Urinary Bladder - Infiltration Cellular, Lymphocyte
Infiltration cellular, lymphocyte, usually involves a focal to multifocal, well-defined, suburothelial infiltration of predominantly lymphocytes (Figure 1 and Figure 2). Infiltrates can also be seen around vessels. Most cellular infiltrates tend to be spontaneous, in an otherwise normal bladder, and with little or no pathologic significance.
Since smaller infiltrates are common in rodent bladders, it is not uncommon for pathologists to have a diagnostic threshold for diagnosing these infiltrates. It is the responsibility of the pathologist to determine the threshold and to consistently maintain that threshold throughout the study. When diagnosed, lymphoid infiltrates should be given a severity score.
Frazier KS, Seely JC, Hard GC, Betton G, Burnett R, Nakatsuji S, Nishikawa A, Durchfeld-Meyer B, Bube A. 2012. Proliferative and non-proliferative lesions in the rat and mouse urinary system. Toxicol Pathol 40:14S-86S.Abstract: http://www.ncbi.nlm.nih.gov/pubmed/22637735