Clinical Implications of Histopathologic Diagnostic Discrepancies in Sinonasal Malignancies

Aims/Objectives: To evaluate the incidence of histopathologic diagnostic discrepancy for patients referred to our institution, identify pathologies susceptible to diagnostic error and to assess the impact on survival of histopathologic diagnostic discrepancies.

Materials/Methods: Four hundred and five patients with sinonasal cancers were identified from our institutional sinonasal database. Discordance between the outside pathologic report and the pathologic report performed at our institution was assessed. Chi-square and ANOVA methods were utilized to compare the significance of using additional studies (immunohistochemistry, in situ hybridization, and genetic markers testing) in obtaining histopathologic diagnoses. Overall survival and disease specific survival were analyzed using Kaplan–Meier and log rank methods.

Results: Discordance of overall histopathologic diagnoses was present in 23.9% (97/405) of reports, with sinonasal undifferentiated carcinoma, sarcoma, neuroendocrine carcinoma, and poorly differentiated carcinoma pathologies having the highest change in diagnosis (p < 0.01). A further 60% (244/405) had changes in histologic grade, subtype, or stage, with sarcoma and neuroendocrine carcinoma pathologies being most susceptible to change (p < 0.02). The change from a prior benign diagnosis to a malignant diagnosis upon review occurred in 1.7% of cases. The use of additional immunohistochemistry testing lead to a change in overall histopathologic diagnosis (p = 0.012), while in situ hybridization and testing for genetic markers testing did not. The 5-year overall and disease specific survival in patients with a change in histopathologic diagnosis was 55% and 70% compared with 72 and 82% respectively, in patients with no change in their diagnosis (p = 0.002 and p = 0.024, respectively). The 5-year overall survival in patients who had treatment prior to presentation at our institution was higher for those who did not have a change histopathologic diagnosis (75%) compared with those who had a change in histopathologic diagnosis (50%, p = 0.001).

Conclusion: Sinonasal pathology, and in particular, sinonasal undifferentiated carcinoma, sarcoma, neuroendocrine carcinoma and poorly differentiated carcinoma are prone to histopathologic misdiagnoses. Incorrect diagnosis is associated with reduced survival, which may be attributable to inadequate, inappropriate, or delays in treatment. Obtaining second opinions from experienced head and neck pathologists at a high-volume institution may potentially lead to a change in treatment recommendations that could result in improved survival in patients with sinonasal malignancies.

No conflict of interest has been declared by the author(s).