Pits of the hands and feet are a hallmark of the nevoid basal cell carcinoma syndrome. These are observed in approximately one half of the adult patients with this disorder. Once developed the pits are permanent, specific, and unique in appearance, allowing diagnosis of this important syndrome by visual inspection. The finding of several other major signs in the subject furthers confirmation. The pits are asymptomatic and are acquired usually during the second decade of life or later, although they may, rarely, be present earlier. Pits occur in other dermatoses, but significant clinical and characteristic histopathologic changes permit differential diagnosis. The microscopic observation of basalar budding beneath the pit introduces the question of whether the defective epithelium may have a slightly increased propensity for forming basal cell cancer.
Howell JB, Mehregan AH. Pursuit of the Pits in the Nevoid Basal Cell Carcinoma Syndrome. Arch Dermatol. 1970;102(6):586-597. doi:10.1001/archderm.1970.04000120004002