Ocular teratoid medulloepithelioma in a northern red-shouldered macaw: case report and literature review

Abstract

A 4-mo-old northern red-shouldered macaw ( Diopsittaca nobilis) was admitted to the veterinary hospital of the Arruda Câmara Zoo, in the State of Paraiba, Brazil, for investigation of an orbital mass. Given rapid progression and lack of response to treatment, the bird was euthanized, and an autopsy was performed. Histologically, the mass consisted of a retrobulbar invasive tumor characterized by tubular and rosette-like structures, with interspersed heteroplastic tissues, such as aggregates of neuroglial cells and islands of hyaline cartilage. The tumor was immunopositive for pancytokeratin, GFAP, NSE, and S100. These findings were compatible with an ocular teratoid medulloepithelioma, a neoplasm best described in humans but also reported rarely in young cockatiels and African Grey parrots.

Intraocular neuroectodermal embryonal tumor in two rabbits

“…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.…”

“…Medulloepitheliomas have both types of rosettes or elongated tubules, and lack retinal markers. If there are non‐ocular elements (cartilage, striated muscle, neural tissue) the tumor is classified as teratoid medulloepithelioma 3,4,6,12 . There are three known cases that conflict with these criteria in veterinary species: a diagnosis of retinoblastoma was made in a llama and a horse with a tumor exhibiting both types of rosettes and both labeled positively for retinal markers (rhodopsin and Retinal S protein), and a cockatiel was diagnosed with medulloepithelioma with a tumor exhibiting Flexner‐Wintersteiner rosettes only 3,14,15 .…”

“…If there are non-ocular elements (cartilage, striated muscle, neural tissue) the tumor is classified as teratoid medulloepithelioma. 3,4,6,12 There are three known cases that conflict with these criteria in veterinary species: a diagnosis of retinoblastoma was made in a llama and a horse with a tumor exhibiting both types of rosettes and both labeled positively for retinal markers (rhodopsin and Retinal S protein), and a cockatiel was diagnosed with medulloepithelioma with a tumor exhibiting Flexner-Wintersteiner rosettes only. 3,14,15 Until genetic testing is readily available for veterinary species, differentiating these two tumors relies on immunohistochemical properties rather than histomorphology alone.…”

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].…”