Introduction. Nevus sebaceous is a rare congenital hamartoma, composed of epidermis, sebaceous glands, sweat glands and hair follicles. It is possible to develop secondary tumors in the area of nevus sebaceous during the lifetime, most often after puberty. Secondary lesions are most often benign, while malignant lesions may occur but significantly less frequently. Case report. We present the case of a 21-year-old patient who came for an examination due to the appearance of a nodule in the area of a yellowish lesion on the head. The yellowish lesion was present since birth, and the nodule appeared about a year before. The dermoscopic examination of the lesion was nonspecific. The final diagnosis of eccrine poroma as a secondary lesion in nevus sebaceous was made by pathohisto-logical analysis. Conclusion. Every secondary tumor in nevus sebaceous deserves full attention, with either close follow up, or excision with pathohistological analysis.