[Sebaceous cutaneous carcinoma. Value of early cytological test]

Sebaceous carcinoma is a skin tumour which frequently metastases to the visceral organs. Needle biopsy is needed for rapid diagnosis. We observed a case in a 65-year-old patient who had a tumour formation below the right maxillary angle and homolateral justamandibular lymph node enlargement. Cytology of the needle biopsy showed a double cell population: small anaplastic cells and an agglutinated cell mass with peripheral maturation and sebaceous differenciation. Treatment was surgical with homolateral node dissection and secondary plasty. The tumour was large, non-encapsulated with local infiltration. On light microscopy, two cell populations were seen. Evident sebaceous differentiation was confirmed by histochemical staining. Immunolabelling confirmed the epithelial nature of the tumour. The clinical diagnosis of sebaceous carcinoma is difficult. Early cytology is needed to identify the two cell components when other cytological signs do not allow a positive diagnosis.