Low-grade myofibroblastic sarcoma of gastric cardia on (18)F-FDG positron emission tomography/computed tomography: An extremely rare case report

RATIONALE: Low-grade myofibroblastic sarcoma (LGMS) is a rare mesenchyme-derived tumor, which usually occurs in head, neck (especially tongue and mouth), and limbs. In this report, we described a case of gastric LGMS by (18)F-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography/computed tomography (PET/CT), which has not been reported previously. PATIENT CONCERNS: A 51-year-old female patient was admitted to our hospital with upper abdominal discomfort for 1 year and gradually increased eating difficulties over the last 3 months. From gastroscopy, an ulcer of 1.0 cm × 1.2 cm at the entrance of cardia and stiffness of peripheral mucosa were found, leading to suspicion of cardia cancer. (18)F-FDG PET/CT was performed for further diagnosis and staging. DIAGNOSES: According to pathological findings in combination with immunohistochemical features, diagnosis of gastric LGMS was made. INTERVENTIONS: To relieve symptoms of upper gastrointestinal obstruction in the patient, proximal gastrectomy was carried out 1 week after the (18)F-FDG PET/CT scan. OUTCOMES: The patient died due to advanced tumor. LESSONS: (18)F-FDG PET/CT scan showed local thickening of the gastric wall, invasion of adjacent soft tissue, diaphragmatic and peritoneal metastasis at early stage, absence of regional lymph node metastasis, and increased (18)F-FDG metabolism in primary tumor and metastatic tumor.