Aggressive Primary Cutaneous Apocrine Carcinoma of the Scalp: A Clinical Case Report

Primary cutaneous apocrine carcinoma (PCAC) is a rare malignancy originating from the apocrine glands of the skin. It is predominantly found in regions rich in apocrine glands, such as the axilla and anogenital area. Scalp involvement is rare, and the disease's aggressive behavior further complicates its management. A 78-year-old male with a history of primary cutaneous apocrine carcinoma (PCAC) of the neck, previously managed with craniotomy, radiation, and chemotherapy, presented five years later with recurrence and bone metastasis. Six years after the initial diagnosis, he developed enlarging masses in the neck, necessitating extensive surgical resection. Histopathology confirmed primary cutaneous cribriform apocrine carcinoma with positive markers for CK7, GCDFP-15, EMA, and androgen receptors. Further molecular analysis performed on a fine-needle aspiration biopsy revealed pathogenic and likely pathogenic alterations, including HRAS G13R and FBXW7 Y545C. The patient underwent successful resection of the neck apocrine carcinoma by neurosurgeons, followed by soft tissue reconstruction by plastic surgeons. This case highlights the importance and challenges of diagnosing and managing a scalp PCAC with recurrence and bone metastasis and the need for more aggressive follow-up and treatment strategies in similar cases.