Aberrant epithelial membrane antigen expression in dermal cellular fibrous histiocytoma with central necrosis and epidermal ulceration: a potential mimicker of epithelioid sarcoma

Amianthoid-like fibers are hyalinized collagen mats which are characteristically found in intranodal palisaded myofibroblastoma. Only rarely they can be encountered in uterine classic-type leiomyomas. We herein report the first case of uterine atypical/bizarre cell leiomyoma which contained, as unusual and striking feature, numerous amianthoid-like collagen fibers. Diagnostic and histogenetic considerations are discussed. Pathologist should be aware of the possibility that the most diagnostically challenging variant of uterine leiomyoma, namely atypical/bizarre cell leiomyoma, may contain amianthoid-like fibers to avoid confusion with other tumors.