Cyclin D1 Negative Mantle Cell Lymphoma
From the Friday Unknowns
The patient presented in 2020 with diffuse lymphadenopathy and massive splenomegaly. Flow cytometry immunophenotyping of peripheral blood showed a CD5-positive lambda-positive B-cell population. FISH on this blood specimen showed ATM deletion and loss of chromosome 13.
The lymph node biopsy specimen shows extensive replacement by lymphoma. The neoplasm is mostly diffuse with minor nodular areas. The neoplastic cells have mostly classic cytologic features but there is some pleomorphism.
Flow cytometry immunophenotypic analysis performed on this lymphoma node showed a B-cell population positive for lambda, CD5, CD11c (partial), CD19, CD20, CD22, CD23, CD25 (dim), CD38, CD52 (dim), CD79b (dim) and FMC7, and negative for CD10, CD103 and CD200.
The lymphoma cells are positive for CD5 (weak), CD20, CD43, BCL-2 and SOX-11, and are negative for CD3, CD10, CD21, CD23, CD138, BCL-6, cyclin D1, p53 and kappa and lambda. The antibodies specific for CD21 and CD23 highlight follicular dendritic cells in nodular areas. The antibody specific for KI-67 shows a proliferation rate of 30–40%.