“Playing detective” in a case of paraneoplastic polymyositis

Abstract

Adult-onset polymyositis (PM) belongs to the idiopathic inflammatory myopathy (IIM) group and manifests with proximal muscle weakness, elevated muscle enzymes and positive myositis- specific antibodies. The subset of autoantibodies can indicate a higher risk for cancer association. An 82-year-old diabetic patient, with multiple cardio-vascular comorbidities, was hospitalized for muscle weakness of the upper girdle, dysphagia and dysphonia, accompanied by elevated serum muscle enzymes. Muscle biopsy showed an inflammatory infiltrate while immunological assays found positive ANA and anti-NXP2 antibodies. The diagnosis of PM was established, thus a screening for underlying neoplasia was required. Upper endoscopy visualized an area of ectopic mucosa in the esophagogastric junction and the biopsy confirmed a squamous cell carcinoma in situ. Patient had favorable muscle outcome under methylprednisolone pulse therapy. It is worth noting that polymyositis is more rarely associated with cancers as compared to dermatomyositis (DM). In conclusion, the type of antibodies identified in myositis can represent an alarm signal for oncologic screening, making possible an early diagnosis and efficient treatment of a hidden tumor.