Phacomatosis pigmentokeratotica (PPK) is a characterized by the coexcistence of an epidermal nevus with sebaceous differentiation arranged along Blaschko’s lines and a speckled lentiginous nevus showing a checkerboard pattern. A 45-year old male presented with a brownish dome-shaped nodule on the left cheek. Additionally the physical examination revealed numerous brownish macules and pedunculated nodules unilaterally on the trunk. Also, multiple skin-colored papules that were suspected as nevus sebaceous were found on the face. These clinical manifestations are characteristic enough to make the diagnosis as PPK. A biopsy specimen from a brownish nodule on the cheek showed hyperkeratosis, parakeratosis and acanthosis of the epidermis. Throughout the dermis horn cysts with central keratinization were found. They were surrounded by eosinophilic cells between basophilic cells and the central horn cysts. Moreover, a single layer of flattened granular cells was interpolated between the horn cysts Final diagnosis was concluded as a trichoadenoma occurred in the patient diagnosed with PPK. There have been reports on tumors from pilosebaceous glands in PPK patients, and these skin tumors vary from nevus sebaceous to syringocystadenoma papilliferum. However, our case presents a trichoadenoma which is an unusual finding that has so far not been mentioned in association with PPK. For these reasons, it seems worthwhile to report this case.