Necrotizing myopathy as paraneoplastic disorder in tonsillar squamous cell carcinoma

Abstract

Introduction: Myositis including polymyositis and dermatomyositis has been reported in different types of cancer mainly lung, breast and ovarian cancer. Case Report: We report a case of necrotizing myopathy presenting in a 59-year-old patient after a recent diagnoses of squamous cell carcinoma of the tonsil. Three weeks later, the patient was admitted for worsening generalized weakness, dysphagia and constipation. Patient was bed bound requiring full assistance. Physical examination was significant for symmetrical weakness in his proximal muscle groups of upper and lower extremity. Creatinine kinase (CK) was 13,000 U/L with markedly elevated liver enzymes. EMG showed myotonia in all muscle groups with more prominence in axial and proximal muscles than distal. Following the biopsy of biceps muscle, IV steroid was initiated. IVIG was started later in addition to oral steroids due to suboptimal response. In the interim, biopsy showed severe necrotizing myopathy. Myositis Ab panel and paraneoplastic antibody panel including voltage gated potassium channel (VGPC) Ab, ANNA-1, ANNA-2 and PCA-1 Abs were negative. CK trended down to 1196 U/L after three weeks of steroids with moderate improvement in the muscle weakness. Conclusion: Necrotizing myopathy can be associated with squamous cell carcinoma of tonsil. Serology may be negative and the presence of diffuse myotonia suggests myopathy. However, biopsy shows myofibers undergoing myophagocytosis with minimal inflammatory cells thus confirming necrotizing myopathy.