Angioelastose polipoide em biópsias colorretais

Abstract

INTRODUCTION AND OBJECTIVES: Elastofibromatous alterations of the gastrointestinal tract are generally characterized as polyps with an abnormal accumulation of elastic fibers, especially in the submucosa. They are little studied and described as isolated cases or small series. The largest series reports 13 cases. There are no published cases in Brazil. With the systematic use of colonoscopy in the prevention and early detection of colorectal cancer, polypoid lesions with characteristics of this alteration have been seen, but they appear to be underdiagnosed. Differential diagnoses are important in the practice of gastroenterologists and pathologists. Its pathogenesis has not yet been clarified. The aims of this study are: 1) describe the clinical and histopathological characteristics of a series of cases of colorectal elastofibromatous alterations seen in a reference laboratory in gastrointestinal pathology; 2) verify their frequency in colonoscopies with biopsies submitted for histopathological evaluation; 3) based on morphological observations, speculate on the possible pathogenesis of this alteration. MATERIALS AND METHODS: Descriptive study of a series of cases diagnosed in a laboratory, reference in gastrointestinal pathology, from January 2016 to October 2023. Reports were reviewed and information on age, sex, clinical manifestations, examination indication, topography, and endoscopic description of the lesions was noted. The histological slides, stained with hematoxylin and eosin, as well as special stains for the identification of elastic fibers and connective tissue matrix (Orcein, Weigert Van Gieson, and Masson's trichrome) and amyloid deposits (Congo red), were reviewed. In eight cases, immunohistochemical evaluation was performed with CD34 and smooth muscle antibody for characterization of blood vessels in the lesions. RESULTS: In 26 reports, 27 lesions were identified as elastosis and/or elastofibromatous alterations in the topography of the large intestine. One patient had two synchronous lesions. Twenty-six lesions were identified by staining with Hematoxylin-Eosin in conjunction with stains for elastic fibers. Eleven patients were male and 16 were female. The average age was 60.31 years (ranging from 49 to 73 years). All lesions were identified as polyps in endoscopy. For differential diagnosis with amyloidosis, Congo red staining was used with observation under polarized light. Immunohistochemical evaluation with markers of blood vessels showed an association of the lesion with anomalous blood vessels, consistent with vascular malformations. In none of the cases studied was there reference to extra-intestinal elastoses. CONCLUSION: Polyps with elastofibromatous alterations are diagnosed in services that receive a large volume of colon and rectal polyps for histopathological evaluation. In this series of cases, these lesions were identified in 0.03% of 92.037 colonoscopy examinations performed from January 2016 to October 2023. Their morphological characteristics are distinct from polyps of neoplastic or non-neoplastic epithelial nature, as well as from other mesenchymal polyps and should be recognized by pathologists. The diagnosis is suspected in sections stained with hematoxylin-eosin and confirmed by the use of histochemical method for elastic fibers. The histopathological characteristics are distinct from amyloid deposits and, when necessary, Congo red staining excludes this possibility. In our series, all cases had submucosal location and several of them showed characteristics similar to mucosal-submucosal polyps with vascular anomalies, noting vessels with muscular walls, larger than normal in the submucosa. Histopathological analysis combined with immunohistochemical evaluation suggests that elastotic alteration is related to the walls of anomalous vessels with increased and disorganized deposition of elastic fibers and other elements of the connective tissue matrix. Associated with this, there is a reduction in the lumen of the vessels, not only due to the accumulation of elastic fibers, but also due to the deposition of collagen matrix, suggesting that these anomalous vessels, in their more distal portions, underwent thrombosis and an anomalous organization process with reduction or disappearance of the vascular lumen (Fig.1and 2). Our data suggest an association between these elastofibromatous polyps and focal vascular anomalies in the submucosa of the large intestine. Due to their polypoid appearance and relationship with vessels, it is suggested that the term polypoid angioelastosis be used.