Postinflammatory hypopigmentation and hyperpigmentation are frequently encountered problems and represent the sequelae of various cutaneous disorders as well as therapeutic interventions. However, the underlying mechanisms and the variability individuals show for developing hypopigmentation or hyperpigmentation are not well understood. The authors propose an inherited individual chromatic tendency that is based on "weak" or "strong" melanocytes and their tendency to respond to trauma or inflammation with either hypopigmentation or hyperpigmentation. Clinical examples and management of both hypopigmentation and hyperpigmentation are discussed.

Of the patients with epidermal nevi, 10-18% may have disorders of the eye, nervous, and musculoskeletal systems. A predisposition to malignant neoplasms in ectodermal and mesodermal structures may also be found. There are six different epidermal nevus syndromes described so far: Proteus, congenital hemidysplasia with ichthyosiform nevus and limb defect syndrome, phakomatosis pigmentokeratotica, sebaceous nevus, Becker nevus, and nevus comedonicus. Thirty-five patients with epidermal nevus syndrome seen at the National Institute of Pediatrics in Mexico City during a 31-year period are described. This syndrome represented 7.9% of 443 patients with epidermal nevi; its relative frequency was 1 case per 11,928 pediatric patients and 1 case per 1080 dermatologic patients. Nine epidermal nevus syndrome patients (26%) had Proteus syndrome. Sebaceous nevus syndrome was found in six patients (17%), while the nevus comedonicus syndrome was found in three (8%). Two patients were diagnosed with phakomatosis pigmentokeratotica and one patient with congenital hemidysplasia with ichthyosiform nevus and limb defect syndrome. This is the first report of phakomatosis pigmentokeratotica and congenital hemidysplasia with ichthyosiform nevus and limb defect syndrome in Mexican patients. One patient had an inflammatory linear verrucous epidermal nevus with systemic involvement. Thirteen patients (37%) had keratinocytic nevi with systemic involvement. We propose the keratinocytic nevus syndrome to be defined as the association of a keratinocytic nevus with neuronal migration and/or musculoskeletal disorders in addition to a higher risk for mesodermal neoplasms.

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Background: Magnetic resonance imaging (MRI) findings suggestive of neurocutaneous melanosis (NCM) have been reported in asymptomatic patients with giant congenital melanocytic nevi (GCMN). Objective: To investigate the presence of NCM and the clinical neurologic status of patients with GCMN involving the head and neck. Methods: Thirteen patients with GCMN involving the head and neck were clinically examined by pediatric specialists in dermatology, ophthalmology and neurology. Electroencephalograms, noncontrasted and contrasted computerized tomography (CT) scans and MRI were performed. Results: Eleven of 13 patients with GCMN of the head and neck previously considered asymptomatic were found to present mild but evident neurologic alterations. No signs of NCM were found in the CT scans or in the MRI. Conclusions: Patients with GCMN of the head and neck may have associated neurologic alterations not related to the presence of neurocutaneous melanosis.

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