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

Lichen sclerosus: A C5B-9 mediated chronic microvascular injury syndrome potentially reflective of common adult comorbidities

Lichen sclerosus (LS) is a cutaneous disease of unknown etiology that often involves the vulva or foreskin but also can affect extragenital sites. Regardless of the anatomic site, the histomorphology and presumably pathogenesis are similar. Perhaps a clue to the pathophysiology of LS lies in its frequent association with morphea, specifically, when occurring in an extragenital context. In our experience a striking feature evident in established lichen sclerosis (LS) is one of superficial vascular drop out whereby residual vessels exhibited endothelial cell necrosis and microvascular basement membrane zone thickening, the latter reflective of antecedent episodes of microvascular injury. We sought to understand the pathophysiology that underlies the distinct vascular changes and in doing so, shed light on the pathogenesis of LS. We examined 44 cases of LS over a period of 2019 to 2021. We were able to obtain past medical histories in 34 of the 44 cases. Regarding pathological assessment, the predominant focus was on microvascular changes. We assessed the role of C5b-9 mediated vascular injury in the pathogenesis of the vasculopathy and enhanced type I interferon signaling in vessels given the morphologic semblance to the select interferonopathy syndromes, namely fibrosing dermatomyositis and Kohlmeier Degos disease. We examined the expression of CMV DNA and protein based on prior observations in an earlier study that isolated early protein expression in the microvasculature in the setting of LS and scleroderma. From a clinical perspective, the most striking association was an older age at the time of diagnosis (mean age of 62 years and median age of 61.5 years) and the presence of vascular comorbidities of diabetes, hypertension, and hyperlipidemia in almost 80% of cases. All cases showed significant microvascular changes in the superficial corium with the most frequent findings being those of significant basement membrane zone reduplication and vascular drop out. A number of cases showed prominent microvascular deposits of C5b-9 in the zone of hyalinizing fibrosis or subjacent to the discernible table of fibroplasia in the absence of enhanced type I interferon signaling. In no case were there viral cytopathic changes associated with CMV affecting the endothelium. The studies that encode CMV DNA or protein did not show a significant role for CMV reactivation in endothelium in the majority of the studied cases. It is concluded that the pathophysiology of LS includes a microvascular injury syndrome within the papillary dermis. The mechanism of endothelial cell injury is complement mediated at least in part and could reflect an adaptive immune response targeting endothelium indicative of classic complement pathway activation when coexisting with morphea or occurring in younger individuals. A non-immune based endothelial dysfunction and complement mediated injury unrelated to antibody driven classic complement pathway activation are more likely pathogenetically in the setting of certain diseases like diabetes mellitus and hypertension. Vascular drop out can be explained by the diminished endothelial progenitor pool needed to repopulate the damaged microvessels in certain settings like hypertension and diabetes.

Bullous lichen sclerosus-generalized morphea overlap syndrome improved by tofacitinib

We here report a case of a middle-aged man with an unusual case of bullous lichen sclerosus complicated with generalized morphea. He showed initial recurrent flaccid bullae, followed by ivory-white sclerotic plaques and extensive skin sclerosis, with additional walking disorder caused by knee-joint contracture, and ulcers on the lower extremities and back. The patient had no visceral involvement. After oral hydroxychloroquine and oral corticosteroids failed, the patient was given tofacitinib, which resolved his ulcers after 4 weeks and ameliorated his knee-joint contracture and skin sclerosis within 4 months. Owing to the occurrence of diffuse large B-cell lymphoma, he stopped using tofacitinib, and the ulcer and walking disorder reappeared. This is rare case of bullous lichen sclerosus-generalized morphea overlap syndrome. The patient recovered well after treatment with tofacitinib. His symptoms recurred after discontinuation of tofacitinib.

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

Background

Mycosis fungoides (MF) is a significant diagnostic challenge; it has various differential diagnosis especially at an early stage. Our aim was to describe mimics of MF clinically and histologically, and to define significant diagnostic criteria of the disease.

Methods

This was a retro-prospective cohort of 370 patients in whom the diagnosis of MF was suspected clinically.

Results

MF was histologically confirmed in 15.4% of cases and rejected in 84.5%. Other identified histologically diagnosis were eczema, psoriasis; nonspecific dermatitis, lichen, lupus; pseudolymphoma, parapsoriasis and toxidermia. 4 patients with palmoplantar MF were wrongly treated as eczema, and 10 patients with psoriasiform MF were initially treated as psoriasis. We also described the clinical, histological and immunohistochemistry diagnostic criteria for distinguishing MF from benign dermatosis.

Conclusions

Misdiagnosis of MF was a real problem for this study, because it shared common clinical and histological characteristics with other inflammatory diseases like eczema and psoriasis. Therefore, defining significant clinico-histological diagnosis criteria of MF would be of great help and would increase the accuracy of the diagnosis.

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

Mycosis fungoides is the most common primary cutaneous lymphoma; however, it remains a significant diagnostic challenge, in part because of the overlap with several inflammatory dermatoses. Despite advances in immunohistochemistry and molecular diagnostics, false-positive, false-negative, and indeterminate diagnoses are not uncommon. In most cases, the overall balance of morphologic, immunophenotypic, and genetic features must be considered carefully because there are few sensitive and specific clues to the diagnosis. Moreover, an appropriate clinical presentation is essential to the diagnosis and helps to favor or exclude inflammatory/reactive processes. Herein, we discuss 3 important inflammatory dermatoses that may closely simulate mycosis fungoides, and we review the use of ancillary studies in these challenging cases.