Biopsy of the lesion was performed, revealing basosquamous cell carcinoma (BSCC), also known as metatypical basal cell carcinoma. Basal cell carcinoma (BCC) is the most common malignancy worldwide with millions of new cases diagnosed each year in the United States.1,2 BSCC, an uncommon variant of BCC, represents approximately 2% of cases.3 Clinical appearance is variable; diagnosis is made by histologic examination, with lesions demonstrating features of both basal and squamous cell carcinoma.4 Once classified as “collision” tumors, BSCCs are now believed to be BCCs that undergo squamous differentiation.5
The majority of cases occur on the head and neck of elderly men. Unlike BCCs, BSCC lesions have significant metastatic potential and are aggressively invasive with high risk of recurrence. Treatment options include surgical excision, Mohs’ micrographic surgery, and radiation therapy.
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. Wong CSM. Basal cell carcinoma. BMJ. 2003;327(7418):794-798.
2. Basal cell carcinoma overview: the most common type of skin cancer. Skin Cancer Foundation website. https://www.skincancer.org/skin-cancer-information/basal-cell-carcinoma/. Reviewed May 2019. Accessed September 20, 2019.
3. Wermker K, Roknic N, Goessling K, Klein M, Schulze H-J, Hallermann C. Basosquamous carcinoma of the head and neck: clinical and histologic characteristics and their impact on disease progression. Neoplasia. 2015;17(3):301-305.
4. Betti R, Crosti C, Ghiozzi S, Cerri A, Moneghini L, Menni S. Basosquamous cell carcinoma: a survey of 76 patients and a comparative analysis of basal cell carcinomas and squamous cell carcinomas. Eur J Dermatol. 2013;23(1):83-86.
5. Oldbury JW, Wain RAJ, Abas S, Dobson CM, Iyer SS. Basosquamous carcinoma: a single centre clinicopathological evaluation and proposal of an evidence-based protocol. J Skin Cancer. 2018;2018:6061395.