Extragonadal mature teratoma in a 6-months-old kitten

Abstract

Germ cell tumors can be classified as teratoma, embryonal carcinoma, yolk sac carcinoma, dysgerminomas and seminomas. Teratomas are composed by well-differentiated cells from at least two of the three embryonic layers, and are more commonly in ovaries or testicles, but can occur extragonadal. This case describes a subcutaneous mature teratoma in a 6-month-old kitten. Macroscopically, the tumor was multilobulated and firm, measuring 11 x 6,5 x 5cm; on cut surface, multiple cystic cavities, solid white areas and hard portions. Histologically, cells derived from the three layers were present – hair follicles and glands, nervous tissue, odontogenic epithelium, respiratory epithelium, and different mesenchymal cells (bone, adipocytes, muscle fibers and fibrous tissue). Immunolabeling for pancytokeratin, vimentin, GFAP and p40 were strong in the different types of cells, and no immature tissue was seen. So, the tumor was classified as a mature extragonadal teratoma. The mass was completely excised and no recurrence was seen.