35th European Congress of Pathology , Dublin, İrlanda, 9 - 13 Eylül 2023, ss.184
Background & objectives
Apocrine carcinoma is rare cutaneous adnexal neoplasm with unclear histogenesis. Although
commonly seen in the axilla, it may also occur on scalp. This case report outlines
clinicopathological characteristics and diagnostic challenges of primary apocrine carcinoma
arising in nevus sebaseus background.
Methods
A 62-year-old male patient presented with a congenital right parietotemporal mass, which had
been progressively enlarging over the past decade and had developed ulceration within the
most recent year. Excision was performed with a prediagnosis of squamous cell carcinoma.
Results
Macroscopic examination revealed an irregularly circumscribed, polypoid mass with a central
ulcer. Microscopically, dermal tumoral infiltration with tubular structures of varying sizes were
observed. Some tubular structures showed central necrosis. Eosinophilic cytoplasmic
protrusions and a decapitation sign were present in some cells. Immunohistochemistry was
negative for ER, PR and D2-40, positive for AR and GATA3, focally positive for GCDFP15.
p63 antibody highlighted the myoepithelial cells in the in situ component. Nevus sebaceus was
observed surrounding the tumor.
Conclusion
Apocrine carcinomas have been reported to arise from benign lesions such as spiradenoma,
apocrine mixed tumor, and nevus sebaceus. Metastatic breast cancer should be considered
in the differential diagnosis, particularly for axillary lesions. The presence of nevus sebaceus
background and in situ components facilitated the diagnosis of a primary apocrine carcinoma
in our case. Meticilous microscopic and macroscopic examination should be performed when
necessary to identify the background lesion and demonstrate the in situ component.