engleski

Abrupt exacerbation of a mid-tail melanoma during late pregnancy in a bay Holsteiner mare

A 14-year-old bay Holsteiner mare in late pregnancy was presented for sudden exacerbation of a skin nodule noted two years previously. A punch biopsy of the 12 cm ulcerated mass revealed a few clusters of poorly differentiated cells lacking pigment and surrounded by edematous and necrotic tissue. A month after foaling the mare deteriorated significantly and was humanely euthanized. Necropsy revealed regional tumour dissemination with pulmonary and kidney metastases. Histopathological examination showed mostly polygonal, occasionally spindle neoplastic cells arranged in poorly defined packets, characterized by scant to moderate eosinophilic cytoplasm lacking melanin pigment. Neoplastic cells were immunohistochemically positive for vimentin and S-100. Some clusters of cells stained positively for pancytokeratin, with only a small number of neoplastic cells showing positive intracytoplasmic granular staining for PNL2. No expression of melan A was detected. There have been no reports of an association of anaplastic malignant melanoma exacerbation during pregnancy innon-grey horses. This case accentuates the need for an early diagnosis and therapy of tumours or any skin nodules when planning pregnancy.

horse, anaplastic malignant melanoma, pregnancy, metastases

nije evidentirano