Lymphoepithelioma-like Carcinomas of the Stomach Report of 4 cases associated with Epstein-Barr virus

ABSTRACT

Lymphoepithelioma-like carcinoma (LELC) that histologically resembles nasopharyngeal lymphoepithelioma has been reported in various sites including the stomach, salivary gland, lung, skin, thymus, tonsil and uterine cervix. LELC of the stomach was rarely reported after the first report by Burke et al. in 1990. More than 60% of them were associated with Epstein-Barr virus (EBV). Most commonly affecting elderly Asians with slight male predominance (M/F ; 1.2/1), it usually is located in the proximal portion of the stomach and distinguished from lymphoid-rich adenocarcinoma by the absence of definitive glandular differentiation in the LELC. We recently experienced 4 cases of LELC of the stomach associated with EBV. Patients consisted of two Korean females and two Korean males with one in 3rd decade, one in 5th decade and two in 6th decade. The tumors of all cases were located in the proximal portion of the stomach. Gross types were 1 Borrman type I, 2 Borrman type II and 1 early gastric carcinoma type IIc. The size of the tumors varied from 0.8 cm to 7 cm. Microscopic findings were similar in all 4 tumors.; The tumors were composed of syncytial nests of undifferentiated cells having vesicular nuclei with prominent nucleoli, admixed with abundant lymphoplasma cell infiltration in the stroma. Immunohistochemical staining revealed that the tumor cells were reactive for cytokeratin and the stromal lymphocytes were mostly T cells. There were dark hybridization signals in the nuclei of most of the tumor cells but no signals in the stromal lymphocytes in three cases on in situ PCR hybridization and on all cases PCR amplification for EBNA-1. It is concluded that LELCs of the stomach have distinctive histologic characteristics and the usual association with EBV. Further accumulation of these cases will define the prognosis.