Thymoma-Associated Paraneoplastic Syndromes: Concurrent Inflammatory Myopathy and Guillain–Barré Syndrome Complicated by Reverse Takotsubo Cardiomyopathy

Background: Thymoma is associated with a range of paraneoplastic and immune-mediated conditions, most commonly myasthenia gravis and less frequently inflammatory myopathy or Guillain-Barré Syndrome (GBS). The co-occurrence of GBS and inflammatory myopathy in the setting of thymoma is extremely rare. Additionally, reverse Takotsubo cardiomyopathy, a stress-induced cardiac dysfunction, has not been reported in association with this combination. Case presentation: We report a 48-year-old Indian male who presented with subacute proximal limb weakness, followed by acute ascending paralysis. Investigations revealed elevated muscle enzymes, MRI features of myositis, and nerve conduction studies suggestive of the Acute Motor and Sensory Axonal Neuropathy (AMSAN) variant of GBS. Cerebrospinal Fluid (CSF) analysis showed albumin-cytologic dissociation, and muscle biopsy was suggestive of inflammatory myopathy. Imaging identified an anterior mediastinal mass, confirmed as Type A thymoma. The patient also developed chest pain, with elevated troponin levels and echocardiographic findings consistent with reverse Takotsubo cardiomyopathy, despite normal coronary angiography. He was treated with high-dose corticosteroids and plasmapheresis, followed by immunosuppressive therapy, resulting in gradual neurological improvement. Conclusion: This case discusses a rare combination of GBS, inflammatory myopathy, and thymoma, complicated by reverse Takotsubo cardiomyopathy in the absence of myasthenia gravis, and highlights the importance of evaluating for paraneoplastic etiologies in atypical neuromuscular presentations.