Which is the BEST site for taking biopsy in a case of viral oesophagitis?

The best place to take biopsy is from within the the squamous mucosa at the edges of the ulcer and in sloughed cells within the exudate. HSV esophagitis: Esophagus is the most common site of GI herpes infection. HSV infection is commonly seen in immunocompromised patients, including those with underlying lymphoma, leukemia and AIDS, transplant recipients and burn victims. It commonly involves the middle and distal thirds of the esophagus. Microscopically, the characteristic feature of herpetic infection occur in the squamous epithelium at the margin of the ulcers or erosions. The 2 types of viral inclusions present in HSV infection are: homogenous or smudge cells and acidophilic inclusions with a surrounding clear halo and peripheral chromatin migration(Cowdry type A). Ref: Morson and Dawson's Gastrointestinal Pathology edited by Neil A. Shepherd, page 27.