A sporadic prostate tumor morphologically and immunophenotypically identical to dermal cylindroma is reported for the first time. The patient was a 78-year-old man with normal prostate-specific antigen serum level. Histologically, basaloid epithelial islands with broad rims of basement membrane material and strong immunoreactivity for alpha-smooth muscle actin in peripherally sited cells were the most distinguishing features. The only obvious difference from typical dermal cylindroma was a lack of intratumoral Langerhans cells in the prostate neoplasm. Differentiation from all hitherto known variants of basal cell proliferative lesions of the prostate was straightforward. However, focal cylindromalike features have been reported in rare cases of otherwise typical basaloid proliferations of the prostate.