title: Simulators of squamous cell carcinoma of the skin: diagnostic challenges on small biopsies and clinicopathological correlation.
abstract: Squamous cell carcinoma (SCC) is a common and important primary cutaneous malignancy. On skin biopsies, SCC is characterized by significant squamous cell atypia, abnormal keratinization, and invasive features. Diagnostic challenges may occasionally arise, especially in the setting of small punch biopsies or superficial shave biopsies, where only part of the lesion may be assessable by the pathologist. Benign mimics of SCC include pseudoepitheliomatous hyperplasia, eccrine squamous syringometaplasia, inverted follicular keratosis, and keratoacanthoma, while malignant mimics of SCC include basal cell carcinoma, melanoma, and metastatic carcinoma. The careful application of time-honored diagnostic criteria, close clinicopathological correlation and a selective request for a further, deeper, or wider biopsy remain the most useful strategies to clinch the correct diagnosis. This review aims to present the key differential diagnoses of SCC, to discuss common diagnostic pitfalls, and to recommend ways to deal with diagnostically challenging cases.
authors.affiliation: Department of Pathology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Lower Kent Ridge Road, Singapore 119074.
authors.forename: Kong-Bing
authors.initials: KB
authors.lastname: Tan
authors.forename: Sze-Hwa
authors.initials: SH
authors.lastname: Tan
authors.forename: Derrick Chen-Wee
authors.initials: DC
authors.lastname: Aw
authors.forename: Huma
authors.initials: H
authors.lastname: Jaffar
authors.forename: Thiam-Chye
authors.initials: TC
authors.lastname: Lim
authors.forename: Shu-Jin
authors.initials: SJ
authors.lastname: Lee
authors.forename: Yoke-Sun
authors.initials: YS
authors.lastname: Lee