Relationship between hairy cell leukemia variant and splenic lymphoma with villous lymphocytes: Presentation of a new concept

Abstract

An unusual case of low-grade B-cell lymphoproliferative disorder with peripheral lymphocytosis and splenomegaly followed for 4 1/2 years is reported. During this period, the phenotype of the tumor cells in the blood changed from that of hairy cell leukemia (HCL)/chronic lymphocyte leukemia (CLL) to HCL/prolymphocytic leukemia (PLL), to PLL. The lymphoid population in the blood showed a mixture of hairy cells, villous lymphocytes, small lymphocytes, and prolymphocytes, corresponding to the phenotypes at various stages. Although relatively specific markers for CLL, HCL, and PLL, such as CD5, CD11c, CD22, CD25, and FMC-7, were positive at various stages, all these markers have also been demonstrated in a large study series of splenic lymphoma with villous lymphocytes (SLVL). In addition, the histologic pattern of the bone marrow biopsy and splenectomy specimen were not typical for HCL. This case can therefore be classified either as HCL variant or as SLVL. As SLVL assumes various cytologic and histologic patterns, which overlap with different lymphoproliferative disorders, especially HCL variants, this entity appears to represent a heterogeneous group of lymphomas/leukemias that may evolve into each other. The absence of activation of c-myc and bc1-2 oncogenes as well as mutation of p53 tumor suppressor gene, together with the presence of only one single rearranged band for both heavy chain and kappa light chain genes in our case suggest that these morphologically different lymphoid tumors may belong to the same family.

Splenic small B‐cell lymphoma with predominant red pulp involvement: a diffuse variant of splenic marginal zone lymphoma?

“…Cases similar to the ones presented here have been presented in the past in different terms, emphasizing some of their features, such as lymphocytic lymphoma simulating hairy cell leukaemia, splenic B‐cell lymphoma with villous lymphocytes, lymphomas with a massive red pulp infiltration, monocytoid B‐cell lymphoma in the spleen, and atypical hairy‐cell leukaemia, or B‐lymphocytic lymphoma of possible splenic marginal zone origin 18 –24 . They also could overlap with some of those described by Hammer et al 15 .…”

Splenic marginal zone lymphoma proposals for a revision of diagnostic, staging and therapeutic criteria

“…The term HCL-v describes cases of B-chronic lymphoproliferative disorders that look like classic HCL but shows variant cytological features (that is leukocytosis, presence of monocytes, cells with prominent nucleoli, cells with blastic or convoluted nuclei and/or absence of hairy silhouette contours), variant immunophenotype (that is absence of CD25, CD123--anti-interleukin-3 receptor, annexin-1 or TRAP), and resistance to conventional HCL therapy. [61][62][63] Cases of HCL-v with spleen, BM or peripheral blood features overlapping those of SMZL have been reported, 64,65 and more in particular with the entity denominated as splenic diffuse red pulp small B-cell lymphoma. Still in HCL-v, the cells are often CD103 þ (two-thirds of the cases), while they are negative with CD25 and, usually CD24 negative.…”

Hairy cell leukemia: biology, clinical diagnosis, unusual manifestations and associated disorders

“…A variant form of the HC has been described which is quite similar to the prolymphocytes seen in B-prolymphocytic leukemia (B-PLL) (42)(43)(44)(45)(46). This variant HC has a more central round nucleus with a prominent nucleolus and coarse chromatin pattern (Fig 3).…”