Introduction: The diagnosis of cancer is directly conditioned to the assessment of the histology of the tumor. The histopathological review aims to minimize diagnostic mistakes and, thus, avoid unnecessary therapeutic efforts for the patient. The literature lacks data that evaluate the impact of discrepancy in histopathology in the oncological conduct, which is the objective of the present study. Materials and methods: Retrospective assessment of histopathology reports of solid neoplasms available in the digital collection of the Pathological Department of State University of Campinas (UNICAMP) in 2016 to 2018.Previous reports were compared with the results of the histological review, being possible to document the percentage of discrepancy between them. It was analyzed how the discrepancy found would interfere in the oncology conduct.Results: 1117 solid neoplasia reports were analyzed with their respective histological reviews; 306 cases (27,39% -95% CI 24,80-30,11) had a diagnosis discrepancy after the review. Of these, 212 (18,98% -95% CI 16,72-21,40) would have changes in cancer management if the review report was considered correct.The areas with the highest percentage of change in treatment were, respectively, bone and soft tissue tumors, gastrointestinal tract and central nervous system (51,58;31,25;31,66). Head and neck tumors and tumors of the female genital tract have the lowest percentages of discrepancy (8,53% -95% CI 5, 15 and 23,59) and therapeutic changes (6,88 and 15,81). Conclusion: This study showed a higher percentage of histopathological discrepancy than that reported in the literature. It was found that cancer therapy would be subject to changes in 18.98% of cases after the histological review. These results are a warning to professionals involved in cancer care of how the discrepancy in histopathology can interfere in planned treatment.