Extraordinary Case ReportEpithelioid Fibrous Histiocytoma With Chondroblastoma-Like Features: A Report of a Rare Entity and Discussion of Related Diagnostic ChallengesWright, Glenda R. MBBCh*; Archibald, Curtis W. MD†,‡; Fontaine, Daniel MD§,¶; Dakin-Hache, Kelly MD, PhD*,§; Walsh, Noreen M. MD*,§,║ Author Information *Department of Pathology and Laboratory Medicine, Nova Scotia Health Authority (Central Zone), Halifax, NS, Canada; †Department of Ophthalmology, Nova Scotia Health Authority (Central Zone), Halifax, NS, Canada; Departments of ‡Ophthalmology and Visual Sciences, §Pathology, and; ‖Medicine, Dalhousie University, Halifax, NS, Canada; and ¶Department of Pathology and Laboratory Medicine, Nova Scotia Health Authority (Western Zone), Kentville, NS, Canada. Correspondence: Glenda R. Wright, MBBCh, Department of Pathology and Laboratory Medicine, QE II HSC, VG Site, Nova Scotia Health Authority (Central Zone), 5788 University Avenue, Halifax, NS, Canada B3H 1V8 (e-mail [email protected]). The authors declare no conflicts of interest. Patient consent statement: the authors state that the case report was conducted with the informed consent of the patient. The American Journal of Dermatopathology 44(1):p e11-e15, January 2022. | DOI: 10.1097/DAD.0000000000001986 Buy Metrics Abstract Epithelioid fibrous histiocytoma (EFH) is an uncommon benign skin lesion. It is distinct from FH by virtue of its recurrent anaplastic lymphoma kinase (ALK) gene rearrangements and immunohistochemical expression of ALK protein. It often poses a challenge in interpretation. Clinically, it is characterized by a flesh-colored papule/nodule on an extremity of a young to middle-aged individual. Microscopically, it is represented by a circumscribed dermal papule/nodule composed of sheets of plump epithelioid cells, forming whorled aggregates around numerous intralesional vessels. Immunohistochemistry, notably ALK positivity and relevant negative stains, serves to distinguish EFH from its morphological mimics. Rare examples of chondroblastoma-like EFH and EFH with osseous metaplasia are recorded in the literature. Our case is of a 58-year-old man who attended an oculoplastic surgeon because of an exophytic cutaneous nodule on the right upper eyelid. The lesion was excised. Microscopically, it displayed morphological and immunohistochemical features of EFH. Of interest, discrete foci of chondro-osseous change, including chondroblastoma-like pericellular calcification, osteoid formation, and osteoclast-like giant cells, were noted throughout the lesion. A diagnosis of EFH with chondroblastoma-like features was made. Of interest, the changes observed in this EFH serve to link the previously reported examples of pure chondroblastoma-like EFH and EFH with osseous metaplasia. This morphological variant of EFH adds to the existing diagnostic challenge presented by these lesions, particularly in the distinction from other calcifying tumors of the skin. Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.