A 52-year-old man presents for evaluation of moles. His paternal family history is positive for basal cell carcinoma and negative for melanoma. Scattered nevi are noted on his trunk and extremities but are not clinically suspicious when viewed under a dermatoscope. Of concern is a pigmented lesion situated within his right nasolabial fold.
Submit your diagnosis to see full explanation.
Basal cell carcinoma is the most common form of cancer. An estimated 4 million new cases are diagnosed each year in the United States with the incidence increasing in both the United States and the United Kingdom.1-3 Predisposing factors of basal cell carcinoma include history of chronic sun exposure and positive family history. The most common locations are the head and neck.
Subtypes of basal cell carcinoma include infiltrative, morpheaform, superficial, and nodular. Pigmented basal cell carcinoma is a rare variant of the nodular subtype. Unlike the common form, pigmented basal cell carcinomas have a predilection for darker-skinned individuals.4 As pigmented basal cell carcinoma is often mistaken for melanoma, dermoscopy may aid in differentiation, although definitive diagnosis requires histology.5
Stephen Schleicher, MD, is director of the DermDox Center for Dermatology, as well as an associate professor of medicine at Commonwealth Medical College and a clinical instructor of dermatology at Arcadia University and Kings College.
1. Basal cell carcinoma overview. Skin Cancer Foundation website. https://www.skincancer.org/skin-cancer-information/basal-cell-carcinoma/. Updated May 2019. Accessed October 31, 2019.
2. Muzic JG, Schmitt AR, Wright AC, et al. Incidence and trends of basal cell carcinoma and cutaneous squamous cell carcinoma: a population-based study in Olmsted County, Minnesota, 2000 to 2010. Mayo Clin Proc. 2017;92(6):890-898.
3. Reinau D, Surber C, Jick SS, Meier CR. Epidemiology of basal cell carcinoma in the United Kingdom: incidence, lifestyle factors, and comorbidities. Br J Cancer. 2014;111(1):203-206.
4. Coleman CI, Wine-Lee L, James WD. Pigmented basal cell carcinoma: uncommon presentation in blue-eyed patients. JAMA Dermatol. 2013;149(8):995-996.
5. Dermoscopy of basal cell carcinoma. DermNet NZ website. https://www.dermnetnz.org/cme/dermoscopy-course/dermoscopy-of-basal-cell-carcinoma/. Published 2008. Accessed October 31, 2019.