Longtime undetected microcystic adnexal carcinoma of the scalp: considerations and implications

Background. Microcystic adnexal carcinomas (MACs) are slow-growing and often asymptomatic, malignant skin tumours that usually develop on the facial skin and may reach considerable size. We present a case of MAC arising on the hair-bearing scalp and discuss our experiences and considerations. To our knowledge, it is the first report of a MAC developing in this area. Case report. A 58-year-old female was admitted with a histopathologically secured diagnosis of MAC of the temporal and occipital regions that had expanded to 10 × 12 cm. Magnetic resonance imaging revealed an infiltration of the skin and the subcutaneous adipose tissue. No lymphatic or haematogenic metastases were detected. Therapy consisted of resecting the tumour and reconstructing the area by applying an anterolateral thigh (ALT) flap. Histopathological evaluation revealed clear, 1 cm margins and a tumour-free periosteum. One-year postoperative follow-ups showed no evidence of recurrence, while the outcome was aesthetically pleasing. Conclusion. When screening for skin cancer, careful attention must be paid to the scalp. Resection of MAC with clear margins is mandatory to minimize the risk of recurrence. In this case, applying an ALT perforator flap to a large defect of the hair-bearing scalp led to a very satisfying result; it should be considered in comparable cases. Keywords: Skin cancer, Microcystic adnexal carcinoma, Anterolateral thigh flap, Magnetic resonance imaging, Skin cancer screening