Squamous-Cell Carcinoma of the Scalp Arising in Lesions of Discoid Lupus Erythematosus

Squamous-cell carcinoma may arise in scars of chronic discoid lupus erythematosus. Although there have been 19 cases reported previously, detailed histopathologic features of this entity have not been recorded. We report a patient with extensive chronic discoid lupus erythematosus involving the scalp with subsequent development of multiple squamous-cell carcinomas. The tumors were locally aggressive with recurrences and invasion into the underlying skull and dura. The patient died of respiratory failure 4 1/2 years after initial surgical treatment. There was no clinical evidence of metastasis. Squamous carcinoma arising in discoid lupus erythematosus can be regarded as a low-grade carcinoma. Although about 20% of patients developed local recurrences and metastasis developed in about 30%, fatality occurred in only two patients (10.5%). Pertinent literature is reviewed, and the histopathologic findings, differential diagnosis, and biologic behavior of this tumor are discussed.