Adenocarcinoma Metastasis of the Intertransversarius Cervicis Muscle Eliciting a Right Forelimb Lameness in a Dog

This article describes identification of a metastatic adenocarcinoma to the intertransversarius cervicis muscle using magnetic resonance imaging (MRI) in a dog that presented with chronic lameness of the right forelimb. Magnetic resonance imaging revealed a right sided, ovoid signal abnormality within the intertransversarius cervicis muscle lateral to the sixth cervical (C6) vertebra. The lesion was uniform, hyperintense on T2‐ and isointense on T1‐weighted images to muscle and exhibited uniform contrast enhancement on T1‐weighted images. The MRI findings were consistent with a neoplasia. Surgical excision was performed. Histopathological diagnosis was metastatic fibrous adenocarcinoma. The dog recovered rapidly but 6 months post‐operatively he was killed because of lung metastases. Necropsy was declined and the primary tumour could not be identified.