By evaluating statistics from the Charity Hospital Tumor Registry, it was determined that the presence of a skin cancer increases the probability of the same patient having another malignancy internally. Of 2,433 patients with skin cancer in the registry, 197 (8%) were found to have an associated malignancy of another organ. Of 10,709 persons examined in the Tulane Cancer Detection Clinic, 0.72% were found to have malignancies. Age-adjusted incidence rates are presented which even further suggest an increased incidence of internal malignancy in patients with skin cancer. The higher than expected rate for internal malignancies in skin cancer patients warrants complete history, physical examination, and laboratory procedures on patients with skin malignancies.
Carpenter CL, Derbes VJ, Jolly HW. Carcinoma of the Skin— A Guidepost to Internal Malignancy?. JAMA. 1963;186(7):621–623. doi:10.1001/jama.1963.03710070023004