Equine mammary gland disease with a focus on botryomycosis: A review and case study

Abstract

Summary Mammary gland problems occur incidentally in horses and one of the rarer conditions is botryomycosis (bacterial pseudomycosis, bacterial granuloma, staphylococcal pseudomycetoma). This article includes a short review of equine mammary gland problems inappropriate lactation, mastitis and neoplasia and botryomycosis, and additionally 2 clinical cases of botryomycosis of the udder resulting from Staphyloccocus aureus infection will be discussed. Both cases involved nonpregnant, nonlactating mares referred for chronic mammary inflammation with draining abcessation. In both mares, botryomycosis caused by S. aureus was confirmed by histopathology and a bacterial culture. Both mares recovered fully after surgical hemimastectomy under general anaesthesia.

Mammary botryomycosis: two concomitant cases in mares: case report

“…Botryomycosis lesions may be solitary or multiple, and often involve ulceration and fistulas (Scott, 1988;Cudmore et al, 2012). Reports of botryomycosis in horses have included cases involving skin, spinal canal, and mammary gland (Scott, 1988;Ellenberger et al, 2006;Cudmore et al, 2012;Smiet et al, 2012). Smiet et al (2012) reported two cases in mammary gland tissue, both with a history of left MG abscess for over 3 months and the presence of S. aureus in the aspirated fluid, with a very similar clinical profile to the mares studied in the current report.…”

“…It is not a common differential diagnosis considered in cases of alteration of the mammary gland, since there is no breed, age, or sexual predisposition to this disease (Scott 1988) and the cutaneous (not the visceral) form is most common in horses (Scott, 1988;Scott and Miller 2011;Smiet et al, 2012).…”

“…Botryomycosis was first reported in horses in 1870 as a granulomatous lesion in the lung (Smiet et al, 2012), but is more commonly found in the limbs or head after skin lacerations, or in the scrotum following castration (Knottenbelt, 2009). Botryomycosis lesions may be solitary or multiple, and often involve ulceration and fistulas (Scott, 1988;Cudmore et al, 2012).…”

“…The main histopathological finding is Pyogranulomatous dermatitis and panniculitis with presence of granules in the tissue (Scott, 1988). The morphological phenomenon known as Splendore-Hoeppli may also be present, characterized by a pyogranulomatous reaction with eosinophilic granules around a necrotic area containing microorganisms or inert materials (Scott and Miller 2011;Smiet et al, 2012).…”

“…Furthermore, we observed moderate fibrosis with sporadic localized necrosis on the periphery of the lesion and hemorrhage. Thus, the diagnosis of chronic pyogranulomatous mastitis associated with the Splendore-Hoeppli reaction was indicative of botryomycosis, a rare, chronic suppurative disease with microabscess formation, characterized by the in vivo formation of eosinophilic materials around microorganisms or biologically inert material (Scott and Miller 2011;Smiet et al, 2012).…”