Macrophage aggregates in cytomegalovirus esophagitis

Cytomegalovirus (CMV) esophagitis may be difficult to identify in small endoscopic biopsy specimens, because diagnostic CMV inclusions may be absent or hard to find. The author has noticed aggregates of macrophages in the granulation tissue and exudates of esophageal ulcers with CMV inclusions and postulated that this may be a characteristic inflammatory response to the virus, similar to that seen in herpes simplex virus (HSV) esophagitis. To test this hypothesis, 14 esophageal biopsy specimens diagnosed with CMV infection at the University of Michigan over the last 10 years were analyzed for the amount and distribution of macrophage aggregates. Twelve of 14 biopsies showed aggregates of macrophages; five had patchy aggregates of macrophages in exudates, four had a perivascular distribution of macrophages present in granulation tissue, and three had macrophages present in both exudates and granulation tissue. The number of macrophages in CMV esophagitis was generally less than in HSV esophagitis, whereas the perivascular distribution of macrophages in granulation tissue was unique to CMV esophagitis. These findings indicate that aggregates of macrophages are a characteristic of CMV esophagitis as well as of HSV esophagitis and their presence in a biopsy specimen that does not show diagnostic viral inclusions warrants further study to identify CMV or HSV.