Secondary review of extramural hematopathology cases for patients referred to an academic center: The increasing importance of subspecialized hematopathology practice.

Abstract

We sought to investigate the frequency of diagnostic changes in hematopathology cases referred to the University of Michigan during a 3-year period and explore which parameters contribute to diagnostic change. Pathology reports from hematology patients who came to the University of Michigan for a second opinion from 2017 to 2019 were reviewed. Diagnostic discrepancies were classified into major or minor. Specimen type, hematopathology board certification and practice time of the outside pathologists, referring practice type, and whether the second review was done at the referring institution were recorded too. Agreement in diagnosis by the above-listed specimen characteristics was analyzed. A total of 2786 cases were reviewed (2016 bone marrow and 770 tissue specimens). Disagreements in diagnosis were found in 263 cases (9.4% of total cases), and 163 (5.9%) were major disagreements. Among the major disagreements, 119 (73%) were in bone marrow specimens and 44 (27%) in tissue specimens. Among bone marrows, the most common revisions were myeloid neoplasm reclassifications (35.3%), whereas lymphoma subtype revisions comprised 70.4% of all changes in tissues. Univariate analysis showed that major disagreement rates were significantly higher in cases signed out by pathologists without hematopathology certification, those practicing for more than 10 years, and in cases from nonacademic institutions. When analyzing bone marrows and tissues separately, these differences remained significant only for bone marrows. Second review of pathology material serves as an important quality assurance and patient safety measure. Lack of hematopathology training of the referring pathologists may contribute to the rate of diagnostic discrepancy.