A 64-year-old woman was diagnosed with type 1 diabetes at the age of 52 years and treated with multiple daily insulin injections and acarbose. A fecal occult blood test at a checkup was positive, and colonoscopy was performed. A cystic submucosal tumor was found in the sigmoid colon, and biopsy was performed in the same area. Air bubbles were released during the biopsy, and as she was taking oral acarbose, she was diagnosed with pneumatosis cystoides intestinalis caused by α-glucosidase inhibitors and acarbose was discontinued. Colonoscopy performed 6 months later showed the disappearance of the submucosal tumor. Previous reports have shown that pneumatosis cystoides intestinalis caused by α-glucosidase inhibitors is often associated with respiratory diseases; however, there are also cases where it is discovered incidentally during colonoscopy or abdominal CT, as in this case. Pneumatosis cystoides intestinalis may sometimes show signs of free air and may be diagnosed as gastrointestinal perforation, resulting in emergency laparotomy; however, there are cases of drug-induced pneumatosis cystoides intestinalis that disappear when the causative drug is discontinued. Therefore, this disease should be kept in mind if signs of a cystic submucosal tumor are observed in patients taking α-glucosidase inhibitors.

A 72-year-old man was diagnosed with pancreatic cancer and multiple lung metastases at 70 years of age. Despite chemotherapy, the disease progressed. He subsequently underwent proton beam therapy at his own expense, which reduced both lesions. He developed anorexia and weight loss due to cancer cachexia, for which anamorelin hydrochloride was prescribed. At initiation, the patient had no history of diabetes mellitus or dexamethasone use. Three weeks later, hyperglycemic symptoms appeared. On day 41, the patient developed diabetic ketoacidosis (DKA), necessitating urgent hospitalization. After discontinuing anamorelin hydrochloride, his serum C-peptide levels increased, and eventually, his blood glucose levels were controlled without medication. To date, only two cases of DKA associated with anamorelin hydrochloride have been reported, both involved patients who were concurrently receiving antidiabetic medications and/or dexamethasone. In this case, neither of these contributing factors were present, suggesting that anamorelin hydrochloride alone may have contributed to the development of DKA. Clinicians should exercise caution when prescribing anamorelin hydrochloride to patients with malignancies, particularly pancreatic cancer.

The patient was a 49-year-old woman had no history of impaired glucose tolerance. She presented with cold sweats and dizziness consistent with hypoglycemia. During hypoglycemia, her immunoreactive insulin (IRI) levels were elevated to 22 μU/mL, and her C-peptide immunoreactivity (CPR) /IRI ratio showed minimal elevation, indicating impaired insulin clearance. The anti-insulin antibody-binding rate was 80.6 %. A Scatchard plot analysis showed R1 = 6.89 (10^-8 M) and K1 = 3.87 × 10^-2 (1/10^-8 M), indicating a high number of binding sites and low affinity, leading to a diagnosis of insulin autoimmune syndrome. The patient had HLA-DRB1*04: 03, and after discontinuing the glutathione-containing injection, which was considered to be a possible trigger, improvement of her symptoms, CPR/IRI ratio, antibody titers, and binding capacity were observed. Glutathione, which is widely used for cosmetic purposes, may contribute to the onset of insulin autoimmune syndrome and its use requires caution.