Metastatic mucoepidermoid carcinoma
Sorry, that is
The correct diagnosis is:
Metastatic sebaceous carcinoma with squamous differentiation
- The aspirates are cellular containing predominantly dispersed, atypical polygonal cells with a mixture of finely vacuolated and dense (squamoid) blue cytoplasm.
- The nuclei are centrally located, moderately atypical with occasional prominent nucleoli.
- The findings are consistent with metastatic carcinoma of mixed squamous and sebaceous type.
- Histologic appearances of sebaceous carcinomas can be diverse.
- This biopsy reveals a sebaceous tumour with infiltrating clusters, cords and single malignant cells with foamy, finely vacuolated cytoplasm and prominent nucleoli. There are numerous poorly-differentiated areas with monotonous sheets of cells with clear cytoplasm. Areas of squamous differentiation are also seen.
- Sebaceous carcinoma most often arises in the eyelid, presenting as a painless, enlarging mass. The median age of the patients with this tumour is 64 years and there is a higher incidence in females.
- These are rare but highly malignant neoplasms with frequent regional and distant metastasis.
- Clinically, these tumours are often mistaken for basal cell carcinomas. On cytology, basal cell carcinomas typically have more tightly cohesive clusters of uniform, hyperchromatic basaloid cells without cytoplasmic vacuolization.
- Sebaceous cells resemble mucinous cells of a mucoepidermoid carcinoma and in the presence of intermediate-type, or epidermoid cells, distinction between these two carcinomas can be difficult.
- Oil-red-O stain for intracytoplasmic lipid can be a helpful marker of sebaceous differentiation.
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Malhotra P, Arora VK, Singh N, Bhatia A. Metastatic Extraocular Sebaceous Carcinoma With an Occult Primary. Diagn Cytopathol. 2004 Nov;31(5):326-9.
Stern RC, Liu K, Dodd LG. Cytomorphologic features of sebaceous carcinoma on fine needle aspiration. Acta Cytol 2000;44:760-764.