Localized Coagulative Myonecrosis Presenting as a Discrete Thigh Mass in a Captive Red Tegu (Salvator rufescens)

Abstract

A discrete, firm mass was identified on the dorsal aspect of the right thigh of an adult female Red Tegu (Salvator rufescens) maintained at Sardar Patel Zoological Park, Gujarat, India. The swelling had enlarged slowly over approximately four months, while the animal remained clinically stable with normal appetite, locomotion, and behaviour. There was no recorded history of trauma, intramuscular injection, or recent local treatment. Physical examination showed a well-circumscribed, non-fluctuant, non-painful mass approximately 3 cm in diameter, and radiography demonstrated a hyperdense lesion without orthopaedic involvement. Surgical excision was performed under isoflurane anaesthesia. Gross examination revealed a round, firm, well-demarcated intramuscular mass with a pale white-to-grey, dry, homogeneous cut surface. Microbiological analysis of a surgical-site swab showed no bacterial growth. Histopathological examination demonstrated a sharply demarcated focus of coagulative myonecrosis characterised by intensely eosinophilic, hyalinised myofibres, loss of cross-striations and nuclear detail, preservation of overall tissue architecture, and a thin fibrous capsule. Inflammatory infiltration was minimal, and no neoplastic proliferation, granulomatous reaction, parasitic structures, vascular thrombosis, or significant haemorrhage was identified. The surgical wound healed without complication, and no recurrence was observed during six months of follow-up. This case demonstrates that localised coagulative myonecrosis can present clinically as a discrete tumour-like muscular mass in a captive Red Tegu and supports histopathological examination for definitive lesion characterisation.