Lymphoepithelioma-like Carcinoma: Case of a Rare Gastric Cancer

Abstract

An elderly female underwent outpatient EGD for a long history of RUQ pain. She had a history of GERD and prior cholecystectomy. A 2cm pedunculated polyp was noted in the gastric body and snare polypectomy was performed. Histological examination demonstrated small nests and chords of tumor cells separated by dense inflammatory infiltrate predominantly composed of lymphocytes and neutrophils. The malignant cells had invaded the submucosa extending into the cauterized margin of resection. Immunohistochemistry staining for expression of cytokeratin was positive. In situ hybridization for Epstein-Barr virus-encoded small RNAs (EBER) showed intensive nuclear hybridization signal within the tumor cells. Final pathological diagnosis was poorly differentiated EBV associated lymphoepithelioma-like gastric carcinoma (LELC) with submucosal invasion. CT of chest, abdomen and pelvis demonstrated no new enlarged lymph nodes or masses. The patient agreed for follow up surveillance with plans to repeat upper endoscopy in 3 months. LELC is a rare subtype of gastric neoplasm comprising approximately 1-4% of all gastric cancers (GCs). They are characterized histologically by dense stromal lymphocyctic infiltrate with small nests of tumor cells. More than 80% are associated with EBV. Typically these tumors occur in elderly males and are usually located in the cardia or body of the stomach. They can present as projecting masses, mucosal thickening or submucosal mass with or without ulceration. Generally they tend to have a better prognosis when compared to other GCs, especially when associated with EBV, as demonstrated by lower propensity for lymph node invasion as well as longer overall survival and disease survival. It is postulated that this favorable prognosis stems from the immunological response to EBV proteins expressed on the tumor cells. A recent case series highlighted endoscopic submucosal dissection (ESD) along with medical follow up as being an adequate conservative approach compared to historic radical gastrectomy for patients with early EBV associated LELC despite submucosal invasion of greater than 500μm. In conclusion, clinicians should be aware of this rare variant of GC and recognize its distinct clinicopathological features. They have a more favorable prognosis compared to other GCs and EBV is present in the majority of cases. Endoscopic resection is recommended for diagnosis and can be potentially curative even in cases of deep submucosal invasion.Figure 1Figure 2