Original ArticlesSpindle-cell (Sarcomatoid) Variant of Cutaneous Anaplastic Large-cell Lymphoma (C-ALCL) An Unusual Mimicker of Cutaneous Malignant Mesenchymal Tumors—A Series of 11 CasesGru, Alejandro A. MD*; Bhagat, Govind MD†; Subtil, Antonio MD‡; Raghavan, Shyam S. MD*; Pulitzer, Melissa MD§; Chung, Catherine MD∥; Sangueza, Martin MD¶; Plaza, Jose A. MD∥Author Information *Department of Pathology & Dermatology, University of Virginia, Charlottesville, VA †Department of Pathology and Cell Biology, Columbia University Irving Medical Center §Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York City, NY ‡Department of Pathology, Royal-Jubilee Hospital, Victoria, BC, Canada ∥Department of Pathology & Dermatology, The Ohio State University Wexner Medical Center, Columbus, OH ¶Department of Pathology, Hospital Obrero, La Paz, Bolivia Conflicts of Interest and Source of Funding: The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article. Correspondence: Alejandro A. Gru, MD, Department of Pathology & Dermatology, University of Virginia, Charlottesville, VA 22910 (e-mail: [email protected]). The American Journal of Surgical Pathology: June 2021 - Volume 45 - Issue 6 - p 796-802 doi: 10.1097/PAS.0000000000001623 Buy Metrics Abstract Cutaneous anaplastic large-cell lymphoma (C-ALCL) represents one of the entities within the group of CD30-positive lymphoproliferative disorders of the skin. Most cases are ALK-negative, though isolated cases of ALK-positive C-ALCL have also been reported. By definition, the diagnosis of C-ALCL requires the expression of CD30 in >75% of the cells. Histopathologically, C-ALCL shows a dermal-based nodular and circumscribed proliferation of large pleomorphic cells with vesicular nuclei, prominent nucleoli, and eosinophilic cytoplasm, including hallmark cells. Since 1990, isolated case reports of a so-called “sarcomatoid” variant have been published in the literature. Herein, we present a series of 11 cases of spindle (sarcomatoid) C-ALCL, with comprehensive histopathologic, immunophenotypic, and molecular data. Spindle C-ALCL represents a potential mimicker of malignant mesenchymal or hematopoietic tumors in the skin and should always be considered in the differential diagnosis when assessing cutaneous pleomorphic spindle cell neoplasms. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.