Page 520 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Reproductive system: 2.1 The female reproductive tr act 495

VetBooks.ir perineal skin. They can be malignant, spreading between the vulval lips. Usually, they have a pedun-
Polyps/papillomas are seen protruding from
SCC is more common in mares with unpigmented
mainly to the local lymph nodes, but this seldom
vestibule or vulval lips. They can enlarge slowly to a
occurs. More usually there is local spread, especially culated neck and little surrounding reaction on the
in the ulcerative form. considerable size and may ulcerate and become sec-
Melanoma is very common in older grey animals, ondarily infected.
especially in the perineum. Most are slow growing SCCs come in two types: the proliferative type
and benign, and usually only cause problems due occurring on the vulval lips, vestibule wall and
to their space occupation. Rarely, they may become clitoral region (Fig. 2.105); and the ulcerative type,
highly malignant. found more likely on the perineum or vulval lips.
Vascular hamartomas occur mainly in the vagina Secondary infection is common, leading to further
and muscular hamartomas in the perineal muscles. tissue damage, increased odour and serosanguineous
Hamartomas are abnormal accumulations of a nor- discharge. Metastasis to other organs (lungs, verte-
mal cell type in a normal or abnormal location. They bral bodies) beyond the local lymph nodes is rare,
are benign. but may lead to other clinical signs and generalised
weight loss and illness.
Clinical presentation Melanomas usually present as typical black lesions
Leiomyomas are usually single, occasionally mul- of varying size in the perineal skin (Fig. 2.106),
tiple nodules in the wall of the uterus, varying in which may ulcerate with trauma or rapid growth and
diameter from 2 to 15 cm. They rarely cause any lead to a thick, black, haemorrhagic discharge. Some
recognisable clinical signs, except for slight bleed- mares have either a single large tumour or large
ing if ulceration occurs, and they are therefore numbers of small tumours, which can adversely
found incidentally on rectal or ultrasonographic affect intromission and parturition. Depigmentation
examination of the uterus. may suggest malignancy.

2.105 2.106

Fig. 2.105 A squamous cell carcinoma of the clitoris Fig. 2.106 Massive infiltration of the perineum, tail
and ventral vulval lips. head and dorsal vulva by a melanoma.