[A Case of Gastric Adenosquamous Cell Carcinoma That Produces G-CSF].

Gastric adenosquamous cell carcinoma is relatively rare. We report a case of adenosquamous cell carcinoma and a carcinoma producing granulocyte-colony stimulating factor(G-CSF). An 85-year-old man was admitted to our department in 20XX with complaints of anemia and anorexia. Computed tomograph(y CT)showed a rapidly growing mass within 1 month. Based on gastrointestinal endoscopy and elevated tumor markers, the patient was diagnosed with advanced gastric cancer and underwent distal gastrectomy. A biopsy revealed mixed pathological features of adenocarcinoma and squamous cell carcinoma components, leading to a final diagnosis of gastric adenosquamous cell carcinoma. The patient also had preoperative leukocytosis, which immediately improved after surgery, and the pathology was positive for G-CSF staining, leading to the conclusion of a G-CSF-producing tumor. The patient had recurrence at 5 months postoperatively and a palliative treatment plan was initiated. These findings suggest that adenosquamous carcinoma of the stomach and G-CSF-producing tumors may exhibit aggressive behavior and that they should be considered in the differential diagnosis of unexplained leukocytosis.