Eosinophilic esophageal myositis mimicking achalasia: a rare case of dysphagia with extreme LES pressures and histologic clarity.

Eosinophilic infiltration of the esophageal muscular layer, known as eosinophilic esophageal myositis (EoEM), is an exceptionally rare condition that can mimic primary motility disorders such as achalasia. We present the case of a 72-year-old male with progressive dysphagia and significant weight loss, whose high-resolution manometry revealed findings consistent with achalasia, but with unusually elevated lower esophageal sphincter pressures. Surgical myotomy was performed and histopathological analysis unexpectedly revealed intense eosinophilic infiltration of the muscularis propria. The patient was treated with systemic corticosteroids, followed by topical budesonide, leading to partial and temporary clinical improvement. This case highlights eosinophilic esophageal myositis as a potential, but underrecognized differential diagnosis in patients with atypical achalasia features and treatment-refractory dysphagia.