When the muscles masquerade

A 61 year old African American gentleman presented with soreness in his thighs and shoulders and intermittent dark brown urine since two weeks. Review of systems revealed anorexia and weight loss of 20 pounds over the last two weeks. His past history was significant for hypertension, hyperlipidemia, diabetes mellitus and chronic smoking. There had been no recent change in his statin dosage. His exam revealed thigh and shoulder muscle tenderness and extensive clubbing of finger nails. His labs at admission were significant for Potassium (6.1), Phosphorus (5.2), ALT (223), AST (917), ALP (331), platelet count (681), CPK (36,317) units. His urine was positive for blood on dipstick. MRI of the upper extremities revealed extensive ischemic myositis of left shoulder and chest wall. Muscle biopsy reported the absence of inflammation and a possible neurological component. CT thorax and abdomen showed huge paratracheal mass, several lung nodules, mediastinal nodes and liver mass, suggestive of metastases. Bronchoscopy revealed non small cell lung cancer. Patient's hospital stay was complicated by superior vena cava syndrome, inpatient radiation therapy, brain metastases and outpatient chemotherapy. Thus although unique, malignancy should be considered in the differential for rhabdomyolysis, especially in the inpatient setting.