Usefulness (or Lack, Thereof) of Immunophenotyping in Atypical Cutaneous T-Cell Infiltrates

Abstract

Our purpose was to evaluate the interobserver concordance for the diagnoses of mycosis fungoides (MF), atypical dermatoses (AD), and benign dermatoses (BD) and the impact of T-cell immunophenotyping on the diagnoses MF, AD, and BD. Specimens of MF (n = 57), AD (n = 27), BD and normal skin (n = 54) were reviewed by 2 hematopathologists and 1 dermatopathologist to establish diagnostic interobserver concordance by routine morphologic examination. Immunophenotyping was performed to evaluate expression of CD2, CD3, CD4, CD5, CD7, CD8, CD20, CD30, and MIB-1. The interobserver concordance was fair to moderate compared with the original diagnosis. Partial deletion of CD2 alone was associated significantly with MF. Epidermal deletions of 2 or 3 T-cell antigens or 2 T-cell antigens not including CD7 were associated significantly with MF. An elevated CD4/CD8 ratio correlated with MF. Morphologic features were most diagnostic of MF. Immunophenotyping generally resulted in downgrading of the reaction pattern but was helpful in distinguishing MF from benign dermatoses.

TCR-γ Expression in Primary Cutaneous T-cell Lymphomas

“…Neoplastic cells usually express CD3, CD2, CD4, TCR-BF1, and CD5 and frequently lose the expression of CD7. 44,45 Cases expressing CD8 or that are CD4/CD8 double-negative have been reported, and do not seem to behave differently from CD4 + cases. [46][47][48][49][50][51][52][53] Expression of cytotoxic markers by neoplastic cells in MF increases with progression from plaque stage to tumoral stage disease.…”

Expression of proliferation markers and cell cycle regulators in T cell lymphoproliferative skin disorders

“…It has previously been shown that an increased CD4/CD8 ratio on immunohistology is associated with more advanced stages of MF. However, an appropriate cut-off value (e.g., >2) is controversial and seems to depend, in part, on the personal experience of the pathologist signing out the case [28]. The most widely used conventional proliferation markers include Ki-67 and PCNA.…”

A Review of Survival in Mycosis Fungoides

“…Yet, MF is not common, and its histologic definition remains both elusive and controversial. [1][2][3][4][5] Many investigators have thoroughly studied the histologic features of MF, [3][4][5][6][7][8][9][10][11][12][13][14][15][16] finally achieving a consensus of sorts that emphasizes the importance of the following: MF cells' cytology (modestly enlarged lymphocytes with dark convoluted nuclei and, for the most part, a high nuclear-to-cytoplasmic ratio), the presence of these cells in the epidermis (in basilar epidermal rows, scattered singly, or in Pautrier clusters), the clear halos that often surround these cells, their presence in the papillary dermis (where they are often appear interstitially among collagen fibers), and the limited changes typical for spongiotic or other dermatoses. 1,[3][4][5]15,[17][18][19][20] Despite this consensus, benign nonlymphomatous mimics of MF confound the diagnosis.…”