Crypt Abscess

I write in regard to a recent article titled “Histologic Lesions Induced by Murine Norovirus Infection in Laboratory Mice” by Hsu et al. ¹ Their figures 7 and 8 are said to contain lymphohistiocytic colitis with “crypt abscess.” The arrows indicate what the authors have called a “crypt abscess.” I write to suggest that the dilated colonic crypt is not a crypt abscess at all; it is instead a cystically dilated crypt with attenuated epithelium, containing necrotic epithelial cells, fragments of pyknotic nuclei, and strands of mucus. Among the cells of the crypt, there are perhaps 3 or 4 granulocytes. Bona fide crypt abscesses are filled with neutrophils, some dead, some alive. The authors are referred to the ulcerative colitis literature, figure 35-11 and figure 35-12 in Clinical Gastroenterology, ⁴ figure 17-47 in Robbins and Cotran Pathologic Basis of Disease, ² and figure 11-134 in Ackerman’s Surgical Pathology. ³ Cystically dilated crypts occur infrequently in a number of species, sometimes in association with mucosal inflammation. In this time of “one medicine,” it behooves us to provide descriptions consistent with those in the human medical field.

H. J. Van Kruiningen, DVM, PhD, MD Department of Pathobiology and Veterinary Science, University of Connecticut, Storrs, CT, USA