Herpes Simplex Virus Pseudotumor Masking as Gastric Malignancy.

Herpes simplex virus (HSV) pseudotumor is a rare presentation of HSV and has not been previously reported in the stomach. A 51-year-old man with a medical history of HIV presented with new-onset dysphagia. Endoscopy revealed an HSV-positive mass at the gastroesophageal junction. After antiviral treatment, the patient returned with a 100-pound unintentional weight loss. Computed tomography showed an infiltrative mass with enlarged lymph nodes. The mass had progressed despite HSV treatment, and a repeat set of biopsies were negative for HSV with cells concerning for B-cell lymphoma. The patient was taken to the operating room for a full-thickness biopsy because of increasing concern for malignancy. The procedure was complicated by gastric perforation, leading to a total gastrectomy. Final pathology demonstrated an HSV-positive pseudotumor, negative for malignancy. It is important to diagnose gastric masses, especially in HIV-positive patients at high risk of infection and malignancy. However, immunocompromised patients with an HSV-positive mass should be treated for HSV pseudotumor with a longer than standard duration of antiviral therapy.