Evaluation of diagnostic utility of step sections in dermatopathology: A prospective study of 200 consecutive punch biopsies

Abstract

Background: Obtaining deeper sections or step sections is a common practice for small skin biopsies. Much of the available literature highlights the importance of step sections in neoplastic diseases of skin. However, the routine dermatopathology practice in developing countries shows a predominant burden of nonneoplastic diseases, and the utility of step sections in this context has not been much reported. Objective: The study was aimed to evaluate the utility of prospective step sections in routine dermatopathology practice. Materials and Methods: The present study comprising 200 consecutive skin biopsies was carried out in a prospective manner. Three slides were prepared in each case: Slide 0 was prepared from the ribbon of tissue obtained from untrimmed block, step sections 1 and 2 were obtained at 50 μm and 100 μm depth, respectively. The diagnosis was rendered on slide 0 and subsequently reviewed after examining step section 1 and 2. Results: Of the 200 cases, additional findings on step sections were found in 18 cases (9%) which led to change in diagnosis in 10 (5%) cases. Step section 1 led to correct diagnosis in 6 cases (3%). Step section 2 led to correct diagnosis in 10 cases (5%); however, this was statistically not significant (P ≥ 0.065) when comparing to step section 1. Additional findings which led to diagnosis was most commonly found in the cases of borderline tuberculoid leprosy (5 out of 10 cases) followed by bullous disorders. Conclusion: We therefore believe that step sections improve the diagnostic accuracy in skin biopsies and they are, especially useful in suspected cases of Hansen's disease. There is no statistical advantage of step section 2 versus step section 1; although, step section 2 had shown to include all the additional findings which led to a change in diagnosis.