The diagnostic yield in submitting nevi for histologic examination

Background: Dermatologists have expertise in the clinical diagnosis of beni gn melanocytic nevi. However, there are no data to confirm the accuracy of diagnosis. Differences in the diagnostic accuracy between dermatologists an d nondermatologists with regard to cutaneous tumors has been infrequently s tudied. Objective: We examined the rate of malignant tumors occurring in lesions su bmitted for routine microscopic examination that were clinically diagnosed as benign melanocytic nevi. Methods: We conducted a study at a regional, non-hospital-based dermatopath ology laboratory using specimens submitted by physicians of various special ties who were practicing in a 5-state Midwest region of the United States, The preoperative and postoperative diagnoses were examined on the basis of information provided by the clinician and of the subsequent histopathologic diagnosis. A total of 7734 cutaneous pathology reports were reviewed, Spec imens submitted with a preoperative clinical diagnosis of mole or nevus, wi th or without a modifier, were examined and compared with postoperative mic roscopic diagnoses. Results: Of 1946 specimens clinically diagnosed and submitted as benign nev i, 45 (2.3%) were histologically diagnosed as malignant tumors. This includ ed 12 melanomas, 30 basal cell carcinomas, and 3 squamous cell carcinomas. For specimens submitted by dermatologists, the rate of malignant tumors inc reased when clinical information suggested findings beyond the classic beni gn clinical presentation with the addition of modifiers such as irritated o r atypical, or if a malignancy was considered in the differential diagnosis (trend for increasing clinical suspicion: P = .00002). Fewer dermatologist s than nondermatologists mistook a malignant tumor for a benign nevus (1.3% vs 3.8%,P = .003). Conclusion: Our data document that 2.3% of clinically diagnosed benign nevi were microscopically diagnosed as malignant tumors. Whether this malignanc y rate in clinically diagnosed, benign, melanocytic nevi is above or below the threshold to establish a policy for submission for histopathologic exam ination remains to be determined as a collective societal and medical profe ssional responsibility.