology revealed suggestive features of histiocytic necrotizing lymphadenitis, and histologically, reactive paracortical hyperplasia had been diagnosed. The corrected diagnosis of NMZL was finalized in 2 years. Case 2, a 27 y. o. male. He complained of submental lymphadenopathy and lymph node resection was performed. Based on the immunohistological findings, NMZL was diagnosed. In the cytological assessment, both cases showed an increase of medium-sized and large atypical lymphocytes against the background of small lymphocytes. The atypical lymphocytes had irregular and indented nuclear contours and irregular chromatin pattern. Abundant pale cytoplasm was detected in the atypical lymphocytes on Giemsa staining. Zonal proliferation of CD20-, MUM-1-, and MIB-1- positive lymphoid cells were distributed in the enlarged paracortex. Conclusions : NMZL in patients less than 30 y. o. is rare. Since lymph follicles with germinal centers are preserved in NMZL, it is difficult to differentiate between NMZL and reactive lymphadenitis. It is necessary to detect nuclear atypia of infiltrating medium-sized and large lymphocytes in a high power field even in younger patients with lymphadenopathy.