Osteogenesis imperfecta, pseudoachalasia, and gastric cancer.

Osteogenesis imperfecta (OI) is a rare, inherited skeletal disorder characterized by abnormalities of type 1 collagen. Malignancy is rarely reported in patients with OI and it was suggested that this disease can protect against cancer. Here, we report a 41-year-old woman with symptoms of achalasia where repeated treatment of pneumatic dilation and stent replacement was unsuccessful; therefore, surgery was performed. Pathology showed gastric adenocarcinoma unexpectedly. Chemotherapy was given after assessing dihydropyrimidine dehydrogenase (DPD) enzyme activity, which can be deficient in OI patients. This is the first report of gastric cancer mimicking achalasia in a patient with OI.