Diagnostic Overlap Between Eosinophilic Esophagitis and Achalasia in a Young Adult.

Eosinophilic esophagitis (EoE) and achalasia share overlapping clinical and histologic features, creating diagnostic ambiguity. We describe a late-adolescent male patient with progressive dysphagia and esophageal eosinophilia who was initially treated for EoE without symptomatic improvement despite histologic remission. High-resolution esophageal manometry (HREM) and functional lumen imaging probe testing (EndoFLIP) findings were consistent with type II achalasia. The patient chose to undergo a per-oral endoscopic myotomy (POEM) with symptomatic resolution, supporting achalasia as the primary diagnosis. This case highlights the importance of esophageal motility testing and patient-centered discussions on therapeutic options when dysphagia persists despite treatment of EoE.