[Clear cell adenomyoepithelioma of the ceruminous gland]

Ceruminous gland tumours are rare neoplasms. We describe a case of a ceruminous tumour with complex morphology characterised by fibrous hyaline stroma bilayered epithelial ductal structures and nodules of tightly arranged clear cells with abundant Pas-positive cytoplasm. Within nodules among clear cells delicate apocrine ducts were found. Stromal tongues infiltrated with lymphocytes invaginated into nodules producing a lymphadenomatous pattern. Among clear cells, there are also numerous eosinophilic, Pas-positive refractile crystalline inclusions that appeared as floral petals (gerbera) or as a firework-like pattern. By immunohistochemistry, ductal structures were reactive for CK pan, CK7, CK18, CK19, EMA and GCDFP-15. Epithelial ductal basal cells were reactive for CK5, p63, calponin and SMA. Clear cells were weakly positive for CK18 and strongly positive for vimentin; they also displayed S100 protein and focal GFAP immunoreactivity. Interestingly clear cells lacked immunostaining for calponin, p63, caldesmone, SMA and MSA. This result supports the myoepithelial nature of clear cells, which have lost some antigenic specificities, and the diagnosis of adenomyoepithelioma of the ceruminous gland. The lesion appears morphologically benign. The patient is a 47-year-old woman with no evidence of disease after 3 years of follow-up.