Classical type and blastoid variant mantle cell lymphoma in the same lymph node: Histology and cytological findings from a touch imprint specimen.

Blastoid variant (BV) is one of the aggressive variants of mantle cell lymphoma (MCL). BV-MCL is defined by its blastic cytomorphology. Previous studies using sequential biopsies in cases with MCL have demonstrated that classical type MCL (C-MCL) often transforms or relapses as an aggressive variant, but a histopathological transition from C-MCL to an aggressive MCL variant in the same pathological specimen has been shown in only a limited number of the cases. We present a case of MCL in which a histological transition between C-MCL and BV-MCL was observed in the same lymph node. A 53-year-old man presented with a submandibular tumor. Touch imprint cytology revealed a monotonous proliferation of large blastic lymphoid cells. Histology revealed a transition between a large lymphoid cell component and small foci of small- to medium-sized cell component within the tumor. Both components were CD5(+), CD10(-), CD20(+), cyclin D1(+), and SOX11(+) on immunohistochemistry. Fluorescent in situ hybridization revealed the translocation of IgH/BCL1 locus. These findings led to a final diagnosis of BV-MCL with coexistent C-MCL. The present case suggests the existence of a pathogenetic pathway of MCL from C-MCL to BV-MCL. Because it is important to accurately identify BV-MCL for prognostication, appropriate ancillary diagnostic tools should be used in suspected cases. Diagn. Cytopathol. 2017;45:364-370. © 2016 Wiley Periodicals, Inc.