Two patients had painful piezogenic pedal papules. Heel biopsies were performed on each patient and the pathologic findings of the painful piezogenic pedal papule are delineated. The possible pathogenesis is discussed in conjunction with the observation of small nonpainful pedal papules in 250 normal pairs of heels, and a study of the anatomy of the nonpainful pedal papule from the heels of ten deceased patients.
Schlappner OLA, Wood MG, Gerstein W, Gross PR. Painful and Nonpainful Piezogenic Pedal Papules. Arch Dermatol. 1972;106(5):729-733. doi:10.1001/archderm.1972.01620140073023