MIXED TUMOR OF THE VAGINA

A 33-year-old Japanese woman presented with a polypoid 2.5 x 2.5 x 1.9 cm mass located in the posterior wall of the lower vagina. Microscopi cally, the tumour was composed of benign epithelial and stromal-type e lements. Predominant epithelial elements were mucinous glands with squ amous metaplasia and islands of mature squamous epithelium. The stroma l-type cells showed reticular or short fascicular patterns with a tran sition to the epithelial elements. There was no dual epithelial-myoepi thelial combination in the glands as seen in so-called mixed tumours ( pleomorphic adenomas) of the salivary gland. Immunohistochemically, th e epithelial elements were strongly positive for cytokeratin, PKK1 and epithelial membrane antigen, while the stromal-type cells co-expresse d PKK1 and vimentin. Staining for S-100 protein, muscle actin, alpha-s mooth muscle actin, desmin, and CD34 was uniformly negative in the tum our cells. The DNA pattern was diploid. The patient is alive and well without recurrence for 50 months after excision. These results indicat e that an epithelial cell proliferation, probably of the remnant vesti bular gland, plays a major role in the development of mixed tumours of the vagina.