Subcutaneous leiomyosarcoma in a cynomolgus macaque (Macaca fascicularis)

Abstract

AbstractLeiomyosarcoma, a malignant tumour originating from smooth muscle cells, has rarely been documented in non‐human primates. In this case study, a 7‐year‐old female cynomolgus macaque (Macaca fascicularis) presented with a rapidly growing mass overlying the left elbow joint. Radiographs indicated the presence of a soft tissue neoplasm without any associated bone involvement. The mass was surgically resected. Histological and immunohistochemical analyses revealed spindle‐shaped cells with eosinophilic cytoplasm that resembled smooth muscle cells, exhibiting positive immunoreactions for vimentin, desmin and smooth muscle actin and a negative reaction for pan‐cytokeratin. This is the first reported case of subcutaneous leiomyosarcoma in a cynomolgus macaque and provides important insights into the incidence and characteristics of this condition in this species.