To explore the clinicopathological features and CT imaging features of primary gastric lymphoepithelioma-like carcinoma(LELC)in order to improve the understanding of the disease.

The clinical, pathological and CT imaging data of 20 patients with gastric LELC confirmed by surgery and pathology admitted to the First Affiliated Hospital of Zhengzhou University from February 2016 to June 2021 were retrospectively analyzed.There were 16 males and 4 females.They ranged in age from 31 to 76 years, with a median age of 58 years.All patients underwent CT plain and enhanced examinations, and two experienced abdominal radiologists observed and analyzed the imaging data, including lesion location, morphology, growth pattern, ratio of length-diameter to thick-diameter, density, presence of ulcers on the mucosal surface, and enhancement pattern and degree of lesions.All specimens were diagnosed by HE staining and immunohistochemical staining.

Gastric LELC was located in the gastric body in 9 cases, cardia-fundus in 8 cases, and gastric sinus in 3 cases.The length-diameter of the lesions ranged from 1.5 to 8.3 cm, with a mean of(4.1±1.9)cm, the thick-diameter of the lesions ranged from 1.0 to 7.0 cm, with a mean of(3.2±1.6)cm, and the ratio of thickness to length-diameter ranged from 0.33 to 1.00(0.79±0.17). Nine cases showed a limited mass in the gastric wall, 4 cases showed centripetal thickening of the gastric wall, 4 cases showed a submucosal mass, and 3 cases showed a diffuse mass in the gastric wall; 13 cases showed ulceration on the surface of the lesion, and only 1 case showed necrosis within the lesion.CT values ranged from 31 to 57(42.53±7.54)HU on plain CT, 59 to 118(87.00±18.64)HU on arterial CT, and 50 to 123(91.57±17.72)HU on venous CT.After enhancement, 14 cases had uniform enhancement and 6 cases had uneven enhancement; 16 cases showed persistent enhancement and 4 cases showed progressive enhancement, of which 11 cases had significant enhancement.Pathology showed that 14 cases were ulcer type and 6 cases were protuberant type.There were 7 cases of vascular tumor thrombus and 12 cases of nerve invasion; 7 cases invaded the subserous layer, 5 cases invaded the muscular layer, 5 cases invaded the full layer of gastric wall, 2 cases invaded the serous layer and 1 case invaded the submucosa.Twenty cases were positive for EBER expression by in situ hybridization.

Gastric LELC usually occurs in the proximal stomach of middle-aged and elderly men.The morphology on CT is diverse, and it can also be shown as a submucosal mass.The density of the focus is uniform, and necrosis is not easy to occur.Most of the enhancement shows significantly persistent enhancement.The diagnosis depends on histopathology and immunohistochemistry.The clinical stage is early when the diagnosis is made, lymph node involvement is rare, and the prognosis is good.