IN THIS issue of the ARCHIVES, Carag et al1 provide objective evidence in support of obtaining additional, so-called step or deeper sections when a diagnosis of actinic keratosis (AK) is rendered on microscopic examination of routine histological sections. In their study, they produced 10 additional slides taken at 50-µm intervals in each of 69 consecutive AKs diagnosed on initial sections. By this unusually thorough protocol, they identified additional histopathological changes that resulted in modified diagnoses in one third of specimens. Although not all of the newly discovered lesions were clinically significant, approximately 20% of the specimens revealed fully evolved, malignant keratinocytic neoplasms: squamous cell carcinoma (SCC) or basal cell carcinoma. Furthermore, a majority of the carcinomas identified in this study required more than 5 step sections. Although most of the newly discovered neoplasms were basal cell carcinomas or SCCs in situ, 2 were SCCs involving the dermis, therefore possessing the theoretical potential for metastasis.
Guillén DR, Cockerell CJ. Accurate Diagnosis of Cutaneous Keratinocytic NeoplasmsThe Importance of Histological Step Sections (and Other Factors). Arch Dermatol. 2000;136(4):535-537. doi:10.1001/archderm.136.4.535