A 36-year-old woman presents to her primary care physician with lethargy and poor balance for about 4 months. She is a drummer in a traveling band and states that she has trouble performing due to lack of energy and difficulty coordinating her drum movements, as well as headaches and lightheadedness. She has a history of primary biliary cholangitis managed with ursodiol, and her mother is living with rheumatoid arthritis currently. She endorses a vegan diet and exercises regularly. She reports occasional marijuana use and denies any tobacco or alcohol use. Vital signs are within normal limits. Physical examination shows pale conjunctiva and an inflamed tongue. Neurologic examination reveals decreased limb proprioception and vibratory sensation. Laboratory studies reveal hemoglobin of 9.8 g/dL, a mean corpuscular volume (MCV) of 125 um3, and increased levels of methylmalonic acid. Based on these results, she is referred for an upper endoscopy, and histology of a biopsy from the stomach reveals diffuse atrophy of gastric body and fundus mucosa with intestinal metaplasia.
Based on the current diagnosis, the patient is at highest risk for which of the following conditions?
C) Gastric adenocarcinoma, intestinal type
This patient has evidence of chronic autoimmune gastritis. A personal and family history of autoimmune disease, macrocytic anemia, vegan diet, vibratory sensation impairment, and proprioceptive deficits should raise suspicion for vitamin B12 deficiency. Vitamin B12 deficiency is an important feature of chronic autoimmune gastritis because gastric parietal cells are being destroyed, releasing less intrinsic factor. Histology reveals diffuse gastric atrophy of the stomach body and fundus with intestinal metaplasia seen in autoimmune gastritis, which is a risk factor for gastric adenocarcinoma, intestinal type.
Answer choice A: Carcinoid tumor, is incorrect. Carcinoid tumors are neuroendocrine malignant tumor that can arise anywhere, but the small intestine is the most common site. If it metastasizes from the small intestine to the liver and into systemic circulation, carcinoid syndrome and carcinoid heart disease can result. Carcinoid syndrome presents with bronchospasm, diarrhea, skin flushing. Chronic autoimmune gastritis is not associated as a risk factor.
Answer choice B: Esophageal squamous cell carcinoma, is incorrect. Esophageal squamous cell carcinoma has many risk factors including alcohol and tobacco (avoided in this patient), very hot tea, achalasia, esophageal web, and esophageal injury. Chronic autoimmune gastritis is not associated as a risk factor.
Answer choice D: Mucoepidermoid carcinoma, is incorrect. Mucoepidermoid carcinoma is a malignant tumor made of mucinous and squamous cells in the salivary gland that could involve the facial nerve if invasive. It is not related to chronic autoimmune gastritis.
Answer choice E: Pancreatic adenocarcinoma, is incorrect. Pancreatic adenocarcinoma is more commonly seen in the elderly population, and the major risk factors include chronic pancreatitis and smoking.
Key Learning Point
Autoimmune gastritis is associated with autoantibodies against intrinsic factor and/or parietal cells. The destruction of parietal cells and intrinsic factor leads to vitamin B12 deficiency and pernicious anemia, which can present with proprioceptive and vibratory deficits, generalized weakness and lethargy, glossitis, and lightheadedness. Chronic autoimmune gastritis affects the body and fundus of stomach while sparing antrum but otherwise has a diffuse pattern with intestinal metaplasia. Patients with chronic autoimmune gastritis have an increased risk of developing gastric adenocarcinoma, intestinal type.
