Atypical Histiocytic Lesion Preceding a Peripheral T-Cell Lymphoma Involving the Skin Exhibiting the Same Molecular Alterations

Abstract: Peripheral T-cell lymphoma (PTCL), not otherwise specified (NOS) is a diagnosis of exclusion, showing extreme cytological and phenotypic heterogeneity. Skin involvement of PTCL may be primary or secondary. Diagnosis of histiocytosis may be difficult, requiring clinical–pathological correlation. We describe a laryngeal atypical histiocytic lesion (AHL) and a nasal PTCL, NOS with cutaneous involvement in the same patient presenting with peculiar histopathologic and immunophenotypic features. The laryngeal neoplasm showed morphological and immunophenotypic evidence of histiocytic differentiation and does not fit any other category of the WHO classification nor the revised classification of histiocytosis. The nasal and cutaneous lesions presented features close to natural killer/T-cell lymphoma and gamma–delta T-cell lymphoma but did not meet accurately the WHO criteria. A somatic activating Q61K mutation was found on exon 3 of the NRAS gene in both AHL and PTCL, NOS. The mutation on NRAS gene in both AHL and PTCL, NOS may suggest a common origin from a precursor cell. Correspondence: Salma Machan, MD, Fundación Jiménez Díaz, Servicio de Dermatología, Av. De los Reyes Católicos, 2, Madrid 28040, Spain (e-mail: smachan@fjd.es). Supported by grants from the Instituto de Salud Carlos III, from Ministerio de Economía, Industria y Competitividad [RTICC RD06/0020/0107, RD12/0036/0060, PI12/1682, PT13/0010/0007, PI16/01294, SAF2013-47416-R, CIBERONC-ISCIII PIE15/0081, ISCIII-MINECO AES-FEDER (Plan Estatal I+D+I 2013-2016): PI14/00221 and PIE14/0064], and the Asociación Española Contra el Cáncer, Spain. The authors declare no conflicts of interest. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (https://ift.tt/2hxkbZ3). Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.

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