Neurocutaneous syndromes associated with pigmentary skin lesions

Neuropeptides Profile and Increased Innervation in Becker's Nevus

Background

Melanocytes are derived from neural crest, and various pigmentary disorders may accompany abnormalities in nerve system or develop following dermatome, suggesting that melanocyte and pigmentation may be closely related to neural factors. There are reports of Becker's nevus (BN) showing linear and segmental configuration, suggesting the association of BN with nerve system. However, there are no studies regarding the expression of neuropeptides in BN.

Objective

We investigated the expression of neuropeptides and innervation in BN.

Methods

Polymerase chain reaction (PCR) array of 84 genes related to neuronal process was done. Among the genes with 10-fold or more increase in lesional, real-time PCR was performed for neuropeptide Y (NPY), galanin, neurotensin (NTS) and their receptors skin compared to normal skin. IHC stain was done to look for the expression of NPY, galanin, NTS and their receptors and the distribution of protein gene products (PGP) 9.5 immunoreactive nerve fibers.

Results

PCR array revealed that 16 out of 84 genes related to neuronal process were increased by 10-fold or more in lesional skin. In real-time PCR of NPY, galanin, NTS and their receptors, statistically significant increase of NPY1R (p<0.05) and marginally significant increase of NPY2R, GAL2R, and NTS2R (p<0.1) was verified in lesional skin. In immunohistochemistry, NPY, NPY1R NPY2R, and NTS2R were highly expressed in lesional skin and increased PGP 9.5 immunoreactive linear nerve fibers were found in the epidermis of BN.

Conclusion

NPY, galanin, NTS and their receptors and increased innervation may play a role in the pathogenesis of BN.

Focus on Vitiligo: A Generalized Skin Disorder

Vitiligo is an acquired pigmentation disorder due to a disappearance of functioning melanocytes from the epidermis and clinically characterized by achromic patches, often spreading over time. It is still not fully understood how melanocytes disappear in vivo, inducing these peculiar lesions. There are three major hypotheses for the pathogenesis of the disease: the autoimmune hypothesis considers that the disappearance of melanocytes is due to an autoimmune effector mechanism, the neural hypothesis suggests that an accumulation of neurochemical substances is able to damage epidermal melanocytes, and the metabolic hypothesis indicates that an increased sensitivity of melanocytes to oxidative stress is the crucial factor of the disease. Besides these well accepted hypotheses there are also some new interpretations based on a defective adhesion of melanocytic cells, an imbalance in the epidermal production of cytokines and an altered expression of melanocyte receptors. All these theories seem to be based on convincing evidence, indicating that they may contribute in variable proportions to the disease. There is also reasonable evidence at present that vitiligo potentially involves the whole integument, suggesting that it is a generalized skin disorder probably including different cell types during the active phase of the disease. It appears that the different theories may integrate with each other, supporting the concept that in vitiligo there is a final common step, i.e. a loss of pigment in the epidermis as well as different, possibly interacting, pathways leading up to this conclusive result.

Cutaneous and ocular manifestations of neurocutaneous syndromes

Neurocutaneous syndromes are a heterogeneous group of congenital and hereditary disorders with manifestations in the skin and the nervous system, usually together with ocular features that represent diagnostic clues and potential sources of morbidity. Dermatologists and ophthalmologists often need to work together in identifying and managing patients with these conditions; herein, we focus on classic and under-recognized neurocutaneous syndromes. We begin with autosomal dominant genodermatoses characterized by hamartomas and tumors in the skin, eyes, and central nervous system: neurofibromatosis type 1, tuberous sclerosis complex, and PTEN hamartoma-tumor syndrome. This is followed by a discussion of two mosaic disorders, Sturge-Weber syndrome and neurocutaneous melanocytosis. In addition to providing an update on clinical presentations and evaluation of patients with these conditions, we review recent insights into their pathogenesis, drawing attention to relationships among the diseases on a molecular level and implications regarding treatment. We also highlight the major features of other neurocutaneous syndromes that have ocular findings plus pigmentary, vascular, hyperkeratotic, adnexal, connective tissue, photosensitive, and inflammatory manifestations in the skin.

Neurocutaneous Melanosis: An Atypical Presentation

An eleven-year-old male child presented with multiple small melanocytic nevi in a generalized distribution and a giant congenital melanocytic nevus (GCMN) over the lumbosacral area since birth. He had had difficulty in walking since the age of two and a half years. Histopathological examination revealed intradermal melanocytic nevi. Serial Magnetic Resonance Imaging (MRI) scans showed brainstem atrophy with central nervous system abnormality suggestive of neuromelanosis. Clinically and histologically, the diagnosis was suggestive of neurocutaneous melanosis (NCM). The present case is reported due to its clinical presentation of quadriparesis, which has been rarely reported as a manifestation of neurocutaneous melanosis.

Sexual precocity in hypomelanosis of Ito: mosaicism-associated case report and literature review

BACKGROUND

Hypomelanosis of Ito (HI), a neurocutaneous disorder characterized by hypopigmented skin lesions along Blaschko's line with multiple accompanying diseases, may occasionally present with sexual precocity.

METHODS

We reviewed cases of HI with sexual precocity reported in the literature and focused on collecting information on other associated organ abnormalities, chromosomal karyotype, and type of sexual precocity. We also present our own case report.

RESULTS

Five children with sexual precocity in HI were studied. All patients were full-term females without significant family history. Their ages ranged from three years to 11 years. Skin lesions involved the trunk and limbs. Developmental delay was present in all patients. Central nervous system involvement was found in four patients. Craniofacial abnormalities were present in four patients. Eye involvement was present in two patients. Limb abnormalities (brachydactyly and clinodactyly) were present in two patients. Skeletal organ involvement was present in three patients. Other skin lesions were present in three patients. Dental abnormalities occurred in one patient. Of the five patients, four demonstrated a peripheral type of sexual precocity, and one presented with central type sexual precocity. Vaginal bleeding was present in two patients. Chromosomal karyotype abnormalities were found in two patients, and mosaicism was present in one of these.

CONCLUSIONS

Hypomelanosis of Ito is a syndrome characterized by cutaneous signs frequently associated with nervous, ocular, and musculoskeletal system abnormalities. Although it is rarely reported in conjunction with HI, physicians should recognize sexual precocity as a possible associated symptom.

Ipsilateral café-au-lait macules, deafness, and pituitary microadenoma in a 35-year-old woman

BACKGROUND

The association between ipsilateral café-au-lait macules, deafness, and pituitary adenoma has not been described previously.

CASE REPORT AND RESULTS

A 35-year-old woman affected since birth with two café-au-lait macules, one measuring 15 x 20 cm, with an irregular shape, covering almost all of the left buttock, and the other measuring 6 x 13 cm on the front side of the left thigh, is described. For as long as the patient can remember, she has been totally deaf in the left ear, diagnosed as 100% congenital sensorineural deafness. In addition, a left-side pituitary microadenoma was detected at the age of 31 years. She was also found to have a transitional lumbosacral vertebra, and multiple dermatofibromas and nevomelanocytic nevi.

CONCLUSION

It is suggested that this association is not a coincidence, but is part of a neurocutaneous syndrome which has not been described previously.

Paget's disease of the breast in a woman with neurofibromatosis

Paget's disease of the breast is a rare and specific type of breast carcinoma in the nipple or areola. On the other hand, neurofibromatosis (NF) is also a rare neurocutaneous disease, which is inherited and affects mainly the skin and the nervous system. In addition, NF is rarely associated with malignant tumors. We present a case of Paget's disease concomitant with NF type 1 in a 66-year-old woman.

The rare phakomatoses

This article outlines the clinical, central nervous system, and neuropathologic features,pathogenesis, genetics, molecular biology, and neuroimaging characteristics of the rare vascular phakomatoses, melanophakomatoses, and organoid phakomatoses.

Hypomelanosis of Ito with Sturge-Weber syndrome-like leptomeningeal angiomatosis

The term hypomelanosis of Ito (HI) is applied to individuals with skin hypopigmentation following the lines of Blaschko (type 1a of patterns indicative of somatic mosaicism as defined by Happle). Even though originally described as a purely cutaneous disease, subsequent reports of HI have included a 30-94% association with multiple extracutaneous manifestations. The frequency of extracutaneous associations has led many authors to consider HI to be neurocutaneous disorder. We report a male infant with cutaneous hypomelanosis along the lines of Blaschko distributed on the left half of the body who developed status epilepticus. Neuroimaging studies disclosed an angiomatous enlargement of the right choroid plexus and a gyral pattern of cortical and subcortical calcification in the right occipital region. Thus a diagnosis could be made of HI and associated Sturge-Weber syndrome-like leptomeningeal angiomatosis. This previously unreported association lends further support to the consideration of hypomelanosis of Ito as a marker of somatic mosaicism with frequently associated neurologic abnormalities. A relationship between HI and Sturge-Weber syndrome, two neuroectodermal disorders with a genetic mosaicism basis, might be possible due to nonallelic twin-spotting which in the embryologic period would define an abnormal development of neural, vascular, and cutaneous structures.

Streptococcal exanthem in a blaschkolinear pattern: clinical evidence for genetic mosaicism in hypomelanosis of ito

Due to the presence of two different clones of cells in early embryogenesis, numerous congenital and acquired dermatoses have a linear distribution following the lines of Blaschko. Acquired inflammatory skin diseases are rarely observed in linear patterns. Our patient was born with macrocephaly, left eye glaucoma, and a left facial and contralateral corporal hemihypertrophy, cerebral dysgenesis, and skeletal abnormalities. Hypopigmented S-shaped linear macules on the trunk and linear streaks on the arms and legs were compatible with hypomelanosis of Ito. At 5 years of age the patient presented with an erythematous follicular exanthem compatible with scarlet fever exclusively in the lines of Blaschko. This fact suggests a genetic mosaicism.

Neurocutaneous melanosis in association with encephalocraniocutaneous lipomatosis

We describe a white female infant with neurocutaneous melanosis (NCM) and encephalocraniocutaneous lipomatosis (ECCL). Multiple, giant and small congenital melanocytic nevi (CMN) were observed on the head, neck and trunk and involved 70% of body surface area. Histologic examination of several CMN revealed atypical nodular proliferations of dermal nevomelanocytes. In a small (<1 cm) truncal CMN, single and dyscohesive intraepidermal nests of atypical nevomelanocytes simulating a superficial spreading melanoma, were observed. The placenta was grossly normal and histologically demonstrated multiple banal appearing nevomelanocytes within the stroma of its villi. At the 17-month follow-up no evidence of primary or metastatic melanoma was present. This previously undescribed association of NCM, ECCL and placental nevomelanocytes provides strong support for the hypothesized causal role of anomalous neural crest morphogenesis and migration in the development of all three disorders. The genetic mechanism underlying these complex birth defects has been hypothesized to result from the action of lethal autosomal dominant genes surviving by mosaicism.

Management of large birthmarks

Birthmarks are commonly seen in neonates. Most are insignificant incidental findings and straightforward in their diagnosis and management. Others are of more serious concern and may require intervention for medical or cosmetic reasons. They may also be an indication of abnormalities in other organ systems. This chapter will focus on the diagnosis and management of large vascular and pigmented birthmarks. A multidisciplinary team approach involving paediatricians, dermatologists, plastic surgeons and other specialists is often required in the management of these children.

Localized pruritus: a presenting symptom of a spinal cord tumor in a child with features of neurofibromatosis

Central nervous system (CNS) and spinal cord tumors are not uncommon in patients with neurofibromatosis (NF); however, it is impossible to select patients with NF who are at a particularly high risk. Localized pruritus may be a clue to the presence of a spinal cord or CNS tumor. This is the first report of an infant with features of NF, whose presenting symptom of a spinal cord tumor was localized symmetrical dermatomal itch. Moreover, we review the literature of localized pruritus in CNS and spinal cord tumors and peripheral nervous system conditions.

Hypomelanosis of Ito: clinical syndrome or just phenotype?

The term hypomelanosis of Ito is applied to individuals with skin hypopigmentation along the lines of Blaschko. Even though originally described as a purely cutaneous disease, subsequent reports have included a 33% to 94% association with multiple extracutaneous manifestations mostly of the central nervous and musculoskeletal systems leading to frequent characterization as a neurocutaneous disorder. A number of reports claimed familial occurrence and supported single gene inheritance for hypomelanosis of Ito, but none has been proved. Miscellaneous chromosomal mosaicisms have been demonstrated in some but not all affected individuals. Thus, it has been suggested that hypomelanosis of Ito is not a single condition but rather a nonspecific manifestation (ie, a phenotype) of chromosomal mosaicism and that this term should now be dropped. In this article, we review these developments focusing on the neurologic and genetic aspects of hypomelanosis of Ito. Our personal experience with 41 hypomelanosis of Ito patients and literature review led us to conclude that (1) the term hypomelanosis of Ito has been often misapplied to individuals with nonspecific "patchy depigmentation of the skin" who had several conditions of different etiologies; (2) the white matter involvement seen at neuroimaging in most of our hypomelanosis of Ito patients was similar to that reported in well-defined neurocutaneous disorders, including Sjögren-Larsson syndrome and incontinentia pigmenti; (3) whatever figures we take for associated central nervous system abnormalities in hypomelanosis of Ito, these represent the most frequent extracutaneous findings and, therefore, the use of the term neurocutaneous disorder for hypomelanosis of Ito might well be appropriate.

Segmental nevus depigmentosus: analysis of 20 patients

Achromic nevus or nevus depigmentosus is a cutaneous abnormality consisting of a hypopigmented macular lesion which can present as circumscribed irregular, oval, or round or as a unilateral band or streak with a blocklike configuration or arranged along one or more Blaschko lines. When it is systematized, it is indistinguishable from hypomelanosis of Ito. Pigmentary anomalies along the lines of Blaschko can be associated with systemic features. For these reasons, 20 children, referred consecutively for evaluation of segmental, linear achromic nevus, were evaluated to define the incidence of associated abnormal systemic features. Extracutaneous abnormalities were present in 2 of 20 children (10%). The anomalies consisted of pes cavus ipsilateral to the hypopigmentation in one child and mental retardation, seizures, and hemihypertrophy in the second. This study confirms that achromic nevus, even when distributed along Blaschko lines, is commonly a benign lesion that is associated with systemic features in a small minority of cases.

Hypomelanosis of Ito: no entity, but a cutaneous sign of mosaicism

Hypomelanosis of Ito is a neurocutaneous phenotype comprising pigmentary anomalies, neurological defects, structural malformations, and chromosomal abnormalities. It has been described as a distinct multisystem birth defect or, more specifically, as a neurocutaneous syndrome. The main purpose of this study is to provide evidence that this disorder does not exist as a syndrome. Rather, it is a causally nonspecific pigmentary disorder caused by genetic mosaicism.

Diagnosis and management of tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is an autosomal-dominant neurocutaneous disorder with a high spontaneous mutation rate. Understanding of this disorder has greatly increased in recent years. Two chromosomal loci can produce the TSC phenotype: 9q34 and 16p13. These appear to code for proteins that have a tumor suppressor function. TSC results in hamartomas that affect various organ systems, most commonly brain, skin, heart, and kidney. Previously thought to consist of intractable seizures, facial angiofibromas, and dementia, increasing numbers of persons with less severe involvement have been identified. Diagnostic criteria, various types of lesions, and medical management are reviewed.

Linear hypopigmentation and hyperpigmentation, including mosaicism

Linear streaks of hypopigmentation or hyperpigmentation along Blaschko's lines are currently grouped under the names hypomelanosis of Ito (HI) and linear and whorled hypermelanosis (LWH). Recent studies have suggested that these linear pigmentary anomalies reflect underlying genetic mosaicism. Mosaic individuals are composed of two or more genetically distinct cell populations, a normal and an abnormal population. In HI and LWH, the types of genetic defects that are detectable in the abnormal population are highly variable, including tetraploidy, partial or complete trisomies, translocations, and point mutations. These results, together with recent studies indicating the incidence of extracutaneous anomalies is lower in HI but higher in LWH than previously estimated, have important clinical implications. The need for a revised nomenclature as well as possible modifications in current recommendations for patient management are discussed.

A study of large congenital melanocytic nevi and associated malignant melanomas: review of cases in the New York University Registry and the world literature

BACKGROUND

Patients with large congenital melanocytic nevi (LCMN) are at greater risk for the development of malignant melanoma (MM) than are persons in the general population.

OBJECTIVE

Our purpose was to identify the clinical features of LCMN in those patients in whom MMs actually developed.

METHODS

The records of 117 patients in the New York University Registry of LCMN and the reports of 172 cases of LCMN in the world literature were studied.

RESULTS

Of the 289 cases of LCMN studied, 34 patients (12%) had primary cutaneous MMs within their nevi; in two additional patients, MMs developed at cutaneous sites other than within their nevi. All patients in whom MM developed within LCMN had nevi in axial locations; however, 91% of the LCMN were axial. No MM was found that had arisen in any of the 26 LCMN confined to the extremities. In addition, no MM was found that had arisen in thousands of satellite nevi.

CONCLUSION

When MM develops within an LCMN, it generally does so in those LCMN in an axial location. The absence of cases of MM arising in LCMN confined to the extremities suggests that such nevi represent lower risk lesions, but the number of extremity nevi analyzed was too small to allow definitive conclusions. A striking finding was the absence of MMs arising in satellite nevi.

The occurrence of cutaneous nerve endings and neuropeptides in vitiligo vulgaris: a case-control study

Pioneering studies both in humans and animals have demonstrated an association between the peripheral nervous system and epidermal melanocyte destruction. The presence of certain neuropeptides and neuronal structural markers in peripheral nerve fibres was investigated in involved and uninvolved vitiligo skin and compared with normal healthy skin. A group of 18 vitiligo vulgaris patients and matched healthy volunteers participated in the investigation. The indirect immunofluorescence technique was employed. There was a tendency for a reduction in the number and intensity of low affinity (p75) nerve growth factor receptor immunoreactive (NGFr-IR) basal keratinocytes in involved vitiliginous skin (P < 0.06) compared with control skin, while the number of NGFr-IR nerve fibres was significantly increased (P < 0.01). The number of calcitonin gene-related peptide (CGRP)-IR nerve fibres in the epidermis and papillary dermis was dramatically increased in involved skin as compared with control skin (P < 0.01) and with uninvolved skin (P < 0.05). No clear difference could be found in the distribution of vasoactive intestinal polypeptide (VIP)- and neuropeptide tyrosine (NPY)-IR nerve fibres. A different structural appearance of the peripheral nervous system as well as a changed balance of neuropeptides in vitiliginous skin point to a critical role of the nervous system in the pathogenesis of vitiligo.

Neurocutaneous melanosis: clinical features of large congenital melanocytic nevi in patients with manifest central nervous system melanosis

BACKGROUND

Patients with a large congenital melanocytic nevus (LCMN) may have associated leptomeningeal melanocytosis with or without central nervous system (CNS) melanomas. These patients are considered to have neurocutaneous melanosis, a disorder that, when symptomatic or otherwise manifest neurologically, carries a poor prognosis even in the absence of malignancy.

OBJECTIVE

Our purpose was to identify typical clinical features in patients who have manifest CNS melanosis in association with LCMN.

METHODS

The records of 117 patients with LCMN in the New York University Registry of LCMN and the reports of 172 cases of LCMN in the world literature were included for features that might signal a high risk for the development of manifest CNS involvement.

RESULTS

Of the 289 patients with LCMN, 33 had manifest CNS melanosis. In all 33 in whom symptomatic neurocutaneous melanosis was diagnosed, the LCMNs were present in a posterior axial location on the head, neck, back, and/or buttocks. "Satellite" nevi were known to be present in 31 of the 33 patients.

CONCLUSION

Patients with LCMN in a posterior axial location, especially when associated with "satellite" melanocytic nevi, are at greater risk for the development of manifest neurocutaneous melanosis than patients with LCMN limited to the extremities or those who are lacking satellite nevi.