Case report: Rhabdomyosarcoma in a seven year old male Rottweiler

Abstract

A rare case of embryonal rhabdomyo-sarcoma was diagnosed in a seven year old male Rottweiler presented with a soft sub-cutaneous swelling of about 20cm x 12 cm around the distal thoracic region on the left side. On aspiration the swelling yielded blood exudate. Sonographic examination of the swelling revealed a central anaechoic area with some reflectors  surrounded by hypoechoic area with underlying hyperechoiec structure. Thoracic radiograph showed normal interstitial pulmonary pattern with no evidence of metastasis. In addition, there was no evidence of rib fractures, intra-thoracic exudate or wall damage. Result of complete blood count revealed moderate anaemia with slight neutrophilic leukocytosis. Exploration of the swelling revealed a firm pseudo-encapsulated deep seated mass in the muscle beneath the sub-cutaneous tissue. The mass containing spongy blood clots. Cytology of the spongy tissue revealed numerous pleomorphic cells with high nucleicytoplasmic ratio. The nuclei were round elongated and oblong in shape with 2-3 nucleoli. In addition, histopathology showed variably sized, markedly  pleomorphic anaplastic cells with occasional strap cells which were   well-differentiated rhabdomyoblasts. There was lack of distinct cross-striation with multifocal areas of necrosis, hemorrhage and high mitotic index. The dog was treated with oral Cyclophosphamide, Ciprofloxacin and Prednisolone for two weeks. In conclusion, this case represents a rare cause of tissue swelling and should be differentiated from common causes of swelling in dogs such as haematoma and abscess.