Gastrointestinal Malakoplakia: Clinicopathologic Analysis of 26 Cases. Am J Surg Pathol 2020 Sep;44(9):1251-1258
Date
04/18/2020Pubmed ID
32301754DOI
10.1097/PAS.0000000000001491Scopus ID
2-s2.0-85084236096 (requires institutional sign-in at Scopus site) 11 CitationsAbstract
Malakoplakia is an inflammatory process related to defective macrophage response to bacterial infection. To further characterize the clinicopathologic manifestations of gastrointestinal malakoplakia, 26 cases were identified from 6 institutions. Hematoxylin and eosin-stained slides and available stains were reviewed, and pertinent clinicopathologic features analyzed. Sixteen patients were women (62%). Mean patient age was 64 (range: 24 to 83). Sites included the colorectum (n=23), appendix (n=1), and stomach (n=2). Clinical indications for tissue procurement included screening (n=14), tumor resection (n=5), diarrhea (n=1), adenoma surveillance (n=1), ulcerative colitis flare (n=1), abdominal pain (n=1), and appendicitis (1). All cases featured histiocytes with abundant, pale, eosinophilic cytoplasm focally containing Michaelis-Gutmann bodies. The process frequently involved the mucosa (n=19), with architectural distortion in 13 cases. Lymphoid aggregates were present in 18 cases, which were prominent or obscuring in 11 (all colon biopsies) and provoked concern for lymphoma in 2. Associated findings included adenocarcinoma (n=5), adenoma (n=2), gastric hyperplastic polyps (n=1), chemical gastritis (n=1), collagenous colitis (n=1), and active chronic colitis (n=2). In cases with available stains, Michaelis-Gutman bodies were highlighted by Periodic Acid-Schiff with diastase, Von Kossa, and iron stains. Although 2 cases were positive for Tropheryma whipplei antibody, no T. whipplei transcripts were detected on real-time polymerase chain reaction. All patients with available follow-up are alive and well with no additional instances of malakoplakia. Malakoplakia of the gastrointestinal tract is a benign, incidental finding. Although histologic features in the stomach and colon resections are similar to those at other sites, exuberant lymphocytic response in colon biopsies and immunoreactivity with T. whippleii antibody may provoke initial confusion and lead to unnecessary time and resource investment.
Author List
Zhang Y, Byrnes K, Lam-Himlin D, Pittman M, Pezhouh M, Gonzalez RS, Alruwaii Z, Larman T, Miller JA, Matoso A, Oshima K, Epstein JI, Montgomery EA, Voltaggio LAuthor
James Adam Miller MD, MPH Assistant Professor in the Pathology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AdultAged
Aged, 80 and over
Biopsy
Female
Gastric Mucosa
Gastrointestinal Diseases
Gastrointestinal Tract
Humans
Incidental Findings
Intestinal Mucosa
Malacoplakia
Male
Middle Aged
Prognosis
Tropheryma
United States
Young Adult