A case of metastatic non-teratoid ocular medulloepithelioma in an adult horse

Abstract

This case reports an eight-years-old horse that presented a unilateral tumor in the left ocular orbital region diagnosed on the basis of clinical signs, gross anatomopathological and histopathological investigations. The affected area was exenteration and submitted to histopathological evaluation and was diagnosed as a non-teratoid medulloepithelioma. This is a rare ocular neoplasm that usually affects young individuals – and was composed by neuroepithelium arranged in tubules and Flexner-Wintersteiner rosettes without presence of heteroplastic components. The animals died and was submitted to post-mortem evaluation, revealing presence of medulloepithelioma metastases at the internal region of the head, lymph nodes, lungs, and liver. This neoplasm usually presents a benign frame; however, the case herein described shows that it can be highly malignant and aggressive since it can cause extensive lesions and spread metastases to visceral organs.

Intraocular neuroectodermal embryonal tumor in two rabbits

“…Metastasis to regional and distant lymph nodes, lungs and liver was reported in a llama, horse and dogs with medulloepithelioma 1,7,9 . In case 2, there was metastasis to the contralateral conjunctiva.…”

“…1,3 Metastasis to regional and distant lymph nodes, lungs and liver was reported in a llama, horse and dogs with medulloepithelioma. 1,7,9 In case 2, there was metastasis to the contralateral conjunctiva. The enlarged lymph nodes and respiratory difficulty leading to euthanasia were suspected to be metastasis but no postmortem evaluation was performed.…”

“…Intraocular neuroectodermal embryonal tumors (NETs) are rare and sporadically reported in dogs, cats, horses, birds and llamas. [1][2][3][4][5][6][7][8][9] As there are no reports of neuroectodermal tumors in rabbits, we describe NETs in two pet rabbits.…”

Spinal Cord Medulloepithelioma in a Cat

“…Medulloepithelioma (MEPL) is a rare, highly malignant primitive neuroectodermal tumor characterized by tubular and trabecular arrangements of tumor cells. In animals, MEPL has been mostly described as an intraocular tumor in horses [1][2][3][4], dogs [5][6][7][8][9], cats [10,11], llamas [12,13], and cockatiels [14,15], with single case descriptions in a goldfish [16], an African grey parrot [17], and a northern, red-shouldered macaw [18]. A primary intraocular neuroepithelial embryonal tumor with histological features of retinoblastoma and MEPL has been reported in two rabbits [19].…”

“…A primary intraocular neuroepithelial embryonal tumor with histological features of retinoblastoma and MEPL has been reported in two rabbits [19]. Metastases of intraocular MEPL to the brain and kidneys have been described in a dog [8] and to the lymph nodes, lungs, and liver in a horse [3] and llama [13]. Primary extraocular MEPLs in the canine spinal cord have been reported in the earlier veterinary literature [20][21][22].…”