| 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. © 2020 Wolters Kluwer Health, Inc. All rights reserved. |
