Extragenital lichen sclerosus et atrophicus mimicking cutaneous T‐cell lymphoma: report of a case

Abstract

Early lesions of lichen sclerosus et atrophicus (LSA) may present as a mild lichenoid tissue reaction, occasionally together with basilar epidermotropism, mimicking early cutaneous T‐cell lymphoma, mycosis fungoides (MF) variant. We report a case of extragenital LSA in which both histological patterns were present in the same clinically homogenous and stable lesion. A 27‐year‐old man presented with a history of white atrophic plaques on the trunk. A biopsy of an abdominal lesion revealed epidermal thinning, a superficial perivascular lymphoid cell infiltrate with focal epidermotropism, mild nuclear atypia and perinuclear halos. Immunophenotyping showed decreased CD5 and CD7, with a slight predominance of CD8‐positive T‐lymphocytes. All these changes were suggestive of MF. However, a repeat biopsy 3 months later from the same stable plaque revealed features diagnostic of LSA. LSA mimicking early MF histologically has been reported in genital skin. Conversely, MF may clinically and histopathologically resemble LSA. With gene rearrangement studies, clonal proliferation may not be detected in early MF but has been reported to occur in LSA. Awareness of the histopathologic spectrum of LSA within a stable plaque is important to avoid a potential diagnostic pitfall, and should prompt a repeat biopsy. Suchak R, Verdolini R, Robson A and Stefanato CM. Extragenital lichen sclerosus et atrophicus mimicking cutaneous T‐cell lymphoma: report of a case.

Selected Inflammatory Imitators of Mycosis Fungoides: Histologic Features and Utility of Ancillary Studies

“…Lymphocytes may migrate into the basilar epidermis with limited, associated spongiosis, resembling MF. 19,[25][26][27][28] In addition, the papillary dermis may display coarse or wiry collagen bundles. 26 Developed lesions of LSA show hyperkeratosis, follicular plugging, and epidermal atrophy.…”

“…4,13 In cases in which integration of clinical history, histopathology, and ancillary techniques fails to discern a definitive diagnosis, it may be preferable to defer the diagnosis until a subsequent biopsy is obtained. 13,19,20 Despite all the challenges in diagnosing MF and its mimics, accurate classification is necessary for patient staging, prognosis, and therapy. Herein, we review selected inflammatory dermatoses that may closely simulate MF, focusing on distinguishing clinicopathologic features and the use of ancillary studies.…”

“…3,4,15,[52][53][54] Importantly, reactive processes may show loss of T-cell markers, most commonly CD7 and CD5. 19,44,51,53,[55][56][57][58] However, the loss of those markers in inflammatory conditions is often less extensive than it is in MF. 4,59 In addition, many inflammatory dermatoses show a near-equal mixture of CD4 þ and CD8 þ T cells or only a mild predominance, 19,40,44,54,55 although this generalization is far from universal.…”

“…19,44,51,53,[55][56][57][58] However, the loss of those markers in inflammatory conditions is often less extensive than it is in MF. 4,59 In addition, many inflammatory dermatoses show a near-equal mixture of CD4 þ and CD8 þ T cells or only a mild predominance, 19,40,44,54,55 although this generalization is far from universal. 51 T-cell receptor gene rearrangement studies may also substantiate a diagnosis of MF but are neither entirely sensitive nor specific.…”

Interstitial Mycosis Fungoides With Lichen Sclerosus–Like Clinical and Histopathological Features

“…LS, both in its genital and extragenital forms, can histopathologically mimic MF, creating a potential diagnostic pitfall. 3,[8][9][10][11][12] However, isolated cases of overlap between MF and LS, 13 and MF clinically presenting with lesions resembling LS, 14 have also been described (Table 1), further complicating the interplay between these 2 entities.…”