Multiple basal cell carcinoma and internal malignant tumors.

One hundred ninety-six patients with multiple basal cell carcinoma were studied to clarify the relationship between multiple basal cell carcinoma and internal malignant neoplasms. No substantial deviations between the expected number and the observed number of cases of internal malignant neoplasms were found. On examination of patients who had histories of arsenic intake, a markedly high number of internal tumors were found in women but not in men. The figures are too low to prove that arsenic treatment can cause an increase in the incidence of internal malignant neoplasm, but they do indicate that more comprehensive studies are needed.