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.