EBV-positive mucocutaneous ulcer (EBVMCU) is an indolent, superficial lymphoproliferative disorder that occurs in either iatrogenic or age-associated immunocompromised patients with latent Epstein-Barr virus (EBV) infection. Although EBVMCU is histologically similar with other lymphoproliferative disorders, such as EBV-positive diffuse large B cell lymphoma, the diseases are classified as distinct entities by the World Health Organization with different clinical manifestations, prognosis, and genetic profiles. EBVMCU commonly shows spontaneous regression by conservative management, reduction or cessation of immunosuppressive treatment, but local progression is possible. Complete remission of disease can be achieved with combination of surgical resection, chemotherapy and local radiation therapy. Herein, we report 2 cases of oral superficial lymphoproliferative disorders arising adjacent to the gnathic bone with striking differences in prognosis and bone involvement. One of the cases induced extensive osteomyelitis in the underlying bone. Furthermore, we discussed the differential diagnosis of EBVMCU and reviewed the former literature.

Cordyceps species are known to produce numerous active components and are used for diverse medicinal purposes because of their varied physiological activities, including their anticancer, anti-inflammatory, and antimicrobial effects. Cordycepin, one of adenosine analogues, differs from adenosine in that its ribose lacks an oxygen atom at the 3' position. Cordycepin has been reported to be a main effector molecule in Cordyceps extracts that executes antiviral activities against several viruses including influenza virus, plant viruses, human immunodeficiency virus (HIV), murine leukemia virus, and Epstein-Barr virus (EBV). In addition, adenosine and its deaminase inhibitor showed strong antiviral potentials that were about 4,000 times more potent than the activity of the direct inhibitory effect by adenine arabinoside on Herpes simplex virus (HSV)-1, suggesting adenosine itself plays an important role to produce antiviral activities. In this study, we show that cordycepin and adenosine possess antiviral and antitumor activities against EBV and EBVassociated gastric carcinoma, respectively. Furthermore, we report epigenetic mechanisms used by cordycepin and adenosine to exert their antiviral and antitumor effects.

We report a double primary gastric cancer of different types seen on an endoscopy at the same time. At the first gastroscopy, Lymphoepithelioma-like carcinoma (LELC) appeared to be a benign submucosal tumor (SMT) and gastric adenocarcinoma was limited to the mucosa. Adenocarcinoma was removed by endoscopic submucosal dissection (ESD). However, a followup gastroscopy revealed an enlarged SMT, and another ESD was performed. The patient was additionally diagnosed with gastric LELC. This is the only case that LELC and gastric adenocarcinoma were found at the same time in Korea; therefore, the authors report this case with literature review.