Solitary CD8-Positive Primary Cutaneous Peripheral T-Cell Lymphoma: A Question of Classification

Abstract

Acral CD8(+) lymphoma is a provisional entity in the latest edition of the WHO Lymphoma Classification and is associated with a highly specific dot-like pattern of immunohistochemical expression of CD68. We report a case of an ulcerated solitary cutaneous lesion arising on the forehead of an adult man, which had a CD8(+) cytotoxic phenotype and areas of dot-like CD68 positivity, but with a number of features that significantly detracted from the classically described acral CD8(+) lymphoma. The nosological status of the lesion is discussed with respect to a preferred diagnosis of peripheral T-cell lymphoma, not otherwise specified.

Primary Cutaneous Peripheral T-Cell Lymphoma NOS: Diagnostic Criteria and Challenges

“…A recent report of a solitary CD8 + tumor arising on the forehead of an adult, which followed an indolent course, was similarly labeled as peripheral TCL NOS because of several features that differed from the classic examples of PCAL, namely ulceration, conspicuous epidermotropism, and a polymorphic infiltrate with inconspicuous CD68 expression. 23 There are reports and case series of solitary examples of CD8 + PTCL NOS. [23][24][25][26][27][28][29] Most recently, Kempf et al 29 compared a large series of PCAL with 11 examples of PTCL NOS, of which 8 were solitary.…”

“…23 There are reports and case series of solitary examples of CD8 + PTCL NOS. [23][24][25][26][27][28][29] Most recently, Kempf et al 29 compared a large series of PCAL with 11 examples of PTCL NOS, of which 8 were solitary. These tumors often had rapid clinical development, included examples with medium-large neoplastic cells and moderate-severe cytological pleomorphism, with epidermotropism, albeit sometimes focal; granzyme B and/or perforin were expressed, and the proliferative fraction manifested by mitotic counts or Ki67 index, high (.50%).…”

“…Four additional cases of PCAL investigated had low or absent p16 by immunohistochemistry, but none of these had a fluorescence in situ hybridisation-detected deletion. 22 The atypical features, including very high proliferation rate and gene deletion, led to a preferred diagnosis of PTCL NOS. A recent report of a solitary CD8 + tumor arising on the forehead of an adult, which followed an indolent course, was similarly labeled as peripheral TCL NOS because of several features that differed from the classic examples of PCAL, namely ulceration, conspicuous epidermotropism, and a polymorphic infiltrate with inconspicuous CD68 expression.…”