Cutaneous pigmented invasive squamous cell carcinoma: a case report with dermatoscopy and histology

Cutaneous invasive pigmented squamous cell carcinoma (SCC) is rare. There have previously been only a few case reports or small case series in the English literature [1-13]. In the largest published study there were five cases of pigmented invasive SCC in 46,791 archived cases of invasive SCC (approximately 0.01%) [2]. This compares to pigmented SCC in-situ (pigmented Bowen’s disease) in which the largest study found 52 of 951 (5.5%) consecutive cases of SCC in-situ to be pigmented [14]. The differential diagnosis of pigmented invasive SCC includes benign and malignant melanocytic neoplasms (melanoma and nevus) as well as pigmented types of benign and malignant epithelial neoplasms such as basal cell carcinoma (BCC), actinic keratosis (AK), SCC in-situ, seborrheic keratosis and melanoacanthoma [1, 12]. Our search has revealed five cases of pigmented invasive SCC with a description of dermatoscopy features [1, 9, 10, 12, 13] and in none of those cases was the diagnosis predicted. Case report