A 7-year-old female Labrador presented to us at West Midlands Referrals with a large soft tissue mass, a leiomyosarcoma (a malignant tumour of smooth muscle cells), in the perineum (the area between the vagina and the anus).
It originated from the dorsal vaginal wall very close to, and just in front proximal of, the urethra on the ventral aspect. She also had an ovariohysterectomy. A catheter was placed into the urethra to aid surgical navigation and maintained for a week post-op. At that time, she managed to urinate well and is knowingly defecating in the garden.
The histological appearance was consistent with a leiomyosarcoma, which appeared to have been completely excised with narrow margins.
Leiomyosarcomas are uncommon tumours that tend to be locally infiltrative but are only occasionally metastatic. The prognosis largely depends upon the ability to achieve local tumour control.
A year later, we followed the case up by phone, and the owner advised there was no sign of recurrence – no straining etc.
Warning: images below are pretty graphic. The area has a good blood supply, so there can be a significant need to control bleeding.