No statistical difference in the prevalence of palmar keratoses could be demonstrated in patients with cancer when compared to a control group of individuals who did not have overt cancer. Palmar keratoses occurred more frequently on the left than on the right hand and more frequently on the hypothenar eminences than elsewhere in both groups. The etiology and significance of palmar keratoses is unknown, but in the New York city area these lesions cannot be considered a stigma of cancer.
Stolman LP, Kopf AW, Garfinkel L. Are Palmar Keratoses a Sign of Internal Malignancy?. Arch Dermatol. 1970;101(1):52-55. doi:10.1001/archderm.1970.04000010054008