Atypical Forms of Microscopic Colitis: Morphological Features and Review of the Literature

Abstract

Microscopic colitis is defined as a syndrome of chronic watery diarrhea with a chronic inflammatory cell infiltrate in the colonic mucosa but without significant abnormalities at colonoscopy. It encompasses at least two histopathologic entities (ie, collagenous and lymphocytic colitis). The recognition and characterization of microscopic colitis has markedly changed the approach to the evaluation and management of chronic diarrhea. The histologic features of collagenous and lymphocytic colitis are well known to most pathologists. By considering the clinical history and symptoms, the pathologist should be able to reach the correct diagnosis in most cases. However, the spectrum of morphologic changes associated with watery diarrhea syndrome appears to be broader than originally thought. Morphologic changes more often associated with chronic inflammatory bowel disease or even chronic ischemic or infectious colitis have been noted in patients with clinically established microscopic colitis. The data presented in this article suggest that microscopic colitis is a heterogeneous entity, which includes both classic and "atypical" forms. Problems arise when cases do not fit the usual pattern or lack some of the findings that are expected. Pathologists should be aware of the presence of atypical forms of microscopic colitis.

Melanocytosis of the oesophagus: case report

“…Genellikle özofagus orta ve alt 1/3'lük kısmında görülmektedir (1,2). Nadir görülen ancak iyi tanımlanmış bir antitedir.…”

“…tarafından tanımlanmıştır (6). Etiyolojisi ve doğal seyri net olarak bilinmemesine karşın primer özofagial melanomaların prekürsör lezyonları olabileceği bildirilmektedir (1,(4)(5)(6).…”

“…Özofagial melanozis ya da özofagial melanositozis (ÖM), özofagus skuamöz epitelinde melanositik proliferasyon ve mukozada melanin birikimi ile giden benign klinikopatolojik bir antitedir (1). Etiyolojisi ve doğal seyri net olarak bilinmemesine karşın bazı yazarlar tarafından primer özofagial melanomaların öncü lezyonları olabileceği belirtilmiştir (1, 2).…”

Non-IBD colitides: clinically useful histopathological clues

“…However, some authors believe that the term microscopic colitis should be abandoned by the pathologist (and also by the clinician), because it is a misleading and inconclusive definition for both professional figures, in that it represents a sort of semantic umbrella for two actual entities, namely collagenous colitis and lymphocytic colitis (15,16). These conditions need to be correctly diagnosed to provide a clear direction to help clinicians to better target the treatment, even though these entities may often share important similarities, and probably represent morphologic different phases of one disease process.…”

“…5). Apart from forms also related to the use of drugs (ticlopidine, ranitidine, flutamide) (15)(16)(17), one must remember the close morphological similarity and correlation with celiac disease, which may be an associated condition. Thus, the identification of lymphocytic colitis should always prompt the clinician to exclude a concomitant celiac disease with the appropriate serological tests (18,19).…”