T-Cell Prolymphocytic Leukemia Involving Extramedullary Sites

Abstract

T-cell prolymphocytic leukemia (T-PLL) can involve extramedullary sites, but the diagnosis is usually established by examination of blood and bone marrow. As a result, the histologic findings at extramedullary sites are poorly documented in the literature. We describe 19 extramedullary biopsy specimens from 14 patients with T-PLL. Skin (n = 10) was the most common site biopsied. T-PLL surrounded dermal blood vessels and appendages (n = 6), diffusely replaced dermis (n = 3), or formed a subcutaneous mass (n = 1). Other extramedullary sites included liver and lymph nodes (3 each) and spleen, lung, and cecum (1 each). In liver and lymph nodes, the neoplasm predominantly involved portal tracts and paracortex, respectively. Cytologically, the T-PLL cells were round (n = 16) or Sezary cell-like (n = 3). Nucleoli were observed in a subset of cells in 8 specimens and were prominent in 3 specimens. Immunostaining for T-cell leukemia-1 (TCL-1) was positive in specimens from 9 (64%) of 14 patients. We conclude that the prolymphocytoid features of T-PLL cells can be difficult to detect in routinely stained sections of extramedullary biopsy specimens. TCL-1 expression can aid in diagnosis at extramedullary sites.

Case study intrepretation–Houston: Case 4

“…Splenic infiltration leads to effacement of the normal splenic architecture with involvement of the red and white pulp. Skin involvement is characterized by perivascular and diffuse dermal infiltrates [10]. Lymph node involvement is usually diffuse with predilection for the paracortical area and the high endothelial venules [1].…”

Cytologic Features of Ascitic Fluid Complicated by Small Cell Variant T-cell Prolymphocytic Leukemia -A Case Report-

“…[1][2][3][4] In 25% of cases, leukemic prolymphocytes are small and do not have a visible nucleolus under light microscopy, and are designated small cell variant T-PLL. 5,6 We describe the cytomorphology of ascitic fluid T-cell prolymphocytic leukemia (T-PLL) is a rare, mature T-cell lymphoproliferative disorder with a post-thymic mature T-cell phenotype.…”

Mature T-Cell Leukemias Including T-Prolymphocytic Leukemia, Adult T-Cell Leukemia/Lymphoma, and Sézary Syndrome

“…Skin involvement and serous effusions, especially pleural, are encountered fairly often in this patient population. 15,16 Cases of T-PLL exhibit a morphologic spectrum in peripheral blood. Although nuclear chromatin condensation is typically present, characteristic of a mature cell disorder, the nuclear contours and prevalence of distinctive central nucleoli are quite variable ❚Image 2❚ and ❚Image 3❚.…”

“…14,16 However, TCL-1 expression is well documented in many other neoplasms, including B-cell leukemias and lymphomas and even nonneoplastic cells. 13,16,17 ❚Image 1❚ (Case 53) Peripheral blood smear in T-cell prolymphocytic leukemia with a WBC count >400,000/µL (>400.0 × 10 9 /L) showing striking mature lymphocytosis with variably sized lymphoid cells (Wright, ×75). In T-PLL, TCL-1 oncoprotein dysregulation is due to recurrent chromosomal rearrangements involving the TCL-1 locus at 14q32.1 and TCRαδ at 14q11 or, less commonly, the TCRβ locus at 7q35.…”