A Case Report of Eccrine Porocarcinoma on the Scalp

Abstract

Eccrine porocarcinoma (EPC) is an exceptionally rare malignant adnexal neoplasm originating from the intraepidermal eccrine sweat duct, constituting < 0.01% of all cutaneous tumors. Its non-specific clinical presentation frequently results in misdiagnosis, and histopathological evaluation remains the diagnostic cornerstone. A 72-year-old female, who presented with a progressively enlarging, ulcerated mass on the left temporal region of the scalp. The lesion was surgically excised. Gross examination revealed a gray-brown nodular ulcerated mass with attached hair, measuring 3.5 × 2.5 × 2 cm, with solid gray-white areas and focal hemorrhage on the cut section. Microscopy demonstrated an intradermal malignant neoplasm maintaining continuity with the overlying epidermis, composed of nests, strands, and lobules of markedly pleomorphic poroid cells. The cells exhibited high nuclear-to-cytoplasmic ratios, hyperchromatic irregular nuclei, prominent nucleoli, focal clear cell change, nuclear grooving, increased mitotic activity (1–2/high-power field) including atypical mitoses, and a surrounding lymphoplasmacytic stromal infiltrate. These findings were diagnostic of EPC. Although the lower extremity is the most common site, EPC should be considered in the differential diagnosis of chronic ulcerated scalp lesions in the elderly. Complete surgical excision with tumor-free margins is essential to mitigate the risk of local recurrence and metastasis.