The First Reported Case of Peroral Endoscopic Myotomy in a Child in Portugal.

Introduction: Achalasia is a rare disorder, with few cases occurring during childhood. It is also part of the Allgrove syndrome phenotype and a clinical feature that has a major impact on children's development. Timely diagnosis and effective treatment of symptoms are essential. The novel peroral endoscopic myotomy (POEM) may represent an effective alternative in children. Case Presentation: We present the case of a female child born in 2013, without relevant family history or perinatal events. At 6 years old, she presented with seizures related to recurrent hypoglycemia episodes, and adrenal insufficiency was diagnosed. Two years later, the patient was referred to our institution due to regurgitation and vomiting, causing failure to thrive. After an upper endoscopy with no significant findings, high-resolution manometry revealed type II achalasia. Alacrima was also part of the clinical picture, and Allgrove syndrome was genetically confirmed. Due to significant symptoms, an endoscopic pneumatic dilation was performed, with transient relief of symptoms. After a second pneumatic dilation and several hospitalizations due to achalasia complications, a POEM was considered. She underwent POEM in March 2024, without adverse events and excellent short-term outcomes. Discussion: Although there is limited literature on POEM in children, the results demonstrate an encouraging success rate, compared to pneumatic dilation and laparoscopic Heller's myotomy. We present the first reported case of POEM performed in a child in Portugal. The long-term efficacy of this promising minimally invasive procedure should be assessed in the pediatric population.