An ~10-y-old male sheep had anorexia and progressive weight loss for ~1 mo. The sheep was emaciated, and 20 d later, became recumbent and lethargic, and was hypoglycemic (0.33 mmol/L; RI: 2.6–4.4 mmol/L). The sheep was euthanized because of poor prognosis, and submitted for autopsy. We found no gross lesions in the pancreas; however, histologically, focal proliferations of round-to-polygonal cells were separated by connective tissue into small nests. These proliferating cells, which had abundant eosinophilic-to-amphophilic cytoplasm and hyperchromatic nuclei, were immunopositive for insulin and negative for glucagon and somatostatin; the lesion was diagnosed as an insulinoma. Insulinoma has not been reported previously in sheep, to our knowledge. In addition, autopsy and histologic examination revealed the presence of an adrenocortical carcinoma with myxoid differentiation and a thyroid C-cell carcinoma. Our case indicates that multiple endocrine neoplasms can occur in sheep, as in other animal species.

An 8-y-old Labrador Retriever dog had mild ataxia of the hindlimbs 4 mo after lumbosacral dorsal laminectomy for intervertebral disk disease. Ataxia of the hindlimbs gradually worsened over the next 6 y. On autopsy, gross lesions were not recognized in the spinal cord. Histopathology revealed an intradural extraparenchymal cholesterol granuloma in the cauda equina associated with remnant nerve roots. Nerves associated with the cholesterol granuloma had axonal degeneration, myelin vacuolation, and edema. In those foci, macrophages were increased in number between nerve fibers. Immunohistochemistry for neurofilament protein and Luxol fast blue staining highlighted the presence of remnant axons and myelin sheaths within the granuloma. Inflammatory cell infiltrates in the granuloma were mainly macrophages and CD3- or CD20-immunopositive T or B lymphocytes, respectively. We conclude that the cholesterol granuloma likely formed subsequent to degenerative neuropathy in the cauda equina.

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