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T-Cell Prolymphocytic Leukemia Involving Extramedullary Sites

Jose R. Valbuena MD, Marco Herling MD, Joan H. Admirand MD, Anthony Padula MD, Dan Jones MD, PhD, L. Jeffrey Medeiros MD
DOI: http://dx.doi.org/10.1309/93P42RNG5XBG3KBE 456-464 First published online: 1 March 2005


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 Sézary 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.

Key Words:
  • T-cell prolymphocytic leukemia
  • Extramedullary sites
  • TCL-1