A malignant spiradenoma of the forehead: a case report and literature review

Spiroadenomas, arising from sweat glands, are rare benign skin tumors primarily found as solitary nodules on the head, neck, and trunk. The malignant subtype, Spiradenocarcinoma (MSA), originating from benign spiradenomas, is extremely rare and occurs mainly in individuals over 50. MSA exhibits aggressiveness with higher metastasis rates and lower survival rates. Surgical excision is the standard management, supported by imaging modalities like MRI, CT-scan, and ultrasound. We present a 69-year-old female with a medical history of diabetes, hypertension, and dyslipidemia who presented in 2014 with multiple swellings on the forehead and left arm. Initial excisions revealed capillary hemangioma lesions. Subsequent visits involved the excision of further facial and body lesions, with some identified as intradermal nevi. In 2022, she presented to plastic surgery clinic with forehead swelling. The biopsy showed MSA lesion with involved margins. Thus, subsequent re-excision was carried out. One year later, she came with recurrent forehead swelling. Excision and direct closure of the lesion showed involvement of part of the subcutaneous tissue (fat globule) showing residual/recurrent MSA that is very close to nerve trunks. Malignant Spiradenomas (MSAs) usually arise from benign spiradenomas. Therefore, consideration is given to preemptive removal of these tumors due to their potential evolution. The primary treatment approach involves surgery, with a focus on wide local excision and a minimum margin of 1 cm to diminish the risk of metastasis. Vigilant follow-up is essential to promptly identify any recurrences or spreading.