A 77-year-old man with no history of interest. He consulted for reddening of the skin in the upper third of the chest and proximal part of both limbs together with proximal muscle weakness in the arms and legs, heliotrope erythema on the eyelids and purplish papules on the knuckles of both hands, of one month's evolution. Laboratory tests showed creatinkinase 736 IU, LDH 545 IU, urea 63 mg/dl, CA 19.9 64.1 U/ml. Electromyogram: findings compatible with inflammatory myopathic process. Muscle biopsy: inflammatory changes compatible with dermatomyositis. With the diagnosis of dermatomyositis, treatment was started with prednisone 60 mg/day and study: thoracoabdominal CT scan: 6 cm pancreatic mass and hypodense hepatic lesions. Hepatic puncture-biopsy: Adenocarcinoma. Referred to Oncology. After 8 weeks of corticoids, with no improvement in the skin lesions or muscle weakness, and in view of the diagnosis of stage IVB pancreatic adenocarcinoma due to liver metastases, we started treatment with gemcitabine 1250 mg/m2 on days 1 and 8 every 21 days. After 2 cycles of treatment, complete resolution of the skin lesions, normalisation of muscle enzymes and recovery of strength were documented. Currently the patient remains asymptomatic after 6 cycles of treatment and with less than 50% response to his baseline disease.