Histopathologic Features of Early (Patch) Lesions of Mycosis Fungoides

Abstract

The histologic diagnosis of early mycosis fungoides (MF) is one of the most vexing problems in dermatopathology. We reviewed the histopathologic features of 745 biopsy specimens from 427 patients (male:female = 277:150; median age, 52 years; range, 3-95 years) with early (patch) lesions of MF collected from the lymphoma database of the Department of Dermatology of the Medical University of Graz (Austria). In all patients, the diagnosis was established by clinicopathologic correlation. The most common histopathologic pattern consisted of a band-like or patchy lichenoid infiltrate admixed with coarse bundles of collagen in the superficial dermis. Epidermotropism of lymphocytes was observed in most cases in one or more forms (single lymphocyte epidermotropism, 22%; basilar lymphocytes, 23%; Pautrier's microabscesses, 19%; "haloed" lymphocytes, 40%; disproportionate exocytosis, 17%; pagetoid epidermotropism, 3%). In 4% of cases, epidermotropism was completely missing. Atypical lymphocytes were present only in 9% of cases. Features of interface dermatitis were observed in 59% of cases. Other unusual findings were the presence of necrotic keratinocytes (23%), melanophages (8%), and extravasated erythrocytes (4%). In 28 patients, two or more biopsies taken on the same day at different body sites showed different histopathologic aspects, underlying the protean features of MF even in a single patient at a given time. Our study expands previous observations on histopathologic features of early lesions of MF. Although sometimes the histopathologic features are not diagnostic, they should be considered consistent with MF and do not rule out the diagnosis.

Defining the mimics and clinico-histological diagnosis criteria for mycosis fungoides to minimize misdiagnosis

“…Pautrier microabscess is considered more specific for MF but is only seen in 4% to 37% of lesions in an early stage (Burg et al, 2005, Massone et al, 2005, Naraghi et al, 2003, Santucci et al, 2000, Shapiro and Pinto, 1994) and in 29.8% in our study. In some cases, atypical lymphocytes in MF may be associated with spongiosis but the degree is usually far less than would be expected for the number of lymphocytes in the epidermis, a feature that is sometimes called disproportionate epidermotropism (Massone et al, 2005, Pimpinelli et al, 2005, Sanchez and Ackerman, 1979).…”

“…The histopathologic features of MF in an early stage vary from person to person, over time, and even between multiple sites in a single patient (Ferrara et al, 2008, Massone et al, 2005). In addition, topical steroid therapy and systemic immunosuppressant medications may influence the findings up to 2 to 4 weeks (Nickoloff, 1988, Pimpinelli et al, 2005).…”

“…However, none of these features are entirely specific for MF. Even though the pattern may vary, epidermotropism is considered a hallmark of MF and has been reported in up to 96% of patients with MF in an early stage (Massone et al, 2005). In our study, epidermotropism was present in 89.4% of patients.…”

“…In some cases, atypical lymphocytes in MF may be associated with spongiosis but the degree is usually far less than would be expected for the number of lymphocytes in the epidermis, a feature that is sometimes called disproportionate epidermotropism (Massone et al, 2005, Pimpinelli et al, 2005, Sanchez and Ackerman, 1979). …”

“…MF affects most commonly middle-aged and elderly adults of all races Hwang et al, 2008, Scarisbrick, 2006) who usually present with persistent and/or slowly progressive skin lesions of varying sizes and shapes (Fatemi Naeini et al, 2015, Jang et al, 2012). The natural history of MF is characterized by an indolent progression through four disease stages: patch, plaque, tumor, and visceral involvement (Kazakov et al, 2004, Kim-James and Heffernan, 2001, Zinzani et al, 2008) Less than one-third of patients with MF develop advanced disease that involves lymph nodes, blood, and visceral organs (Howard and Smoller, 2000, Hwang et al, 2008: Kim et al, 2003, Massone et al, 2005, Paulli and Berti, 2004, Pope et al, 2010, Song et al, 2013). …”