Ultrastructural and biochemical evaluation of adrenal medullary hyperplasia and pheochromocytoma in aged bulls

Phaeochromocytoma associated with cardiomyopathy and leukocytoclastic vasculitis in a dog

Phaeochromocytomas are rare tumours of the adrenal medulla that can be associated with various presentations. Many of the better characterized clinical signs, including weakness, tachycardia and tachypnoea, are attributable to excessive and unregulated catecholamine secretion from functional tumours. In addition to catecholamine-induced cardiomyopathy and vasospasm, the invasive nature of phaeochromocytomas can lead to occlusion of the caudal vena cava contributing to systemic cardiovascular compromise. In humans, leukocytoclastic vasculitis is a rarely reported manifestation of catecholamine excess associated with phaeochromocytomas. We now describe a dog that had an invasive unilateral phaeochromocytoma with histological evidence of myocardial damage, consistent with catecholamine-induced cardiomyopathy, and leukocytoclastic vasculitis of small vessels in a range of tissues. We conclude that catecholamine excess may have played a role in the pathogenesis of vasculitis in this case. To the best of our knowledge, this is the first documented association between phaeochromocytoma and leukocytoclastic vasculitis in a non-human species.

Proliferative changes in the adrenal medulla of aged Chinese native pigs

Four aged retired Chinese native pigs, three females and one male, estimated as over 10-year-old, were subjected to autopsy because of infertility due to aging. Grossly, nodular lesions were found bilaterally in the adrenal medulla of all four pigs. Based on the gross and the histopathological findings, they were diagnosed as either medullary nodular hyperplasia or pheochromocytoma. Immunohistochemically, proliferating cells of all these lesions were immuno-positive for chromogranin-A, indicating adrenal medulla-derived. Ultrastructurally, cytoplasmic neurosecretory granules suggestive of secretion were observed in these proliferating cells. There have been only limited numbers of reports on adrenal medullar proliferative changes including pheochromocytoma in pigs. The present cases will provide a valuable information for the characterization of similar changes in animals and human.

Histologic and Immunohistochemical Characterization of Pheochromocytomas in 20 Clouded Leopards ( Neofelis nebulosa)

Clouded leopards in North American zoological institutions have a high frequency of pheochromocytomas and were identified in 32 of 70 (45%) animals necropsied. Archival sections of adrenal gland from 20 adult clouded leopards with unilateral or bilateral pheochromocytomas collected between 1984 and 2011 were examined by light microscopy and immunohistochemistry, and case demographics were reviewed. Affected leopards were older than 10 years of age (mean, 16 years; range, 11-19 years), and males were overrepresented (12 males, 8 females). Pedigree analysis yielded no evidence for heritability. Five clouded leopards had bilateral neoplasms. Pheochromocytoma was the cause of death due to invasion of the caudal vena cava and fatal hemorrhage in 4 cases. Most pheochromocytomas were well-demarcated, nodular, and expansile masses composed of cords and packets of neoplastic polygonal cells. Five pheochromocytomas had vascular invasion, of which 4 resulted in hemorrhage that was the cause of death. One of the latter pheochromocytomas also had pulmonary metastasis. Ultrastructurally, neoplastic cells had cytoplasmic structures consistent with both norepinephrine- and epinephrine-containing granules. In all cases, neoplasms were immunohistochemically positive for chromogranin A, protein gene product 9.5, and synaptophysin. A subset of neoplasms evaluated by tissue microarray were positive for met-enkephalin and β-endorphin and negative for melan-A. Histologically, 7 of 20 (35%) clouded leopards with pheochromocytomas had retinal detachment, retinal degeneration, or intramyocardial muscular arteriosclerosis, suggestive of hypertension. Pheochromocytomas can cause mortality and may be a source of clinically significant hypertension in clouded leopards. These neoplasms share similar histologic, immunohistochemical, and ultrastructural characteristics with those of other species.

An aged bull with concurrent thyroid C cell carcinoma, adrenal pheochromocytoma and pituitary chromophobe adenoma

A Japanese Black bull aged 20 years died following progressive loss of the body weight. Pathological examination disclosed multiple endocrine tumors including thyroid C cell carcinoma with metastases to the cervical lymph nodes and lung, adrenal pheochromocytoma and pituitary chromophobe adenoma in the pars distalis. The serum calcium content was as mildly low as 8.0 mg/dl at the terminal stage. The bull had daily ingested the ration containing 1.9 times the recommended calcium amount for 8 years and 120,000 units of vitamin D(3) for 5 years prior to death. The long-term dietary intake of moderately excessive calcium with vitamin D(3) might be related to the pathogenesis of the thyroid C cell carcinoma.

Phaeochromocytoma in two coatimundi (Nasua nasua)

Two unrelated coatimundi (Nasua nasua) had bilaterally enlarged adrenal glands at necropsy, and sections of the glands from both animals had histopathological features consistent with neoplasia. They were differentiated from an adrenal cortical tumour on the basis of their light microscopical morphology, immunoperoxidase staining and electron microscopic studies and a final diagnosis of phaeochromocytoma was made. To the authors' knowledge, these are the first reported cases of phaeochromocytoma in coatimundi.

Simultaneous occurrence of multiple neoplasms and hyperplasias in the adrenal and thyroid gland of the horse resembling multiple endocrine neoplasia syndrome: case report and retrospective identification of additional cases

Neoplastic and hyperplastic disorders that affect multiple endocrine tissues in a single individual are well described in humans but less so in domestic animals. Multiple endocrine neoplasia (MEN) in humans is a genetically determined syndrome characterized by the appearance of benign or malignant proliferations within two or more endocrine glands. The primary endocrine tumors that are characteristic of MEN arise from cells that share the capacity for amine precursor uptake and decarboxylation. Here we describe the case of a 22-year-old Thoroughbred mare that died during an unattended parturition and subsequently was presented for necropsy at the University of California, Davis, Veterinary Medical Teaching Hospital. A C-cell (medullary) thyroid adenoma, pheochromocytoma, and multicentric bilateral nodular hyperplasia of the adrenal medulla were present, findings that are remarkably similar to those of human MEN syndrome. Mortality during pregnancy in women with undiagnosed pheochromocytoma is high (approximately 50%), typically because of hypertension and/or hemorrhage associated with catecholamine release from the tumor. Similarly, the mare in this report died of hemorrhage subsequent to parturition. A retrospective evaluation of endocrine tumors in horses that underwent necropsy at the Veterinary Medical Teaching Hospital from 1987 to 1997 was undertaken to identify additional possible cases of MEN in horses. Data from this retrospective evaluation suggest that coexistence of hyperplasias and neoplasias of the thyroid and adrenal glands, similar to MEN syndrome of humans, also occurs with some frequency in the horse.

Mechanisms that lead to disease of the endocrine system in animals

Endocrine glands are collections of specialized cells that synthesize, store, and release their secretions directly into the blood stream. They are sensing and signalling devices located in the extracellular fluid compartment and are capable of responding to changes in the internal and external environments to coordinate a multiplicity of activities that maintain homeostasis. Diseases of the endocrine system are encountered in many animal species and present challenging diagnostic problems. The major pathogenic mechanisms responsible for disturbances in endocrine function include: 1) primary hyperfunction of an endocrine gland; 2) secondary hyperfunction; 3) primary hypofunction of an endocrine gland; 4) secondary hypofunction; 5) endocrine hyperactivity secondary to diseases of other organs; 6) hypersecretion by nonendocrine tumors of hormone-like substances; 7) failure of fetal endocrine function; 8) endocrine dysfunction due to failure of target cell response; 9) endocrine dysfunction resulting from abnormal degradation of hormone; and 10) iatrogenic syndromes of hormone-excess. For each major category, several specific disease problems have been selected to illustrate the morphologic and functional changes that characterize the response of a particular endocrine gland to disruption of function.