An extragonadal teratoma in a female cynomolgus monkey (Macaca fascicularis)

Investigation of extragonadal teratomas in two Poecilia wingei

Teratoma is a rare tumour in fish consisting of tissues from more than one germ layer, that may be located in either the gonads or extragonadal sites. Teratomas in many fish species remain poorly understood. In this work, we performed the first histological examinations of extragonadal teratomas in Poecilia wingei and also examined the influence of a large teratoma on male sexual activity. The studied teratomas shared general organizational features, but they also had variations in both external and internal features. In teratomas, the most common and highly differentiated tissues were striated muscle and nervous tissue. Despite the tumour, the male P. wingei exhibited normal mating behaviour and retained the ability for successful copulation. The structural features of extragonadal teratomas in guppy fish indicate a possible connection between these tumours and a failure of conserved processes operating in the embryonic germline.

Bladder teratoma in a maned wolf (Chrysocyon brachyurus)

Background

Teratomas are germ cell tumors, comprised of a mixture of tissue types and with tissue foreign to their site of origin.

Case Description

A 5.5-year-old intact female maned wolf (Chrysocyon brachyurus) was treated for recurrent stranguria and suspected cystitis. Due to lack of resolution, the wolf was anesthetized for further evaluation. The urinary bladder was firm on palpation, with a markedly thickened wall and no observable lumen on ultrasound. Neoplastic infiltration was suspected on double contrast cystogram and confirmed via surgical exploration. The lesion was inoperable and the wolf was euthanized. Gross necropsy revealed two poorly distinguished masses infiltrating the urinary bladder dorsally and caudoventrally, with minimal remaining lumen. Histopathologic examination of the bladder and associated masses revealed a neoplasm comprised of multiple tissue types. Vascular invasion was noted.

Conclusion

The neoplasm was diagnosed as an extragonadal teratoma. Few extragonadal teratomas have been described and this is the first report of a teratoma originating in the urinary bladder of a non-human species.