Mammary carcinoma in a ewe

Mammary Adenoma Associated with Chronic Mastitis in a Wild Boar (Sus Scrofa)

Mammary gland tumor is rare and only a few cases have been reported in wild animals. Moreover, most etiologies of the known cases in veterinary medicine are related to age, diet, obesity, and excessive sex hormones in domestic animals while few etiologies are reported in wild animals. An unknown-aged female wild boar was presented to the Department of Veterinary Pathology, Kyungpook National University with a well-demarcated, and firm-to-elastic mammary gland mass. The cut-surface of the mass was pink-reddish, and homogeneous. Microscopically, the mass was mainly composed of well-differentiated neoplastic glandular epithelial cells characterized by a single-layer, columnar to cuboidal shapes, and small and central nuclei and nucleoli. Any evidence of invasiveness or metastases of the neoplastic cells were not observed. Interestingly, infiltration of chronic inflammatory cells such as plasma cells and macrophages was observed along with a large quantity of gram-negative and positive bacterial colonies in the mammary glands. Moreover, accompanied fibrosis of stroma was observed, as well. Based on the gross and microscopic findings, the present case was diagnosed as mammary simple adenoma caused by chronic mastitis progressing to fibrotic condition. To the authors’ knowledge, this is the first study describing the histopathological aspects of mammary gland tumors associated with chronic mastitis accompanied by fibrosis in wild animals.

Mammary carcinoma arising in an adenoma in a ewe

A large, firm, multi-cystic mammary gland mass grew slowly over 4 y in a 12-y-old, female Finn-Shetland cross sheep. A diagnosis of epithelial malignancy was suspected following fine-needle aspiration cytology at 30 mo after initial observation. The sheep was euthanized when the flock was downsized 18 mo later. A field postmortem examination revealed a large mammary mass, but an absence of metastases to internal organs. Imprint cytology of the mammary tissue supported a benign proliferative process. Histologically, mammary tissue was obliterated by cystic, tubular, and papillary adenomatous arrangements of mammary epithelium, with an anaplastic component, consistent with mammary carcinoma arising in an adenoma. IHC showed strong nuclear positivity to the antibody against progesterone receptor and minimal positivity to the antibody against estrogen receptor alpha expression. Intrinsic subtyping for basal or luminal epithelial origin was attempted through adaptation of companion animal IHC classification panels; high- and low-molecular-weight cytokeratins (CK5, CK8, CK18) failed to stain, but p63 expression for basal epithelium was positive.

Comparative mammary gland postnatal development and tumourigenesis in the sheep, cow, cat and rabbit: Exploring the menagerie

Sheep, cows, cats, and rabbits are kept by humans for agricultural purposes and as companion animals. Much of the mammary research in these species has focussed on mastitis in the case of ruminants and rabbits, and mammary tumourigenesis in cats and rabbits. However, similarities with the human breast suggest that these species may be currently underutilised as valuable comparative models of breast development and disease. The mammary gland undergoes cyclical postnatal development that will be considered here in the context of these non-traditional model species, with a focus on the mammary microenvironment at different postnatal developmental stages. The second part of this review will consider mammary tumour development. Ruminants are thought to be relatively 'resistant' to mammary tumourigenesis, likely due to multiple factors including functional properties of ruminant mammary stem/progenitor cells, diet, and/or the fact that production animals undergo a first parity soon after puberty. By contrast, unneutered female cats and rabbits have a propensity to develop mammary neoplasms, and subsets of these may constitute valuable comparative models of breast cancer.

Infectious Agents in Bovine Red Meat and Milk and Their Potential Role in Cancer and Other Chronic Diseases

Red meat and dairy products have frequently been suggested to represent risk factors for certain cancers, chronic neurodegenerative diseases, and autoimmune and cardiovascular disorders. This review summarizes the evidence and investigates the possible involvement of infectious factors in these diseases. The isolation of small circular single-stranded DNA molecules from serum and dairy products of Eurasian Aurochs (Bos taurus)-derived cattle, obviously persisting as episomes in infected cells, provides the basis for further investigations. Gene expression of these agents in human cells has been demonstrated, and frequent infection of humans is implicated by the detection of antibodies in a high percentage of healthy individuals. Epidemiological observations suggest their relationship to the development multiple sclerosis, to heterophile antibodies, and to N-glycolylneuraminic acid (Neu5Gc) containing cell surface receptors.