Dermal Pleomorphic Sarcoma of the Scalp: A Case Report

Pleomorphic dermal sarcoma (PDS) is a rare cutaneous malignancy that predominantly affects elderly individuals and typically arises in chronically sun-exposed areas, particularly the scalp and face.It is distinguished from atypical fibroxanthoma by the presence of high-risk histopathological features, including subcutaneous invasion, tumor necrosis, and perineural or lymphovascular invasion.We report the case of a 90-year-old man admitted to Mohammed VI University Hospital in Oujda, Morocco, in November 2025, for a progressively enlarging occipital scalp mass that had become painful and ulcerated.Clinical examination revealed a large, exophytic, ulcerated tumor measuring approximately 20 cm.Histopathological examination of the excision specimen demonstrated a markedly pleomorphic spindle and epithelioid cell proliferation with atypical mitotic figures, tumor necrosis, and perineural invasion.Immunohistochemistry revealed diffuse, strong CD10 expression and heterogeneous CD68 positivity, while epithelial, melanocytic, and endothelial markers were negative, supporting the diagnosis of PDS after exclusion of relevant differential diagnoses.This case illustrates the importance of recognizing the characteristic histopathological features of PDS and integrating immunohistochemistry into the diagnostic workup.It also highlights the diagnostic challenges posed by a giant scalp tumor in an elderly patient and the need for appropriate management and clinical follow-up, given the potential for local recurrence and metastasis.