Mycosis fungoides with spongiosis: A potential diagnostic pitfall

Abstract

Background Mycosis fungoides (MF) is characterized by epidermotropic atypical lymphocytes in the absence of spongiosis. However, we describe an unusual presentation of MF with spongiosis, mimicking benign inflammatory dermatoses and highlight the importance of pathologic interpretation for diagnostic confirmation. Methods A cross‐sectional study of consecutive patients diagnosed with MF with spongiosis was conducted. The clinical, histopathologic, immunophenotypic, and molecular genetic features of cases were reviewed. Results We identified nine cases of MF (age range 34‐82 years; mean 75 years), with an initial diagnosis of dermatitis (6/9), psoriasis (4/9), or other inflammatory dermatoses (2/9). Pruritus, pain, and blisters were common clinical manifestations. The most common areas of involvement were the extremities (8/9). Epidermotropism with spongiosis was a central histopathological feature in all cases. Conclusion These cases highlight prominent spongiosis in MF and overlap with common benign inflammatory dermatoses. We present these cases to show the diagnostic pitfalls associated with spongiotic presentations of MF. Dermatitis, psoriasis, and other inflammatory skin conditions not responsive to standard therapy warrant further work‐up including biopsy to rule out MF. Multiple skin biopsies and review by a dermatopathologist with expertise in the diagnosis of cutaneous lymphoma is highly recommended.

Characteristics and outcomes of 727 patients with mycosis fungoides and Sézary syndrome from a Brazilian cohort

“…42 Absence of spongiosis is also important in MF/SS diagnosis, 43,44 but it was observed in more than half of the patients, probably due to skin barrier alteration, increasing eczematous reactions. 45 The predominant phenotype was CD4 (62.9%), with partial CD7 loss in 74.2% of MF and 69.2% of SS patients. Loss of CD2 and CD5 were less frequent.…”

Application of the current diagnostic algorithm for early mycosis fungoides to a single center cohort: Identification of challenges and suggestions for modification

“…Histopathologic diagnosis of mycosis fungoides (MF) in early stages is challenging 1,2 . Because of the significant overlap of pathologic features in early‐stage MF and various inflammatory dermatoses, multiple biopsy specimens taken over years are often required before a diagnosis of MF is established.…”

Next-Generation Sequencing Technologies for Early-Stage Cutaneous T-Cell Lymphoma

“…This microabscess is considered the histopathological hallmark of disease, but it is only observed in <20% of early MF cases (6). These microabscesses are also usually recognized as epidermotropic atypical lymphocyte infiltration without spongiosis, although spongiotic variants of MF have been reported (7, 8). Morphologic characterization of early-stage MF might show non-specific findings (9), because skin lesions are infiltrated by large numbers of non-malignant memory T cells, often making it impossible to distinguish malignant T cell clones from activated benign infiltrating T cells based on histopathology (6).…”