HISTORY

An 3 year old primiparous half-breed female was referred at Veterinary Teaching Hospital of Murcia for evaluation of abnormal vaginal discharge and little interest in their pups. The bitch had given birth 9 normal pups 8 days previous. On physical exam the bitch was depressed and a reddish brown uterine discharge was observed. Cytologic evaluation revealed the presence of degenerated neutrophils in a high number some erythrocytes and vaginal cells. A hemorrhagic secretion from one mammary gland was observed. Haematological study showed an neutrophilic leukocytosis and an increase in ALT, AST and PA. On abdominal radiograph a soft-tissue mass (9x9.5 cm) was observed caudal to the right kidney. On ultrasonography examination the uterus was enlarged with an anechoic fluid in the lumen and no presence of placental or pups tissues. The differential diagnosis included ovarian cyst or tumour. A metritis postpartum was diagnosticated. The ovariohysterectomy was performed. Before surgery intravenous cephalothin and fluids was given. On gross examination a devitalized and enlarged uterus was observed. The size of the right ovarian mass was increased and contained a single cystic structure filled with a yellow clear fluid. The supporting stroma contained hair and on the surface there was a single corpora lutea. The histopathological findings included a cystic space that was lined by epidermis. The diagnosis was dermoid cyst, a special form of cystic teratoma. Cephalosporin was given as antibiotic. The patient was monitored for 4 weeks after surgery and the bitch remained normal.

DISCUSSION

The presence of neoplasia in canine ovarian is very infrequent, representing approximately a 1% of the tumors recorded in the dog. Teratomas are rare tumors that have been seen in all domestic species and they are germ cell tumors that have their origin in primordial germ cells from the ovary. A special form of cystic teratoma is the dermoid cyst that has not been reported frequently. The mean age at diagnosis of bitches with teratoma is 6.5 years, no breed predisposition has been reported, and the left ovary appears to be involved more frequently than the right. In our case, the affected ovary was the right, the bitch was only 3 years old and it did not present the most common clinical signs of teratomas and other ovarian tumors such as abdominal distention or a mass palpable per abdomen. The fact of being a cassual and secondary to the post-partum metritis finding could to explain the absence of these signs. The lack of influence of this tumors on ovarian function had been previously reported, because dogs with teratomas have shown normal estrous cycles. In our case, the bitch having a dermoid cyst in the ovary with a functional corpora lutea developed a normal gestation farrowing nine normal pups, confirming the ovarian hormonal activity. Surgical removal of the neoplastic ovary is the treatment of choice although complete ovariohysterectomy is recommended because of risk of metastasis (33-50% of teratomas reported). In our case, we recommended the ovariohysterectomy and the tumour was non-malignant.