Unique orbital biphenotypic tumour with neuroendocrine and sebaceous carcinoma features

A 60-year-old female presented with a large, left upper eyelid mass that had rapidly expanded in the 3 months prior to presentation. She had a presumed chalazion excised from the same area 1.5 years ago, but no pathology was investigated. On examination, she had a palpebral mass measuring 4.5 cm x 3.5 cm that abutted the globe with extensive conjunctival involvement. Neuroimaging demonstrated lesions concerning for parotid gland metastases. An incisional biopsy demonstrated synaptophysin-positive small blue cells concerning for neuroendocrine carcinoma. The patient underwent orbital exenteration with parotidectomy and radical neck dissection. The excised mass was found to have distinct neuroendocrine carcinoma cells intermingled with sebaceous carcinoma cells, a combination not previously reported.