Presence of white scales and keratin might guide accurate recognition of invasive SCC
In people with lighter skin phototypes, squamous cell carcinoma (SCC) is typically nonpigmented and must be distinguished from other nonpigmented tumours. Although the dermoscopic features of SCC are well-known, some SCCs are challenging to recognize even with dermoscopy.
To investigate the clinical and dermoscopic features responsible for an inaccurate clinical diagnosis of invasive SCC and potential clues that could help in the recognition of this tumour.
We retrospectively screened our institutional database for clinically misdiagnosed SCCs over a 10-year time period (2013–2023). We then presented 10 expert dermoscopists with a series of clinical and dermoscopic images of misdiagnosed invasive SCCs and sought their opinion.
In total, 73 SCCs from 73 patients (55 men and 18 women) aged 37–97 years (mean 78.8) were included. Most tumours were located on the cheek (21%), followed by the forehead (16%), nose (12%) and scalp (12%). Thirty-seven SCCs were misdiagnosed as basal cell carcinoma, 15 as actinic keratosis, 10 as irritated seborrhoeic keratosis, 7 as Bowen disease, 2 as viral warts and 2 as cutaneous horn. White scales and keratin were voted by the experts as the main features (n = 34/73) that might have helped in the accurate clinical diagnosis of the included SCCs.
The dermoscopic characteristics of invasive SCC might overlap with other types of tumours. In challenging tumours, the presence of white scales and keratin might guide the accurate recognition of invasive SCC.
Source:
Katarzyna Korecka, Paweł Pietkiewicz, Bengü Nisa Akay, Iulia Badiu, Enzo Errichetti, Konstantinos Liopyris, Caterina Longo, Ashfaq Marghoob, Cristian Navarrete-Dechent, John Paoli, Verce Todorovska, Aimilios Lallas, How do we recognize a difficult squamous cell carcinoma? A retrospective analysis of clinically and dermoscopically misdiagnosed tumours, Clinical and Experimental Dermatology, Volume 50, Issue 10, October 2025, Pages 2016–2021, https://doi.org/10.1093/ced/llaf255