A rare case of soft tissue leiomyosarcoma with liver metastases in a rose-ringed parakeet (Psittacula krameri).

Leiomyosarcoma (LMS), a relatively rare malignant tumor that arises from smooth muscle cells in various soft tissues, was found in a 3-year-old female rose-ringed parakeet. A clinical examination revealed a mass extending from the right thigh region to the caudal aspect of the right abdomen, accompanied by swelling, as demonstrated by radiography. Gross appearance of the tumor showed a well-circumscribed yellowish and nodular round mass with a creamy structure and gelatinous surface. After excision of the mass, histological examination revealed a spindle-cell mass infiltrating the thigh muscles, with nuclear variation, necrosis, and lymphocyte infiltration in some tumoral sections. Routine immunohistochemistry investigations were performed, revealing positive tumor cell expression for alpha-smooth muscle actin (α-SMA), myogenin, and desmin markers. Histopathological and immunohistochemical evaluation of the hepatic section confirmed LMS, indicating metastatic foci originating from the primary soft tissue leiomyosarcoma in the thigh region. Based on our knowledge, this is the first reported case of leiomyosarcoma in this species and among the rare reports of smooth muscle neoplasms occurring in the hind limb of birds.