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Linear nevus sebaceous syndrome

2014; Medknow; Volume: 17; Issue: 4 Linguagem: Inglês

10.4103/0972-2327.144042

1998-3549

VenkatesanPrasanna Eswaradass, Leema Pauline, B. Kannan, Viveka Saravannan,

Hedgehog Signaling Pathway Studies

Case Report A 8-year-old male child born of consanguineous marriage presented with history of recurrent right focal seizures becoming generalized since childhood. He also had delayed milestones and mental retardation. He was admitted several times for his seizures since infancy. On examination, he had characteristic nevus over his forehead extending into the scalp along midline oriented vertically [Figure 1]. He also had right hemiplegia. We made a diagnosis of Linear nevus sebaceous syndrome (LNSS) and magnetic resonance imaging (MRI) showed left hemimegalencephaly (HME) [Figure 2].Figure 1: Vertically oriented forehead naevus along midlineFigure 2: (a) T 1 weighted image shows left hemimegalencephaly with agyria-pachygyria complex (b) T 2 weighted image shows left ventricle colpocephalyDiscussion LNSS, also called epidermal nevus syndrome, is a rare, sporadic neurocutaneous syndrome characterized by a linear sebaceous nevus of Jadassohn, mental retardation, and, seizures. The syndrome was originally described by Schimmelpenning and further defined by Feuerstein and Mims.[12] The skin lesions are characteristically found in scalp, face, or neck. A paramidline location of the nevus is typical with the lesion often vertically oriented from the middle of the forehead along the nose to the upper lip just lateral to midline. Hemangiomas, lipomas, hypopigmented lesions, and rarely café au lait spot have also been described. Among central nervous system (CNS) abnormalities, unilateral HME is the most common finding and is typically ipsilateral to the skin lesions. In addition, other neuronal migration abnormalities (pacygyria, agyria, heterotopia, etc.), vascular malformations, agenesis of the corpus callosum, Dandy-Walker syndrome, myelomeningocele, Arnold-Chiari malformation, and tumors have been reported.[345] HME is characterized by unilateral enlargement of a cerebral hemisphere and a normal contralateral hemisphere, cerebellum, and brainstem. It occurs in about 50% of LNSS. The most common MRI findings in HME are ventricular enlargement, increased signal intensity in white matter of the affected hemisphere on T2-weighted images, loss of delineation between white and gray matter and agyria.[67] HME is clinically characterized by seizures, mental retardation, and contralateral hemiparesis. Seizures are focal and may present as infantile spasms initially. Usually they are refractory and require hemispherectomy. Pathologically, HME is characterized by complete disorganization of the cortical cytoarchitecture without normal cortical layers and the area of the cortex is smaller than the contralateral side, suggesting abnormal proliferation of the white matter as the mechanism of hemispheric enlargement.[8] Hemihypertrophy of the face occurs in about 50% of patients ipsilateral to the nevus and hemiatrophy contralateral to the nevus is occasionally seen. Eye involvement occurs in about 33% of patients and includes lipodermoid scleral tumors, microphthalmia, corneal opacities, focal globe calcifications, and colobomas. Cardiac anomalies include coarctation aorta and ventricular septal defect. With increasing age, there is an increased incidence of skin, breast, salivary gland, stomach, esophageal, and bladder cancer. Conclusion LNSS is a rare neurocutaneous syndrome. Most common CNS abnormality associated with it is HME. It typically presents with seizures, mental retardation, hemiparesis, and linear nevus.