Fibrous vaginal hamartoma in a newborn calf

Abstract

A 2-day-old female Holstein calf was presented for abnormal structures protruding from the vulva at birth. A diagnosis of fibrous vaginal hamartoma was made, based on macroscopic and histologic examinations of the abnormal tissue. Management of this case involved surgical mass ablation.

A 2-day-old female Holstein calf was referred to the Centre Hospitalier Universitaire Vétérinaire of the Université de Montréal for the presence of abnormal structures at the vulva at birth. The calf was not premature. The calving was normal and the calf received colostrum (4 L) within the first 6 h of life.

Case description

On admission, the animal was alert and responsive. Heart and respiratory rates were within normal limits and rectal temperature was 39.2°C. Multiple cystic-like masses were protruding through the vulva (Figure 1). Digital examination of the vagina and vaginoscopy were performed after sedation of the calf with xylazine (Rompun 20 mg/mL injectable; Bayer Healthcare, Bayer, Toronto, Ontario), 0.05 mg/kg BW, IV, and epidural sacrococcygeal local anesthesia with bupivacaine (Marcaine 0.5%; Hospira Healthcare Corporation, Montreal, Quebec), 1 mL. The masses were attached to the floor of the vestibulovaginal junction by a stump approximately 3 cm in diameter. The calf urinated normally during the physical examination. Rectal ultrasonography was attempted to evaluate the reproductive tract, but the integrity of the complete genital tract could not be ascertained. Enbloc resection of the masses was performed the following day with the same anesthetic protocol and samples were submitted in 10% buffered formalin for histopathological examination. The calf was discharged from the hospital the following morning.

Figure 1.

Rear view of a 2-day-old calf with vaginal masses protruding through the vulva in a pendulous fashion.

On gross examination, the resected tissue was composed of multiple cords, 5 to 15 cm long, often ending as cystic structures filled with translucent liquid and sharing a common origin on a pedunculated base dotted with smaller papillary lumps. Histologically, all these structures were composed of well-vascularized fibrous tissue, similar to the tunica propria-submucosa of the vaginal wall and lined with stratified squamous epithelium (Figure 2). The chorion showed a variable degree of edema and mucinosis. Other changes observed included neutrophilic infiltration, dilated blood vessels, hemorrhages, vasculitis, and thrombosis. Some of the cords showed total or partial coagulation necrosis with their surface epithelium ulcerated and replaced by a thick layer of bacteria. The cystic appearance of the extremity of some masses was the result of a marked edema and liquefaction of its central part, which became progressively distended with a clear liquid.

Figure 2.

Histological appearance of the vaginal outgrowth showing well-vascularized fibrous connective tissue covered with a stratified squamous epithelium. HEPS stain. Bar = 300 μm.

Discussion

From these findings, this tissue overgrowth was diagnosed as fibrous vaginal hamartoma. Hamartoma is a developmental anomaly resulting in the formation of a mass composed of tissues normally present in the locality of the mass, but of improper proportion and distribution, often with dominance of 1 type of tissue (1). These benign tumor-like tissue overgrowths may be congenital or develop later in life. Reports of vaginal hamartoma in animals could not be found in the literature. However, although not reported as hamartoma per se, McEntee (2) briefly described 4 cases of vestibular masses found in young heifer calves and referred to the anomaly as “vestibular wattle.” From the descriptions provided, these may represent other examples of vaginal hamartoma in young calves. Overall, fibrous vaginal hamartoma, as described in this report, appears to represent a rare entity. In the bovine species, cases of vascular hamartoma, also called juvenile bovine angiomatosis, have been more commonly reported (3,4). These vascular lesions (often congenital) have been described in a variety of tissues, most notably within the gingiva.

Management of this case involved surgical mass ablation. At the age of 9 mo, the heifer was growing normally and no masses had reappeared.

The heifer grew up normally afterwards and no mass reappeared. At the age of 15 mo, the heifer was inseminated and has been declared pregnant at 17 mo.