Spotty skin pigmentation lesions, such as lentigines (small, brown to black, non or slightly elevated, round or irregular) and blue nevi (large, blue to black, domed lesion) observed primarily in the face, eyelids, ears, and borders of the lips are the most common clinical manifestation of CNC (77%). Lentigines tend to fade with the age, usually after the fourth decade of life.

Myxomas are frequent lesions in CNC patients; heart myxomas (53%) occur multicentrically, and in any, or all, cardiac chambers; skin myxomas (33%) are detected in the eyelid, the external ear canal, the nipple, the oropharynx, the female genital tract and the female pelvis. Breast myxomas are often bilateral and present in more than 70% of adult women with CNC.

Psammomatous melanotic shwannomas , very rare tumors (10%), may occur anywhere in the peripheral nervous system, but most frequently in the gastrointestinal tract and paraspinal symphatetic chain.

Breast ductal adenomas, unusual mammary tumors akin to intraductal papillomas have been detected in 3% of CNC cases.

Endocrine lesions in CNC include testicular neoplasms (33%), primary pigmented nodule adrenocortical disease (PPNAD) (26%), growth hormone (GH) and prolactin-producing pituitary tumors (14%) and thyroid cancer (5%).