アカラシアを偽装した転移性小葉乳がん

A 64-year-old woman with stage IV breast cancer taking exemestane presented with weight loss of 10 to 15 pounds and dysphagia of 3 to 6 months in duration. Upper endoscopy and positron emission tomography/computed tomography did not reveal a pathologic diagnosis. Esophageal manometry was suggestive of achalasia. The patient was referred for an esophageal peroral endoscopic myotomy (E-POEM) procedure. We aim to describe a rare finding encountered during submucosal dissection in an E-POEM that may result in an incomplete, aborted, technically challenging, or ineffective procedure.

An E-POEM using a posterior approach is our preferred method. E-POEM was planned in the standard fashion. A mucosotomy followed by submucosal injection and dissection was performed, with plan for an extended circular and full-thickness myotomy of the lower esophageal sphincter.

During submucosal dissection, atypical yellow-brown tissue was encountered within the submucosal tunnel. This was initially thought to be related to fibrosis from severe achalasia. In total, 3 tunnels were created with eventual abortion of the procedure because this abnormal tissue was found 3 to 4 cm proximal to the esophagogastric junction in each tunnel. This tissue was biopsied, and all tunnels were closed without any postprocedural adverse event. Pathology demonstrated metastatic lobular breast cancer.

Invasive lobular breast cancer has a propensity to spread to the GI tract as compared with other forms of cancer such as invasive ductal carcinoma. Endoscopists who perform E-POEM who encounter difficulty expanding the submucosal plane during E-POEM should keep malignancy and metastatic disease in mind as a rare cause of pseudoachalasia, even in the absence of nondiagnostic pre-peroral endoscopic myotomy evaluation.