Ovarian Tumours

Ovarian tumours in dogs and cats are very uncommon. True reports of these tumours are unknown because most reports in literature are based on necropsy findings. The reason behind low true clinical evidence of ovarian tumours is large segment of canine and feline population is surgically neutered at an early age.

                                                                      Ovarian tumours are mainly classified into three categories, according to nature of cell origin.

·        

  Epithelial cell

·          Germ cell

·          Sex cord stromal cell

Breeds which get affected in common are Pointers, English Bulldogs, Boxers, German Shepherds, Yorkshire Terriers and Indian Hounds.

1)        Epithelial Cell Tumours-

These tumours mainly include papillary adenoma, papillary adenocarcinoma, papillary cyst adenoma and adenocarcinoma. About 40 to 60% of canine ovarian tumours fall in this category. Papillary adenocarcinoma often is associated with widespread peritoneal invasion and marked by malignant haemorrhagic effusion often misleading to ascites.

Development of malignant effusion is due to

i) Leakage of fluid through tumour capsule.

ii) Exfoliation of tumour cells resulting in transcoelomic metastatic implants that exert pressure and obstruct peritoneal and diaphragmatic lymphatics.

iii) Secretion from metastatic peritoneal implants

Papillary adenocarcinoma usually metastasizes to kidney, liver, lungs, and omentum and par aortic lymph nodes.

Cystadenocarcinomas originate from the rete ovarii and consists of multiple thin walled cysts.

2)        Germ Cell Tumours-

The ovarian primordial germ cells are responsible for ovarian        dysgerminomas, teratomas and teratocarcinomas.

Dysgerminomas arise mainly from undifferentiated germ cells and consists of ovarian primordial cells. Due to their resemblance with testicular cells they are also called as “ovarian seminomas”. These tumours grow by expansion and metastasis is often in abdominal lymph nodes. However involvement of other vital organs has been also seen.

Teratomas are mainly composed of germ cells which are differentiated in two or more germinal cell layers. So these tumours have both mature elements and undifferentiated elements resembling those of embryo. These are highly metastatic in nature and it occurs in all other vital body parts.

3)        Sex Cord Stromal Tumours-

These tumours arise from the specialised gonadal stroma of the ovary, which is responsible for oestrogen and progesterone production. Most common sex cord stromal tumour is “Granulosa Cell Tumour”.

These are firm, lobulated and grow quite large size, have good metastatic potential. They are quite potential to elaborate steroid hormones.

Alpha-inhibitin, a gonadal glycopeptides known to be feedback inhibitor of pituitary secretion of follicular stimulating hormone (FSH), is a useful histologic marker of Granulosa cell tumour.

The other stromal cell tumours like Thecomas and Luteomas are also reported and are benign in nature.

Other tumours like conditions which are found are par ovarian tumours which originate from mesonephric tubules, cystic rete tubules, vascular haematomas and adenomatous hyperplasia of rete ovarii.

Depending upon the tissue of origin the clinical symptoms of ovarian tumour vary. Main clinical symptom of epithelial cell tumours is malignant ascites. Germ cell tumours are associated with hormonal dysfunction and space occupying mass in abdomen. Routine abdominal radiographs show enlarged mass with calcified foci. Stromal tumours secrete steroid hormones hence excessive oestrogen hormone leads to vulvar enlargement, sanguineous vulvar discharge, persistent oestrous, alopecia and aplastic pancytopenia. Excessive progesterone production leads to cystic endometrial hyperplasia/ pyometra complex.

The common diagnostic techniques are abdominal radiography and ultrasonography. Cytological evaluation of the malignant effusion from abdomen gives better idea.

Palliative radiation and chemotherapy using platinum based combinations with taxanes is useful in human patients but radical surgery remains the mainstay of treatment for ovarian tumours in canines.

Complete ovariohysterectomy is recommended. During surgery you have to gentle in handling tissues to minimise transcoelomic tumour spread. Before abdominal closure careful examination of all serosal surfaces, including omentum, diaphragm is necessary. Any suspected lesions should be subjected to biopsy, FNAC for metastatic disease. Before closure of abdominal incision a through wash with ample of NS is advisable.

Prognosis is very good after surgery if no metastasis and adhesions are noticed.