Reflectance confocal microscopy findings in a case of molluscum contagiosum

Abstract

We present the case of a 74-year-old man who presented for his annual skin check and had a new suspicious lesion on his left cheek consistent with a pink-white papule showing a mixed vascular pattern (Fig 1). The patient had a medical history of 2 previously treated basal cell carcinomas on his face. The lesion was clinically suspicious for a new-onset basal cell carcinoma. The patient was referred for reflectance confocal microscopy to confirm the nature of the lesion. Nonpolarized contact dermatoscopy revealed a pink and yellow to white, relatively well-demarcated papule with a central clod-like, very faintly polylobular, white-to-yellow, amorphous structure (Fig 2). This central area corresponded to the round-to-oval lobules seen on confocal microscopy and to the central lobulated endophytic hyperplasia seen on histopathology (Fig 3).Fig 3Molluscum contagiosum - reflectance confocal microscopy, zoomed in. Higher magnification into the central lobular area revealed hyper-refractive cell outlines with hyporefractive central areas within these lobules. Note the slightly grainy cytoplasm of these cells, corresponding to Henderson-Paterson(molluscum) bodies. It was necessary to alter the brightness and contrast in the reporting software (Vivanet) to better visualize the individual cell outlines (Vivascope 1500, Caliber I.D.; Imaging & Diagnostics, Inc).View Large Image Figure ViewerDownload Hi-res image Download (PPT) The vascular pattern was mixed, with a few focal crown-like vessels and multiple prominent circumferentially arranged radial blood vessels, some exhibiting a branching pattern. Shiny white structures were not readily appreciated. The dermatoscopic differentials by a panel of experts at consensus included a possible sebaceous neoplasm given the polylobular appearance and focal crown vessels or a basal cell carcinoma with atypical dermatoscopic features given the radial blood vessels with some arborizing features. Confocal microscopy (Vivascope 1500, Caliber I.D.; Imaging & Diagnostics, Inc) revealed a well-circumscribed lesion with central, relatively uniform, hyporefractive, round-to-oval lobules forming a central polylobular structure (Fig 4). This central polylobular area corresponded to the central yellow-to-white clod seen on dermatoscopy. Higher power confocal microscopy views of the individual lobules revealed multiple slightly hyperrefractive cells within each lobule. The individual cells with large, round, hyperreflective intracytoplasmic inclusions corresponded to the Henderson-Paterson bodies observed on histology. Because of the fact that the authors were unfamiliar with the confocal findings, biopsy was performed to rule out possible sebaceous neoplasm or an atypical basal cell carcinoma. The hyporefractive lobules in the central section of the lesion exhibited the typical histopathology of molluscum contagiosum (MC) with a central area displaying lobules and endophytic hyperplasia (Fig 5). At the microscopic single-cell level, hyper-refractive round-to-oval cells within each lobule observed at reflectance confocal microscopy corresponded histologically to the individual enlarged keratinocytes containing intracytoplasmic eosinophilic, hyalinized viral inclusions that displaced the nucleus peripherally (Henderson-Paterson bodies), a typical finding of MC. MC usually has a typical clinical and dermatoscopic appearance on which most diagnoses are based. Some lesions, however, may have an unusual morphology, making clinical or dermatoscopic evaluation challenging or equivocal. This may sometimes lead to suspicion for neoplasm, necessitating biopsy and histopathologic evaluation. In this case, an evaluation of the findings and currently available literature appears to suggest that the reflectance confocal microscopy findings of MC are very characteristic and reproducible, even when MC lesions appear atypical clinically or on dermatoscopy.1Broggi G. Verzì A.E. Micali G. Caltabiano R. Lacarrubba F. Horizontal histopathology correlates with in vivo reflectance confocal microscopy features of molluscum contagiosum: a case series.J Cutan Pathol. 2021; 48: 1430-1431https://doi.org/10.1111/cup.14106Crossref PubMed Scopus (2) Google Scholar,2Cinotti E. Perrot J.L. Labeille B. Cambazard F. Reflectance confocal microscopy for cutaneous infections and infestations.J Eur Acad Dermatol Venereol. 2016; 30: 754-763https://doi.org/10.1111/jdv.13254Crossref PubMed Scopus (38) Google Scholar Awareness of the confocal findings of MC among new confocal microscopists could avoid unnecessary biopsies for these benign lesions. None disclosed.