Utilization and utility of immunohistochemistry in dermatopathology.
Immunohistochemistry (IHC) is considered a valuable ancillary tool for dermatopathology diagnosis, but few studies have measured IHC utilization by dermatopathologists or assessed its diagnostic utility. In a regionalized, community-based dermatopathology practice, we measured IHC utilization (total requests, specific antibodies requested, and final diagnosis) over a 12-month period. Next, we assessed diagnostic utility by comparing a preliminary "pre-IHC" diagnosis based on routine histochemical staining with the final diagnosis rendered after consideration of IHC results. The dermatopathology IHC utilization rate was 1.2%, averaging 3.6 stains requested per case. Melanocytic, hematolymphoid, and fibrohistiocytic lesions made up 23%, 18%, and 16%, respectively, of the total cases requiring IHC. S100 and Melan A were the most frequently requested stains, ordered on 50% and 34% of IHC cases, respectively. The utility study revealed that IHC changed the diagnosis in 11%, confirmed a diagnosis, or excluded a differential diagnosis in 77%, and was noncontributory in 4% of cases. Where IHC results prompted a change in diagnosis, 14% were a change from a benign to malignant lesion, whereas 32% changed from one malignant entity to another. IHC is most commonly used in cutaneous melanocytic and hematolymphoid lesions. In 11% of dermatopathology cases in which IHC is used, information is provided that changes the H&E diagnosis. Such changes may have significant treatment implications. IHC is noncontributory in only a small percentage of cases.
Department of Pathology and Laboratory Medicine, University of Calgary and Calgary Laboratory Services, Calgary, Alberta, Canada.
Karen A
KA
Naert
Martin J
MJ
Trotter
D000704:Analysis of Variance; D014408:Biomarkers, Tumor / Q000032:analysis; D003880:Dermatology / Q000379:methods*; D003937:Diagnosis, Differential; D006801:Humans; D007150:Immunohistochemistry / Q000706:statistics & numerical data*; D010336:Pathology / Q000379:methods*; D011237:Predictive Value of Tests; D011379:Prognosis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000737:chemistry / Q000175:diagnosis* / Q000473:pathology; D013194:Staining and Labeling / Q000706:statistics & numerical data
D014408:Biomarkers, Tumor