In the present study, a 12 years old male Anatolian Shepherd dog referring to Erciyes University, Clinics of Veterinary Medicine and suffering from emaciation, dullness and scratching his back was reported. Clinical examination revealed that there was a haemorrhagic, ulcerative and necrotic mass at the base of its tail. The tail beginning from the 5th coccygeal vertebrae was amputated since no improvement was obtained by medical treatment. Latero-lateral radiographic examination showed a mass formation as much as a size of a walnut located on the left basis of the heart. On haematology, the level of the total erythrocytes haemoglobin and haematocrit values were found to be low, whereas leucocytes value was found high. Histopathological examinations of the mass obtained by surgery revealed squamous and basal cell carcinoma originating from epidermis; osteosarcom originating from dermis. The case was generalized as carcinosarcom. The animal was monitored up to 6 months postoperatively during which no improvement was recorded considering clinical, haematological and radiographic findings. At the end of this period, the masses were found to be enlarged and increased in numbers on lateral thoracic radiography. Therefore, the dog was euthanatized. The radiographic findings were consistent with necropsy assessment. In the lung masses, metastatic foci, associated with the tumours originating from the coccygeal vertebrae and diagnosed as carcinosarcom were determined.