Dermoscopic Features of Subungual Squamous Cell Carcinoma: A Study of 44 Cases

Abstract

Background: Subungual squamous cell carcinoma (SSCC) is the most frequent tumor of the nail apparatus. Its diagnosis is often missed or delayed because the clinical presentation is atypical and can mimic other conditions. Accurate diagnosis can only be made by performing an appropriate surgical biopsy, but biopsy is painful and often leaves definitive dystrophic scars. The use of dermoscopy, a noninvasive technique, has been described to be useful for the preoperative evaluation of nail diseases. Objectives: To define the different clinical and dermoscopic presentations of SSCC and to compare them with onychomatricoma-associated clinical and dermoscopic features published in our previous study. Methods: A retrospective review of 44 cases of SSCC seen in our institution over an 8-year period. Six observers scored 19 clinical criteria and 14 dermoscopic criteria as present or absent. Then, we compared those data to a previously published study about the preoperative diagnosis of onychomatricoma. Results: Only 1 dermoscopic criterion was significantly associated with SSCC compared to onychomatricoma: localized hyperkeratosis (odds ratio, OR = 6.25, p = 0.012, 95% confidence interval CI = 1.50-26.01). In contrast, parallel edges (OR = 0.03, p < 0,001, 95% CI = 0.003-0.20) and sharp demarcation of the lesion (OR = 0.24, p = 0.004, 95% CI = 0.09-0.63) can statistically significantly be considered as in favor of onychomatricoma. By contrast, we believe that the presence of unparalleled lateral edges of the nail lesion or of fuzzy edges are more in favor of SSCC. Conclusions: Dermoscopy of the nail plate and of the nail free edge in SSCC provides useful information in order to better select cases to be submitted to biopsy.

Intraoperative dermoscopy features of subungual squamous cell carcinoma: a study of 53 cases

“…For this study, dermoscopic evaluation concerned only the intraoperatively observed features on the nail matrix and bed. Nail plate dermoscopy of the SU‐SCC in some of the cases included in the present study were previously reported by Teysseire et al 16 . but the series is not exactly the same because of the different inclusion time frame.…”

“…We recently published a study evaluating the preoperative clinical and dermoscopic features of 44 cases of SU-SCC. 16 The aim of that study was to define these features using noninvasive investigations to select patients for biopsy, and it described the nail plates and periungual skin, including the lateral folds, which were dermoscopically accessible before surgery with the nail plate kept in place. Intraoperative dermoscopy is an accessible and affordable technique performed on the nail matrix and bed after avulsion of the nail plate.…”

Onychoscopy

“…• Onychoscopic manifestation: The key for diagnosis is pathological examination. However, it has been suggested that nail dermoscopy can be used to better select patients for invasive procedures (Teysseire et al 2017).…”

“…However, local progression (up to 60% of cases of bone involvement in the distal phalanx) and recurrences are the main concern for clinicians (Lambertini et al 2018). • Differential diagnosis: Viral warts, onychomycosis, posttraumatic nail dystrophy, subungual exostosis, chronic paronychia, periungual fibrokeratoma, onychopapilloma, onychomatricoma (Teysseire et al 2017), melanoma, and subungual keratoacanthoma (Richert et al 2013).…”

Malignancy of the nail apparatus – clinical and dermoscopic analysis

“…The role of dermoscopy in the diagnosis of NASCC is poorly investigated [11]. Teysseire et al, who analysed dermoscopic criteria of 44 cases of NASCC, concluded that frequent dermoscopic features were: irregular and unparalleled borders, hyperkeratosis underneath the nail plate, splinter haemorrhages and white longitudinal lines.…”