Pulmonary adenofibroma in a sika deer.

A solitary firm nodule was found in the lung of a sika deer (Cervus nippon yesoensis). Histologically, it was a biphasic lesion composed of epithelial and stromal cell elements and exhibited a leaf-like growth pattern. The epithelial cells were immunohistochemically positive for pancytokeratin, cytokeratin 7, napsin A, and thyroid transcription factor-1, and the stromal cells were positive for vimentin and partially positive for desmin and α-smooth muscle actin. These observations were consistent with pulmonary adenofibroma, which is an extremely rare lesion in humans. To the best of our knowledge, this is the first reported case of pulmonary adenofibroma in an animal.

Aglepristone: A review on its clinical use in animals.

Aglepristone (RU 46534) is a competitive progesterone antagonist that is indicated for the treatment of various progesterone-dependent physiological or pathologic conditions. Aglepristone has proven to be an effective means of terminating pregnancy in most species. When used to induce parturition, aglepristone was effective in all cases in the bitch, cow, and goat, with no apparent adverse effects on neonatal health or milk production. When used to schedule an elective cesarean section, aglepristone treatment was deemed safe for dams and puppies, providing that the ovulation date had been accurately assessed at the time of breeding. Irrespective of the stage of pregnancy at injection, treatment with aglepristone has no apparent negative effects on subsequent fertility. Aglepristone is also a safe and relatively effective means of treating pyometra. However, given the high level of septic risk and the likelihood of rapid deterioration, such therapy is not recommended in emergency situations. Treatment of feline fibroadenomatosis using aglepristone has given promising results, but repeat treatment may be necessary in cats previously treated with long-acting progestagens. The use of aglepristone in other progesterone-dependent diseases has yet to be fully evaluated but may prove valuable, especially in the treatment of insulin-resistant diabetes mellitus, acromegaly, and the treatment of some vaginal tumors in the bitch.

Adenomyofibroma of the fimbria in a cynomolgus monkey (Macaca fascicularis).

A 20-year-old female cynomolgus monkey (Macaca fascicularis) was presented for an end-of-study necropsy. At necropsy, a 2 cm x 1.5 cm x 1 cm, butterfly-shaped, multilobulated mass extended off the right uterine tube fimbria. Microscopically, the mass was composed of large, plump, finger-like projections lined primarily by simple columnar ciliated epithelium. The interstitium contained a proliferation of smooth muscle stromal cells admixed with varying amounts of collagen. A diagnosis of adenomyofibroma of the fimbria was made. This benign neoplasm should be considered as a differential diagnosis for masses arising from the fallopian tube in old-world macaques.

Reversible fibroadenomatous mammary hyperplasia in male and female New Zealand white rabbits associated with cyclosporine A administration.

All male and female New Zealand white rabbits in a limbal cell graft study developed marked generalized mammary gland hypertrophy. Postprocedural medications included ophthalmic 0.1% dexamethasone, ophthalmic 0.5% cyclosporine, and subcutaneous cyclosporine A. Cytologic examination revealed epithelial clusters with minimal malignant criteria. On histologic evaluation, there was diffuse glandular hyperplasia with mild cellular atypia and ductal ectasia separated by abundant hypercellular fibrous stroma, consistent with fibroadenomatous mammary gland hyperplasia. The hyperplasia resolved within 2 weeks of cessation of cyclosporine, and at necropsy identifiable mammary masses were not found. Very little has been reported about the use of cyclosporine in laboratory rabbits and its association with development of mammary gland hyperplasia. This is the first report in which administration of cyclosporine to male and female rabbits at a dose as low as 5 mg/kg/day induced benign fibroadenomatous mammary gland hyperplasia. This change regressed after cessation of the drug.

Hepatic biliary adenofibroma: a hitherto unrecognized tumor in equines. Report of a case.

Hepatic biliary cystadenoma is a well-delineated neoplasm in some domestic animals, especially in cats, but it has not been reported in equines. We report on a case of hepatic biliary tumor, incidentally found in a 10-year-old horse, with gross and microscopic features similar to those observed in biliary adenofibroma of humans. The tumor presented as a solid mass measuring 16 cm in diameter and histologically was composed of complex tubulocystic biliary components embedded in an abundant fibrotic stroma. We regarded this tumor as a morphological variant of biliary cystadenoma of domestic animals. Differential diagnoses from other hepatic biliary tumor-like and tumor lesions are provided.

Expression of stratified squamous epithelia-type cytokeratin by canine mammary epithelial cells during tumorigenesis: type I (acidic) 57 kilodalton cytokeratin could be a molecular marker for malignant transformation of mammary epithelial cells.

Two monoclonal antibodies (MAbs) were established in 20 clones of MAbs generated against cytokeratin fraction extracted from canine squamous cell carcinoma to investigate the expression of intermediate filament proteins during tumorigenesis. These MAbs were confirmed to react with purified cytokeratin by ELISA. One monoclonal antibody, MAb32 reacted all layers of epidermis except the cornified layer and mammary myoepithelial cells but not any epithelial cells. Another antibody named MAb24 exclusively reacted the basal monolayer of epidermis, the stratum germinativum. Any positive reactions with MAb24 were not detected in normal mammary gland. From the analysis by two-dimensional gel electrophoresis followed by immunoblotting, it was revealed that MAb24-recognizing cytokeratin subunit gave a molecular weight of 57 kilodalton and a isoelectric-pH value of pI5.1, indicating type I (acidic) cytokeratin. In intraductal papillomas developed in canine mammary glands, most tumor cells were positively stained with MAb32 in addition of myoepithelial cells while no positive reaction with MAb24 was seen. In ductal carcinomas, MAb24-positive cytokeratin was begun to express by tumor cells with positive reaction of MAb32 where these cells showed infiltrative growth into the stroma. We therefore proposed that 57 kilodalton-type I cytokeratin was a molecular marker for malignant transformation in canine mammary tumor and these antibodies could be useful tools to investigate the change of cytokeratin expression during tumorigenesis.

Cytokeratins as markers of initial stages of squamous metaplasia in feline mammary carcinomas.

Expression of keratins (cytokeratins, CK) known to be suitable markers for different types of epithelial differentiation was analyzed in specimens of feline mammary tissue. A panel of specific anti-CK monoclonal antibodies (MAb) was used to determine CK distribution pattern in normal feline tissues (n = 3), and in benign (n = 18) and malignant (n = 20) feline mammary tumors. In selected tumors, the CK distribution pattern was also determined by biochemical methods. A MAb specific for alpha-smooth muscle actin was used to discriminate between myoepithelial cells and luminal epithelial cells. In normal mammary gland tissues, 6 MAb reacted exclusively, either with myoepithelial cells or with luminal epithelial cells. Luminal epithelial cells reacted with MAb specific for CK typical of simple epithelia, whereas myoepithelial cells reacted with MAb specific for CK in basal cells of stratified epithelia. A similar distribution of CK was detected in specimens from benign tumors, except that CK4 was not detected in normal mammary gland tissues and was detected in some ducts in specimens with adenosis. Almost all tumor cells in specimens from malignant tumors reacted with MAb specific for CK typical of simple epithelia. Concomitant expression of CK typical of stratified epithelia was detected in small or large subpopulations of tumor cells in 70% of carcinomas. Cytokeratins typical of basal cell layers and typical for suprabasal layers of inner stratified epithelia were detected. Cytokeratins typical of stratified epithelia were always found in areas of squamous metaplasia, but also were found in adenocarcinomal cells surrounding these areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship of body-weight gain to longevity and to risk of development of nephropathy and neoplasia in Sprague-Dawley rats.

The relationship of weight gain to survival, risk of development of chronic progressive nephropathy and risk of development of various neoplasms has been studied in the control groups from two routine chronic toxicity studies in Sprague-Dawley rats. The groups comprised 100 CFY strain rats of each sex observed up to the age of 109 wk and 120 CD strain rats of each sex observed up to 111 wk of age (females) or 121 wk (males). The eventual incidence of tumours was found to be related to body weight at several ages. There was also a statistically significant association between high body weight at various ages and increased mortality, particularly in the CD strain and particularly in females. The 'heavy' rats proved to have an increased risk of developing both progressive nephropathy and certain tumours. This relationship was particularly marked for pituitary tumours in both sexes and for benign and malignant mammary tumours in females, and was significant irrespective of whether tumours coexisting with marked or severe progressive nephropathy were classified as fatal or incidental. There was also some evidence that increased body weight was positively associated with risk of islet-cell tumours and lipomatous tumours in males and fibromatous tumours in females. The observations illustrate how non-specific factors, such as those that affect body weight, may profoundly influence mortality and tumour incidence in chronic toxicity studies. The findings also highlight the difficulty of classifying particular neoplasms as incidental or fatal where other potentially life-threatening pathology (e.g. progressive nephropathy) is present.

Feline mammary hypertrophy/fibroadenoma complex: clinical and hormonal aspects.

Abnormal mammary enlargement, characterized microscopically by hyperplasia of both epithelial and mesenchymal tissues, was studied in 26 cats which were mostly young, sexually intact females. Clinicopathologic data indicated that mammary hypertrophy was likely progesterone-dependent. Administration of progestins preceded this condition in 5 cats, 4 of which were neutered. Serum progesterone concentrations (6.7 ng/ml) were increased in 1 of the 3 cats tested. Estrogen receptors were not found in the cytosols or nuclei of mammary tissues in the 2 cats studied. However, there were convincing 4S [3H]progesterone or 5S [3H]R5020 binding peaks which were suppressible by nonlabeled progestins. Progesterone receptors were measured at 14.9 and 8.6 fm/mg of protein, respectively. The apparent influence of progesterone, whether present as exogenous therapy in the male or female or as endogenous steroid of ovarian origin, has thus been demonstrated directly and indirectly in cats with mammary hypertrophy.

[Spontaneous tumors in aged SD-JCL rats (author's transl)].

Incidence of spontaneous tumors was examined in 77 male and 73 female SD-JCL rats reared throughout their lifespan of 5 to 36 months. Total tumor incidences were 60% and 95% for males and females, respectively. The sex difference was mostly attributable to a high incidence of mammary tumor in females. The pituitary tumor was found in 30% of males and 66% of females aged 5 to 36 months while islet cell tumor of the pancreas and thyroid tumor occurred later and the incidence of latter was particularly high in rats lived more than 2 years. Myeloid leukemia appeared to occur as early as 5 months of age.