Although various neoplasms may occur in the canine ovary, only few studies with mainly small case numbers are available (Review: Arlt & Haimar 2016). Elevated anti-Müllerian hormone (AMH) concentrations have been described in granulosa cell tumours (GCT) in women and mares, but not in dogs until now.

Aims of the study:

1.  Pathological characterization of a higher number of canine ovarian neoplasms with a correlation to breed and age

2.  Evaluation of AMH values in canine GCTs and other ovarian tumours

Ovarian neoplasms of 280 bitches (age 9±3 years) were submitted (2013–2016) for histopathological routine diagnosis, including macroscopic and immunohistochemical (cytokeratin, CD3, CD79a, CD31, actin) investigations.

In 21 cases, preoperative serum samples were available for retrospective AMH value measurements with an automated chemiluminescense-immunoassay.

Ovarian tumours (unilateral/bilateral) were diagnosed as GCT (86/11), ovarian carcinoma (41/23) and adenoma (32/8), teratoma (17/3), dysgerminoma (14/2), leiomyoma (6/0), leiomyosarcoma (5/0), hemangiosarcoma (3/0), stromal tumour (2/0), lymphoma (4/3), luteoma (5/0), multiple different neoplasms (4/11). Certain signs of malignancy were obvious in 23 GCTs, six dysgerminomas, one teratoma and all carcinomas, lymphomas, sarcomas and cases with multiple tumours.

Bitches with teratomas were younger (median 6 years) than dogs with other ovarian neoplasms (median 9 years).

Median diameters were 1.5 cm of normal ovaries, 3.0 cm of ovarian adenomas and carcinomas, 4.5 cm of GCTs and dysgerminomas, 5.3 cm of teratomas.

Within the ovarian tumour population, the breed groups, sheepdogs and cattledogs (FCI-1) and Spitz and primitive types (FCI-5) were represented with 14.7% and 5.3%, respectively. However, looking at all samples (AS) and percentage of all tumour samples (TS) submitted to Laboklin during the years, these breed groups were less represented: sheepdogs and cattledogs: AS 7.33% and TS 6.7%; and Spitz and primitive types: AS 7.8% and TS 1.74%.

AMH values (ng/ml) were significantly higher in GCTs (median: 5.13, 1.12 to >23.00, n=9) than in dysgerminomas (median: 0.25; 0.03–0.26, n=3), ovarian carcinomas and adenomas (median: 0.61; 0.01–0.89, n=9).

In conclusion, sheepdogs and cattledogs (FCI-1) and Spitz and primitive types (FCI-5) seem to have a predisposition for ovarian tumours. Although varying in median size and age of the bitch, ovarian neoplasms are not distinguishable by clinical or macroscopical findings. Histological investigation is needed for final diagnosis and prognosis. However, measurement of AMH serum concentration may help to identify GCT pre-surgically. Further studies will be performed to investigate AMH values in cases with ovarian cysts.

Disclosures

Disclosures to report
Several authors of this study belong to Laboklin GmbH & Co.KG - a diagnostic laboratory, which is offering the AMH measurement for clients.