Value of histopathologic analysis of skin excisions by GPs

The clinical diagnoses of skin lesions in general practice may sometimes not be very accurate. The aim of this study was to compare clinical versus final histopathological diagnosis status (benign, premalignant/malignant) in 4595 consecutive submissions by GPs. The final diagnosis was pre-malignant or malignant in 215 cases (4.7%). From the 4436 lesions clinically diagnosed as benign, 134 (3.0%) were premalignant or malignant on final histological diagnosis. From the 159 lesions clinically diagnosed as premalignant or malignant, 78 (49.1%) were in fact benign, and 81 (50.9%) were indeed pre-malignant or malignant on final diagnosis. The sensitivity for a malignant diagnosis was 38%, and the specificity 98%. The proportion of pre-malignancies or malignancies was 0.9% below and 9.2% above the age of 40 years. In conclusion, histopathological investigation of skin excisions by GPs yields a high percentage of unexpected pre-malignancies and malignancies. The number of misdiagnoses was age dependent, with a proportion of 1% and 9% of pre-malignancies/ malignancies in patients below and above the age of 40 years, respectively. This indicates that all skin excisions by GPs must undergo routine histopathological investigation to ensure that serious malignancies are not missed.