Primary cutaneous mucinous carcinoma of the scalp masquerading as a benign dermatological mass - A case report.

INTRODUCTION AND IMPORTANCE: Primary cutaneous mucinous carcinoma (PCMC) is a rare low-grade malignant neoplasm derived from the sweat glands. Local recurrence of PCMC occurs frequently, but these lesions rarely metastasize. Due to the absence of classical demographic and clinical characteristics, PCMCs masquerade as sebaceous cyst, lipoma, pilomatrixoma, chalazion, or squamous cell carcinoma. This misdiagnosis frequently leads to incomplete surgical excision which necessitates further surgical therapy for a curative intent.

CASE PRESENTATION: We present a case of PCMC in a 45-year-old woman which presented as a slow- growing and symptomless nodule in the scalp. After clinical evaluation, the patient had a typical surgical excision for a benign-looking lesion. Histological evaluation of the specimen confirmed a localized PCMC in the scalp with involved surgical margins.

CLINICAL DISCUSSION: A thorough oncological assessment by PET-CT scan and radionuclide scintigraphy was performed. Later, a wide local excision using a gamma probe for intra-operative radionuclide localization of the tumor area and sentinel lymph nodes was done.

CONCLUSION: The patient did not have any regional or distant metastases and remained stable at the time of reporting this case.