JPC SYSTEMIC PATHOLOGY
Signalment: (JPC #2040147): 2 year old female sex-link chicken
HISTORY: This chicken died after a two day history of listlessness. She had a history of laying rubbery eggs with tissue/blood.
HISTOPATHOLOGIC DESCRIPTION (Slide a): Ovary: Effacing 40 % of the ovary and compressing adjacent ovarian stroma is an unencapsulated, well demarcated, densely cellular, infiltrative neoplasm composed of nests of polygonal cells forming irregular tubules and acini on a moderate fibrovascular stroma. Neoplastic cells have indistinct cell borders and a moderate amount of eosinophilic cytoplasm that often contains multiple, 2-5 um, round, eosinophilic cytoplasmic granules. Nuclei are irregularly round with finely stippled chromatin and indistinct nucleoli. Islands of neoplastic cells are often surrounded by fibroblasts and abundant fibrous connective tissue (desmoplasia). Anisocytosis and anisokaryosis are mild and mitoses average less than 1 per 10 40 X HPF. Multifocally within the neoplasm are large areas of amorphous, eosinophilic material (secretory product).
MORPHOLOGIC DIAGNOSIS: Ovary: Adenoarcinoma.
HISTOPATHOLOGIC DESCRIPTION (JPC #2040148) (Slide b): Mesentery with small intestine: Multifocally infiltrating and replacing the mesentery is an unencapsulated, infiltrative, poorly demarcated, densely cellular neoplasm composed of nests of polygonal cells forming irregular tubules and acini on a moderate fibrovascular stroma. Neoplastic cells have indistinct cell borders, a moderate amount of eosinophilic cytoplasm that often contains multiple, 2-5 um, round, eosinophilic cytoplasmic granules and irregularly round nuclei with finely stippled chromatin and indistinct nucleoli. Islands of neoplastic cells are often surrounded by fibroblasts and abundant fibrous connective tissue (desmoplasia). Anisocytosis and anisokaryosis are moderate and mitosis average less than 1 per 10 40 X HPF. Scattered throughout the neoplasia are moderate numbers of lymphocytes and plasma cells.
MORPHOLOGIC DIAGNOSIS: Mesentery: Adenocarcinoma.
· Most common ovarian neoplasm of the chicken
· Only affects the left ovary, (left is functional; right is vestigial)
· Oviduct contains five regions: Infundibulum (fertilization); magnum (deposition of albumen); isthmus (deposition of membranes); uterus (shell); and vagina (transport to the cloaca)
· Incidence increases with age and is 45% in aged commercial laying hens and up to 80% by 2 years of age in some breeds
· Incidence higher in breeds with high body weight and egg weight
· Metastasis, dissemination and vascular spread occur in 50% of cases
· In turkeys, long photoperiods stimulate tumor growth and short photoperiods cause regression, leading to remission; melatonin attenuates tumor growth, making this a good model for human spontaneous adenocarcinoma
· Cell of origin thought to be overlying mesothelium or from thecal glands, interstitial cells, mesonephros or sex cord remnants
· These tumors are estrogen responsive
TYPICAL CLINICAL FINDINGS:
· Abdominal distension (ascites)
· Dyspnea, depression
TYPICAL GROSS FINDINGS:
- Ranges from small, fleshy, round enlargements of follicles to enlarged, firm, gray-white cauliflower-like ovarian masses
- Multifocal implants on serosal surfaces of pancreas, mesentery, and intestines
TYPICAL LIGHT MICROSCOPIC FINDINGS:
· Patterns include solid (most common), acinar, and papillary.
· Infrequent mitotic figures
· Intracytoplasmic intensely eosinophilic, homogeneous material (PAS-positive and mucicarmine-negative; mucicarmine – very specific for epithelial mucins, including adenocarcinomas)
· Foci of necrosis and hemorrhage
· Maturing follicles are usually absent in advanced cases
· Presumed to arise from the mesothelium of the ovary
· Pattern and cell morphology vary
· Most often acinar and tubular patterns
· Neoplastic cells may penetrate through the muscularis and spread through the abdominal cavity; the muscularis mucosa under these implants becomes hyperplastic
· Similar intracytoplasmic intensely eosinophilic,homogeneous material
ADDITIONAL DIAGNOSTIC TESTS:
· Immunohistochemistry: Cytokeratin AE1/AE3, pancytokeratin, EGFR, Lewis Y, CEA, Tag 72, and erbB-2 are all reportedly positive with immunohistochemistry
· Adenocarcinomas of oviduct origin are positive for ovalbumin, progesterone and estrogen receptors
Gross ovarian neoplasm:
- Oviductal vs. ovarian adenocarcinoma: Failure to detect tumor growth on mucosal surface of oviduct strongly suggests that the primary tumor is ovarian
- Adenocarcinoma of unknown origin
- Granulosa cell tumor: Can be very large; generally attached to the ovary by a thin stalk, yellow, lobulated, round, and encapsulated by a smooth, glistening membrane, friable; often with hemorrhage and necrosis
- Arrhenoblastoma: Seminiferous tubules proliferating within ovarian stroma; associated with sex reversal in hens; variable degrees of spermatogenesis
- Leiomyoma of the mesosalpinx: Ovarian, oviduct and uterine tumors; grow on the peritoneal surface of the oviduct or in the mesentery; single, firm, encapsulated, round masses; occur in flocks on 17 beta-estradiol
· Mesotheliomas: Lack glandular structures
- Chickens serve as a model of spontaneous ovarian adenocarcinoma in humans
- Turkeys are occasionally diagnosed with ovarian and oviduct adenocarcinomas
- Canine: Ovarian adenoma/adenocarcinoma is rare
1. Kennedy PC, Cullen JM, Edwards JF, Goldschmidt MH, Larsen S, Munson L, Nielsen S. Histological classification of the tumors of the genital system of domestic animals. In: Schulman FY, eds. World Health Organization, Histological Classification of Tumors of Domestic Animals. Vol 4. 2nd ed. Washington, DC: The Armed Forces Institute of Pathology, 1998: 24-28.
2. Reece RL. Other tumors of unknown etiology. In: Calnek BW, Barnes HJ, Beard CW, McDougald LR, Saif YM, eds. Diseases of Poultry. 11th ed. Ames, IA: Iowa State University Press; 2003: 542-547.