Sebaceous carcinoma (SC) is a rare and aggressive form of cutaneous malignant tumour that is commonly misdiagnosed. SC most frequently affects the head and neck region, and is classified based on anatomical location, either ocular or extraocular.1 SC can have a diverse clinical presentation, but typically presents as a slow growing, firm papule of varying colour.2 Due to its nonspecific presentation and aggressive nature, clinicians must be mindful of a potential SC diagnosis. SC has an association with Muir-Torre Syndrome, a form of Lynch Syndrome, and mismatch repair studies and additional cancer screening may be necessary.2
A 71-year-old male presented to his General Practitioner (GP) with a 12-month history of a lesion on his lower lip. A 2mm x 2mm punch biopsy was performed demonstrating superficial eroded intraepidermal carcinoma. The patient was referred to a dermatologist, who noted induration of the region, querying invasive squamous cell carcinoma. Shave biopsy of the mid lower lip mucosa just inside the vermillion demonstrated features of sebaceous carcinoma on histopathology, which was confirmed with immunohistochemistry. The patient was referred to an ear nose and throat surgeon, who performed a wedge excision, with the SC lesion measuring 10mm across and 1.4mm thick. The case was referred to a multidisciplinary head and neck meeting, where suggestion was made to have at least 3mm clearance margins.
This case highlights the importance of considering SC as a differential for atypical head and neck lesions and will summarise current literature regarding SC and management options including Mohs micrographic surgery.