Analysis of Missed Diagnosis of Gastric Lipomas by CT

Introduction: Although Computed Tomography (CT) is the most convenient technology for the diagnosis of gastric lipoma, it also has a high rate of missed diagnosis of gastric lipoma.

Objective: To analyze the causes of missed diagnosis of gastric lipomas by CT.

Methods: We retrospectively studied the CT images and CT diagnosis reports of 25 cases of gastric lipoma confirmed by surgery or clinical follow-up at the Affiliated Hospital of North Sichuan Medical College and Nanchong Central Hospital from 2016 to 2020 and analyzed the causes of missed diagnosis of gastric lipomas.

Results: Among the 25 cases of gastric lipomas included in this study, 17 cases (68.0%) were correctly diagnosed by CT, and 8 cases (32.0%) were missed, but there was no case of misdiagnosis. Eighteen cases (72.0%) of gastric lipomas were located in the gastric antrum, 2 cases (8.0%) at the junction of the gastric body and antrum, 5 cases (20.0%) at the fundus of the stomach, 23 cases (92.0%) under the gastric mucosa, and 2 cases (8.0%) under the gastric serous membrane. All gastric lipoma cases were manifested as round or oval-shaped low-density shadows with clear boundaries on CT. 22 cases (88.0%) showed homogeneous low-density shadows while 3 cases (12.0%) mainly showed low-density shadows containing medium-density strips. There was no obvious enhancement in the contrast-enhanced CT scan. The gastric lipoma cases missed by CT were all located under the gastric mucosa of the gastric antrum. When reading the CT images on the default upper abdominal window width and window level, all the missed lesions were similar to the gas image. And the straight meridian of the three lesions was less than 2 cm.

Conclusion: Fat density shadow in gastric antrum area was mistaken for gastrointestinal gas. Improper CT image window width and window levels and small gastric lipoma volume, along with insufficient knowledge of gastric lipomas imaging by the clinician, might be the main causes of missed diagnosis of gastric lipomas by CT. Familiarity with the CT manifestations of gastric lipomas and rich clinical experience can improve the rate of correct diagnosis of gastric lipomas by CT.