Colonic Epstein-Barr virus mucocutaneous ulcer mimicking metastatic cancer: a diagnostic pitfall on PET/CT in immunosuppressed patients.

Epstein-Barr Virus-positive mucocutaneous ulcers (EBVMCU) are a rare disease entity that causes mucocutaneous ulcerations in the gastrointestinal tract, oropharynx, and skin. Typically associated with immunosuppressed patients, individuals may present with nonspecific symptoms and scan findings similar to those of malignancies. Treatment usually responds favourably to conservative management or withdrawal of immunosuppression, although rarely patients require more aggressive therapies including surgery, immuno-, chemo-, or radio-therapy. We encountered an unusual case of a patient with EBVMCU who presented with cough, dysphagia, and weight loss. Imaging features on [18F]-FDG PET/CT as well as initial biopsy results were nonspecific. The colonoscopic features were highly concerning for malignancy, with the diagnosis only finally being confirmed following surgical resection. To our knowledge, this is the first case report to describe the FDG PET/CT findings of EBVMCU within the bowel, and readers should consider this as a differential to avoid potential misdiagnosis and unnecessary intervention.