ABSTRACT Objective: To review the pathological diagnosis of possible cases and/or hidden cases of malignant mesothelioma (MM) between 2000 and 2012 using the Hospital-Based Cancer Registry database in the state of São Paulo, Brazil. Methods: Possible cases were retrieved by assessing the database. Inclusion criteria were being older than 30 years of age and having ICD-O-3 topography and morphology codes related to MM. A board of expert pathologists reviewed the pathology reports and requested paraffin blocks in cases that demanded revision. After staining with calretinin, D2-40, WT-1 (as positive MM markers) and Ber-EP4 and MOC31 (as negative MM markers), cases were divided and studied independently by a pair of pathologists to confirm or discard the diagnosis of MM. Results: Our sample comprised 482 cases from 25 hospitals, and 130 needed further histological revision. We received 73 paraffin blocks with adequate material. After board analysis, there were 9 cases with a definitive diagnosis of MM, improving the diagnostic rate in 12%. Two cases of previously diagnosed MM were discarded by review. Conclusions: Our results confirm that part of MM underdiagnosis and underreporting in Brazil is due to incomplete or mistaken pathological diagnosis. Objective andor (MM 200 201 HospitalBased Hospital Based Paulo Methods 3 ICDO3 ICDO ICD O ICD-O- revision calretinin D240, D240 D D2 40, 40 D2-40 WT1 WT 1 WT- as markers BerEP4 BerEP Ber EP4 EP Ber-EP MOC MOC3 markers, , Results 48 2 hospitals 13 7 material analysis 12 12% Conclusions 20 ICD-O D24 4 D2-4 D2-

Bezoars are foreign bodies impacted in the digestive tract resulting of their ingestion and accumulation, involving mainly the stomach. The most common types are phytobezoars, contaning vegetables, fiber and seed and the trichobezoar, made of hair. The present case is the description of a 25-year-old female with nonspecific dyspeptic symptoms associated to intestinal habit change. The diagnosis was suggested by Computerized Tomography in association with clinical history - initially omitted by the pacient - of trichophagia for 10 years. Treatment consisted of Anterior Gastrotomy and remotion of the bezoar.