Low-grade myofibroblastic sarcoma of gastric cardia on 18F-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 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. 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 F-FDG PET/CT scan.

Outcomes: The patient died due to advanced tumor.

Lessons: 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 F-FDG metabolism in primary tumor and metastatic tumor.