Epstein–Barr virus-associated gastric adenosquamous carcinoma with concurrent gastric carcinoma with lymphoid stroma: a case report and review of the literature

Abstract

Background Adenosquamous carcinoma (ASC)with concurrent gastric carcinoma with lymphoid stroma (GCLS) are extremely rare tumors. There are only limited cases reported in the literature. Epstein–Barr virus (EBV) infection was found in the concomitant GCLS, but none in the ASC. Here, we report the first case of gastric cancer with EBV infection detected in both ASC and GCLS. Case presentation A 59-year-old man complained of intermittent upper abdominal pain. The gastric endoscopy revealed a type IIc tumor located in the gastric body near the fundus of the stomach. Histological examination of the gastric tumor showed the coexistence of ASC and GCLS. Both components were positive for EBV-encoded RNA (EBER) in situ hybridization. Neoplastic nests of the former were positive for p63, p40 and CK5/6. The glandular components showed positive acid mucus in the Alcian-blue periodic-acid-schiff (AB-PAS) staining. There was significant difference in the expression of epidermal growth factor receptor (EGFR) between adenocarcinoma and squamous carcinoma, but not in other proteins such as human epidermal growth factor receptor 2 (HER2), p53 and mismatch repair proteins. The role of EGFR signaling pathway needs to be further explored in the differentiation of squamous carcinoma in the gastric ASC. Finally, a diagnosis of early EBV associated gastric ASC with concurrent GCLS (pT1bN1) was made. The patient took a single-drug S1 periodically for half a year after the surgery and has been disease free during 8 months of medical follow-up. Conclusions This is the first case of EBV associated gastric ASC with concurrent GCLS, and pathologists and clinicians should recognize and pay attention to this type of tumor.

Case report: Gastric adenosquamous carcinoma with EBV-positive component of squamous cell carcinoma mixed with gastric carcinoma with lymphoid stroma: A novel case report and literature review

“…Lymph node metastases from all three components were observed, with AC being the most common component. In the reported cases, EBER staining was only positive in the GCLS region in three cases ( 1 - 3 ), while it was throughout positive in one case ( 4 ). In the Ji-Hoon’s report ( 5 ), EBER staining was diffusely positive in GCLS and focally positive in SCC.…”

“…In one case ( 5 ), PD-L1 was focally expressed in approximately 5% of SCC cells. And in another case ( 4 ), combined positive score for PD-L1 expression was 15, mainly positive expression on lymphocytes. However, PD-L1 expression was negative in the present case.…”

“…The other was AC differentiated into two forms: one showed differentiation toward EBV-related tumors and the other demonstrated squamous differentiation. A mixture of AC and SCC can be seen in four cases, and even a transition of AC and SCC has been observed ( 4 ). In addition, AC is the most common component of the metastatic lymph nodes of patients with gastric ASC ( 3 , 4 , 13 ).…”

“…A mixture of AC and SCC can be seen in four cases, and even a transition of AC and SCC has been observed ( 4 ). In addition, AC is the most common component of the metastatic lymph nodes of patients with gastric ASC ( 3 , 4 , 13 ). In the present case, considering the presence of a transition area between AC and the other two components with EBER positive expression, we suggest the second possibility.…”

“…GASC mixed with GCLS associated with EBV infection is extremely rare. Only four cases ( 1 – 4 ) of adenosquamous carcinoma (ASC) associated with EBV have been reported so far, including three cases of GASC associated with GCLS in which EBER staining was positive only in the GCLS region and another case in which EBER staining was positive throughout all components. Besides, one study showed that EBV infection was detected in the SCC component of GCLS with focal SCC differentiation ( 5 ).…”