The neurocutaneous melanosis (NCM) is a rare, neuroectodermal dysplasia defined by the association of giant or multiple, nonmalignant pigmented cutaneous nevi with leptomeningeal melanosis or melanoma. As a rule, the cerebral pathological substratum is characterized by a melanocytic infiltration of the leptomeninges, often leading to hydrocephalus. The most frequent clinical symptomatology starts early in life, with convulsive seizures, psychomotor delay, intracranial hyperpression: the prognosis is severe. Malignant melanomas can also occur. One 21 years-old patient affected by NCM with a giant bathing nevus and epilepsy is reported. Her psychomotor development was slightly delayed. Academic progress was disturbed by the frequency of seizures and the multiple dermatological surgeries, and she remained at the elementary school level. Her epilepsy appeared at seven years and became pharmacoresistant. It was a focal, left temporal epilepsy. Neuroimaging investigations were performed repeatedly, and demonstrated the progressive appearance of parenchymal lesions with T1 and T2 shortening, without contrast enhancement, at the pons (11 years), the two hippocampi (14 years), and of an atrophy of the cerebellum and the brainstem (19 years). No hydrocephalus, tumoral aspect, or meningeal involvement were demonstrated. This patient's case is peculiar because her neurological symptomatology consists only of focal epilepsy, unrelated to a tumor, with moderate cognitive impairment despite a rather long course of the disease. Her evolution raises the question of condidency to surgical treatment.