Background <p>Idiopathic sensory ganglionopathy is characterized by dorsal root ganglion dysfunction, while achalasia is an esophageal motility disorder marked by impaired relaxation of the lower esophageal sphincter. Although both may have immune-mediated components, their concurrent presentation without other autoimmune comorbidities is exceedingly rare.</p> Case presentation <p>We describe a 44-year-old Thai male who presented with progressive sensory disturbances and dysphagia. Neurological evaluations confirmed idiopathic sensory ganglionopathy, while esophageal manometry identified achalasia type II. The patient initially received high-dose steroids but developed steroid-induced Cushing syndrome, prompting a switch to intravenous immunoglobulin therapy, which improved the sensory symptoms but did not alleviate the dysphagia. Ultimately, pneumatic dilation fully resolved his achalasia-related swallowing difficulties.</p> Conclusion <p>This case underscores a possible overlapping autoimmune pathogenesis for idiopathic sensory ganglionopathy and achalasia, even in the absence of other known autoimmune disorders. The contrasting responses to immunotherapy highlight the complexity of treating coexisting conditions with distinct disease mechanisms. Further research into shared immunologic pathways may advance our understanding of these rare but notable disorders.</p>