Pigmented skin lesions displaying regression features: Dermoscopy and reflectance confocal microscopy criteria for diagnosis.

Melanomas and nevi displaying regression features can be difficult to differentiate. To describe reflectance confocal microscopy features in benign and malignant pigmented skin lesions characterized by regression features in dermoscopy. Observational retrospective study. Inclusion criteria were presence of dermoscopic features of regression; availability of clinical, dermoscopic and RCM imaging; definite histopathologic diagnosis. The study sample comprised 217 lesions; 108 (49.8%) melanomas and 109 were benign lesions, of which 102 (47.0%) nevi and 7 (3.2%) lichen planus-like keratosis (lplk). Patients with melanoma were significantly older than those with benign lesions (61.9 ± 15.4 vs 46.1 ± 14.8; P < 0.001) and a higher proportion of melanomas displayed dermoscopic regression structures in more than 50% of lesion surface (n = 83/108; 76.9%; P < 0.001). On RCM examination, pagetoid cells were significantly more reported in melanoma group, than in benign lesions (86.1% vs 59.6%; P < 0.001) and were more frequently widespread distributed (65.6% vs 20.0%; P < 0.001) and both dendritic and roundish (36.6% vs 15.4%; P < 0.001) in shape. Aspecific architecture at the dermo-epidermal junction (DEJ) was more commonly seen among melanomas than benign lesions (23.1% vs 11.9%; P = 0.002) with higher presence of dendritic and both dendritic and roundish atypical cells at the DEJ (28.7% vs 18.3% and 19.4% vs 3.7%; P < 0.001, respectively). Focal pagetoid infiltration and ringed or clod patterns were more commonly seen in benign lesion. In conclusion, the correct interpretation of regressing lesions remains a challenge, assessing carefully the extent and characteristics of architectural and cytologic atypia on RCM is an additional piece of the complex puzzle of melanoma diagnosis.

Complex Truncal Masses in the Setting of CLOVES Syndrome: Aesthetic and Functional Implications.

BACKGROUND: Congenital lipomatous overgrowth, vascular malformations, epidermal nevi, and skeletal abnormalities (CLOVES) is a complex overgrowth syndrome with dramatic aesthetic and functional implications. The truncal masses characteristic of CLOVES syndrome are described as vascular malformations or lipomatous lesions with variable vascular components. Herein, we describe our single-institution experience with surgical excision of CLOVES-related truncal masses and discuss future directions in treatment of these complex anomalies. METHODS: A single-institution retrospective review was performed for patients diagnosed with CLOVES syndrome. Patients undergoing excision of truncal vascular malformations were included. Outcome measures included perioperative characteristics [estimated blood loss (EBL), specimen size/anatomic location, blood-product requirement], as well as length-of-stay [LOS], and complication profile. Mean follow-up was 23.4 months (range 4.2-44). RESULTS: Three consecutive patients were reviewed, accounting for 4 surgical operations. One patient underwent two operations for two distinct masses. All lesions were located on the upper back or flank with various degrees of muscular involvement. One patient required no transfusions with an uneventful 2-day hospitalization. The remaining three patients had an EBL ranging from 1500 to 6450 mL, requiring 9-13 units of packed red blood cells and 5-8 units of fresh frozen plasma during LOS (averaging 5 days). Mean weight of resected masses was 6.26 lbs (range 2.04-12 lbs) and mass dimensions ranged between 1778.9 and 15,680 cm3. One patient with recurrence was subsequently treated with a combination of sclerotherapy and rapamycin, leading to significant mass reduction. CONCLUSIONS: Management of CLOVES syndrome requires a collaborative and multimodal approach. Although surgical debulking is one treatment option, non-invasive medical modalities and sclerotherapy should be considered prior to surgical resection. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Wnt signaling potentiates nevogenesis.

Cellular senescence is a stable proliferation arrest associated with an altered secretory pathway (senescence-associated secretory phenotype). Cellular senescence is also a tumor suppressor mechanism, to which both proliferation arrest and senescence-associated secretory phenotype are thought to contribute. The melanocytes within benign human nevi are a paradigm for tumor-suppressive senescent cells in a premalignant neoplasm. Here a comparison of proliferating and senescent melanocytes and melanoma cell lines by RNA sequencing emphasizes the importance of senescence-associated proliferation arrest in suppression of transformation. Previous studies showed that activation of the Wnt signaling pathway can delay or bypass senescence. Consistent with this, we present evidence that repression of Wnt signaling contributes to melanocyte senescence in vitro. Surprisingly, Wnt signaling is active in many senescent human melanocytes in nevi, and this is linked to histological indicators of higher proliferative and malignant potential. In a mouse, activated Wnt signaling delays senescence-associated proliferation arrest to expand the population of senescent oncogene-expressing melanocytes. These results suggest that Wnt signaling can potentiate nevogenesis in vivo by delaying senescence. Further, we suggest that activated Wnt signaling in human nevi undermines senescence-mediated tumor suppression and enhances the probability of malignancy.

Papular Epidermal Nevus with Skyline Basal Cell Layer (PENS): Three New Cases and Review of the Literature.

BACKGROUND/OBJECTIVE: Papular epidermal nevus with skyline basal cell layer (PENS) is a recently described type of epidermal nevus with characteristic histopathologic findings, mainly regular, rectangular acanthosis and a well-demarcated basal cell layer with clear palisading and separation between basal cell nuclei and the first row of Malpighian cell nuclei. Although the first reports described randomly distributed lesions appearing sporadically in otherwise healthy patients, cases of Blaschkoid distribution, lesions associated with extracutaneous manifestations, and familial cases have been reported. METHODS: We performed a review of the clinical charts of all patients with histologic diagnosis of PENS in our hospital. We evaluated epidemiologic, clinical, and histologic features. We then reviewed the literature with a particular emphasis on the presence or absence of extra-cutaneous associations. RESULTS: Three patients with PENS are described. One had a single lesion, one had three lesions, and one, a patient with mild developmental delay, a curved penis, and hypospadias, had multiple lesions. CONCLUSION: The probability of having extracutaneous manifestations is 6.3 times as great in individuals with more than four lesions. Therefore these patients may need closer follow-up.

Quantitative Imaging In Vivo of Functioning Lymphatic Vessels Around Human Melanoma and Benign Nevi.

OBJECTIVES: The density of functioning human lymphatics in vivo and of immunohistochemically defined lymphatics was quantified around melanomas, benign nevi, and matched normal skin, to assess the current lymphangiogenesis paradigm. We investigated whether histological and functioning density increased around melanomas compared with benign nevi or matched skin; whether functioning and histological density increased similarly; and whether larger increases occurred around metastatic melanomas. METHODS: Functioning density was quantified in vivo as the total amount of human dermal microlymphatics taking up fluorescent marker injected at the lesion margin. After tissue excision, perilesion histological density was quantified using podoplanin marker D2-40. RESULTS: Histological density was raised similarly around metastasising and non-metastasising melanomas compared with normal skin (+71%, p < 0.0001, n = 32); but was also raised significantly around benign nevi (+17%, p = 0.03, n = 20). In contrast, functioning lymphatic density was substantially reduced around the margins of melanomas (both metastasising and non-metastasising) compared with benign nevi (by 65%, p = 0.02) or normal skin (by 53%, p = 0.0014). CONCLUSIONS: Raised perilesion histological lymphatic density is not unique to melanoma but occurs also around benign nevi. The findings indicated that the number of functioning lateral lymphatics around human melanomas in vivo but not benign nevi is reduced, despite histologically increased numbers of lymphatics.

Naevus sebaceus: a mosaic RASopathy.

Epidermal naevi are common cutaneous mosaic disorders that occur in 0.1-0.3% of live births. They are subdivided into keratinocytic and organoid naevi, the latter including naevus sebaceus (NS). Typically, NS develops as a yellowish-orange plaque on the scalp, and represents a hamartoma containing epidermal, sebaceous and apocrine elements. The histological features of NS sampled in childhood include hyperkeratosis, acanthosis, increased sebaceous lobules, and primitive hair follicles. During puberty, most lesions develop more prominent sebaceous and apocrine components. Subsequently, secondary tumours may occur in around 25% of NS; most lesions are benign (e.g. trichoblastomas, syringocystadenoma papilliferum or other basaloid proliferations), although malignant tumours arising within NS can occur (< 1%). Recently, somatic mosaicism has been shown, with activating Ras mutations in HRAS or KRAS in NS lesional keratinocytes (but not in adjacent nonlesional skin or dermal fibroblasts). These mutations lead to constitutive activation of the RAF-MEK-ERK and phosphoinositide 3-kinase signalling pathways, and result in increased cellular proliferation. Similar but more extensive mosaicism underlies Schimmelpenning-Feuerstein-Mims syndrome. The most common mutation is c.37G>C (p.Gly13Arg) in HRAS, which is present in > 90% of NS. This mutation also seems to be present in NS cases that develop secondary tumours, although no additional mutations (second hit) or other genetic events have yet been identified. Treatment of NS often involves prophylactic surgical excision, but the recent identification of key epidermal signalling abnormalities underlying the cell proliferation means that future development of new medical treatments for NS that target the aberrant signalling pathways may also be feasible.

Intravitreal bevacizumab for choroidal neovascularization associated with choroidal nevus.

PURPOSE: To report 10 cases of occult choroidal neovascularization (CNV) associated with choroidal nevus managed with intravitreal bevacizumab. METHODS: Interventional case series. Each nevus was examined and imaged with fluorescein angiography, B-scan ultrasonography, and optical coherence tomography. Data were retrospectively analyzed to evaluate outcomes of treatment response and visual acuity. RESULTS: Nine patients presented with CNV overlying a chronic choroidal nevus with a posterior margin within 1.5 mm of the foveola. In the 10th patient, the posterior margin of the nevus was located 10 mm from the foveola with extension of subretinal fluid into the macula. The CNV was subfoveolar in four cases, juxtafoveolar in two cases, and extrafoveolar in four cases. Initial visual acuity was 20/20 to 20/50 in 5, 20/60 to 20/100 in 2, and 20/200 or worse in 3 cases. Clinical features included subfoveolar fluid in nine, exudation in five, and hemorrhage in four cases. Intravitreal bevacizumab (1.25 mg/0.05 cc) was injected with regression of CNV in all 10 cases using 2 to 14 injections (median 3 injections). In 2 eyes, after therapeutic response to bevacizumab later consolidation with photodynamic therapy (juxtafoveolar CNV) (n = 1) or conventional laser (extrafoveolar CNV) (n = 1) was provided. In the remaining 8 eyes, after discontinuation of bevacizumab, there was no recurrence of CNV over mean 10.1 months. At overall mean follow-up of 22.5 months, final visual acuity decreased by 1 line in 4 cases and improved by mean of 3 lines (range, 1-8 lines) in 6 cases. There were no adverse effects from bevacizumab injections. All 10 choroidal nevi remained stable. CONCLUSION: Intravitreal bevacizumab appears to be an effective treatment option for CNV secondary to choroidal nevus. In some cases, depending on the proximity of the CNV to the foveola, photodynamic therapy or conventional laser may be useful adjunctive therapy.

Light scattering spectroscopy of human skin in vivo.

We present an in vivo study of the reduced scattering coefficient of normal skin and of common melanocytic nevi in Caucasian subjects. The spectral shape of the reduced scattering coefficient is described well by a power-law dependence on the wavelength, in accordance with previous studies of light scattering by biological tissues. We investigate statistical variations in the scattering spectrum slope and also identify an inherent correlation between scattering intensity and scattering spectral slope, observed mainly in normal skin. In addition, we do not find any significant differences between the scattering properties of normal skin and common melanocytic nevi. Finally, we also provide a short review of previously published studies reporting on the light scattering properties of human skin both in vivo and in vitro.

The relationship between naevus count, memory function and telomere length in the Twins UK cohort.

The presence of a skin-brain connection whereby alterations in the skin can inform on mechanisms underlying neurodegenerative diseases is increasingly recognized. In this study, we used a discovery (n = 321) and replication (n = 147) sample from the Twins UK population to test the association between naevus count and memory function, and its mediation by telomeres. Memory function was assessed in 1999 and 2009 using the paired associates learning test (PAL), while naevus count and leucocyte telomere length (LTL, assessed by the terminal restriction fragment assay) were measured once. Higher baseline naevus count was significantly associated with fewer errors at the baseline and follow-up PAL, as well as with change in PAL score over 10 years. This association was significantly attenuated after adjustment for LTL. The significant association between naevus count and PAL score was reproduced in the replication sample. These findings suggest that melanocytes might be used as model system to study the biological ageing pathways involved in neurodegeneration.

A Deep Learning Approach to Vascular Structure Segmentation in Dermoscopy Colour Images.

BACKGROUND: Atypical vascular pattern is one of the most important features by differentiating between benign and malignant pigmented skin lesions. Detection and analysis of vascular structures is a necessary initial step for skin mole assessment; it is a prerequisite step to provide an accurate outcome for the widely used 7-point checklist diagnostic algorithm. METHODS: In this research we present a fully automated machine learning approach for segmenting vascular structures in dermoscopy colour images. The U-Net architecture is based on convolutional networks and designed for fast and precise segmentation of images. After preprocessing the images are randomly divided into 146516 patches of 64 × 64 pixels each. RESULTS: On the independent validation dataset including 74 images our implemented method showed high segmentation accuracy. For the U-Net convolutional neural network, an average DSC of 0.84, sensitivity 0.85, and specificity 0.81 has been achieved. CONCLUSION: Vascular structures due to small size and similarity to other local structures create enormous difficulties during the segmentation and assessment process. The use of advanced segmentation methods like deep learning, especially convolutional neural networks, has the potential to improve the accuracy of advanced local structure detection.

Cell cycle and apoptosis regulators in Spitz nevi: comparison with melanomas and common nevi.

BACKGROUND: Deregulated cell cycle control is one of the hallmarks of tumor development. The expression of different cell cycle regulators has been used in various neoplasms as an adjunct to diagnosis. OBJECTIVE: We sough to determine the expression of cell cycle and apoptosis regulators in Spitz nevi and to appraise its value as a diagnostic adjunct in the differential diagnosis from melanomas and common nevi. METHODS: Ki-67, p-27, p-16, p-53, p-21, Rb, cyclin D1, cyclin A, cyclin B1, bcl-2, and bax expression was assessed by immunohistochemistry in 10 Spitz nevi and was compared with 16 melanomas and 20 common nevi immunohistochemical expression. RESULTS: P-27 (60% +/- 20.13), p-16 (62.00% +/- 10.85), and bcl-2 (46.00% +/- 42.47) were highly expressed in Spitz nevi, whereas Ki-67 (2.80% +/- 2.55), Rb (3.75% +/- 4.55), p-53 (2.30% +/- 0.10), cyclin A (0.70% +/- 1.56), B1 (0.20% +/- 0.34), and bax (2.65% +/- 6.37) demonstrated a limited expression. Cyclin D1 (8.60% +/- 7.30) and p-21 (6.40% +/- 5.37) showed a moderate expression. The expression of bax (P = .001), Ki-67 (P < .0001), Rb (P < .0001), p-16 (P < .0001), cyclin A (P < .0001), and cyclin B1 (P < .0001) was significantly higher in melanomas in comparison with Spitz nevi, whereas p-27 expression was significantly higher in Spitz nevi (P < .0001). A trend for significant difference in favor of melanomas was also observed for p-53 (P = .002). On the other hand, no difference was detected for bcl-2 (P = .275), p-21 (P = .055), or cyclin D1 (P = .077). Spitz nevi demonstrated a trend for a higher expression for p-21 (P = .008) and cyclin D1 (P = .006), whereas they exhibited lower p-16 (P = .004) in comparison with common nevi. LIMITATIONS: The number of Spitz nevi was relatively small. CONCLUSION: Spitz nevi differ from melanomas in their immunohistochemical pattern of expression of cell cycle and apoptosis regulators and more closely resemble common benign nevi.

Monte Carlo simulation of light-tissue interaction: three-dimensional simulation for trans-illumination-based imaging of skin lesions.

Three-dimensional, voxel-based, and wavelength-dependent skin lesion models are developed and simulated using Monte Carlo techniques. The optical geometry of the Nevoscope with trans-illumination is used in the simulations for characterizing the lesion thickness. Based on the correlation analysis between the lesion thickness and the diffuse reflectance, optical wavelengths are selected for multispectral imaging of skin lesions using the Nevoscope. Tissue optical properties reported by various researchers are compiled together to form a voxel library. Tissue models used in the simulations are developed using the voxel library which offers flexibility in updating the optical properties and adding new media types into the models independent of the Monte Carlo simulation code.

Epidermal nevus syndromes.

The term epidermal nevus syndrome (ENS) has been used to describe the association of epidermal hamartomas and extracutaneous abnormalities. Although many continue to use the term "ENS," it is now understood that this is not one disease, but rather a heterogeneous group with distinct genetic profiles defined by a common cutaneous phenotype: the presence of epidermal and adnexal hamartomas that are associated with other organ system involvement. One commonality is that epidermal nevi often follow the lines of Blaschko and it appears the more widespread the cutaneous manifestations, the greater the risk for extracutaneous manifestations. The majority of the extracutaneous manifestations involve the brain, eye, and skeletal systems. The CNS involvement is wide ranging and involves both clinical manifestations such as intellectual disability and seizures, as well as structural anomalies. Several subsets of ENS with characteristic features have been delineated including the nevus sebaceus syndrome, Proteus syndrome, CHILD syndrome, Becker's nevus syndrome, nevus comedonicus syndrome, and phakomatosis pigmentokeratotica. Advances in molecular biology have revealed that the manifestations of ENS are due to genomic mosaicism. It is likely that the varied clinical manifestations of ENS are due in great part to the functional effects of specific genetic defects. Optimal management of the patient with ENS involves an interdisciplinary approach given the potential for multisystem involvement. Of note, epidermal nevi have been associated with both benign and malignant neoplasms, and thus ongoing clinical follow-up is required.

Phenotype/genotype correlations in epidermal nevus syndrome as a neurocristopathy.

Epidermal nevus syndrome (ENS) is a term that encompasses several phenotypes defined by the association of an epidermal nevus with one or more congenital systemic anomalies, mainly ocular, osseous and cerebral. The two most frequent, keratinocytic nevus syndrome and linear sebaceous nevus syndrome, also correspond to the neurological phenotypes. They both exhibit overlapping and distinctive features but same etiology: post-zygotic mosaic mutations in RAS genes. Their pathogenesis is due to defective neural crest, further confirming that they are the same basic entity contradicting the concept that they are a group of heterogeneous syndromes with different etiologies. Both have been reported for more than a century. The sebaceous nevus, hallmark of linear sebaceous nevus syndrome, was defined by Jadassohn in 1895; the large number of subsequent contributors in defining this syndrome precludes the introduction of eponyms. Three other distinctive phenotypes within the spectrum of ENS with CNS involvement are CLOVES, SCALP and Heide's syndromes. Recognition of neurological phenotypes with multisystemic involvement should invoke multidisciplinary investigation and management. In some ENS phenotypes the association of melanocytic nevi with keratinocytic and sebaceous nevi, all sharing RAS mutations, predicts multisystemic involvement, in particular severe rickets and osseous anomalies. Phenotype is, therefore, the starting point for clinicians to guide genetic, neurological and other systemic investigations for patient management. The most frequent brain malformation in neurological phenotypes of ENS is hemimegalencephaly (HME). Epilepsy is the most frequent neurological symptom, in particular infantile spasms, with or without HME. The impact of neurological and systemic manifestations is related to onset and extent of the mutations. Timing of the mutation determines phenotype and severity. Proteus syndrome is a neurological phenotype of epidermal keratinocytic nevus syndrome not an independent, separate syndrome.

Transforming growth factor beta1 induces apoptosis in normal melanocytes but not in nevus cells grown in type I collagen gel.

We used type I collagen gel cultures to compare the growth requirements of melanocytes and dermal nevus cells. Melanocytes but not nevus cells undergo apoptosis in collagen unless supplied with growth stimulators such as fibroblast growth factor 2. To characterize the mechanism of melanocyte apoptosis in collagen, we tested the effects of transforming growth factor beta1, known to be functionally active in the skin. When picomolar amounts of transforming growth factor beta1 were added to normal melanocytes grown in type I collagen gel, their apoptosis was dramatically accelerated. In contrast, the apoptotic rate of nevus cells and melanoma cells grown under similar conditions was not affected by transforming growth factor beta1. The increased apoptosis of normal melanocytes was effectively counteracted by addition of either neutralizing transforming growth factor beta1 antibodies or fibroblast growth factor 2 to the collagen gel. Interestingly, the background apoptosis of normal melanocytes was also inhibited by transforming growth factor beta1 antibodies. By Western blotting we detected transforming growth factor beta-like immunoreactivity in melanocyte, nevus cell, and melanoma cell lysates. A sensitive bioassay confirmed that their medium contained considerable amounts of heat-activatable growth inhibitory activity that could partly be neutralized by transforming growth factor beta1 antibodies. It is evident that apoptosis of melanocytes grown in type I collagen gel can be mediated by both endogenous and exogenous transforming growth factor beta. We suggest that the balance between inhibitory growth factors such as transforming growth factor beta and stimulatory growth factors like fibroblast growth factor 2 has the potential to regulate the growth, localization, and survival of normal melanocytes also in vivo. The resistance of nevus cells to transforming-growth-factor-beta-mediated apoptosis may facilitate their ability to grow in the dermal compartment of the skin.

Transepidermal elimination of nevus cells. A possible mechanism of nevus involution.

Nevus cell nests were seen histologically within the upper levels of the epidermis in biopsy specimens obtained from three patients with clinically banal-appearing nevi. Although the presence of melanocytes arranged as solitary units or grouped in nests in the upper layers of the epidermis is one histopathologic feature of malignant melanoma, we believe this finding represents transepidermal elimination of nevus cells and may be one mechanism of nevus involution.

Corneal autofluorescence in choroidal melanoma or in choroidal naevus.

AIMS: To investigate whether corneal autofluorescence is different in patients with choroidal melanoma or choroidal naevus. METHODS: Corneal autofluorescence was determined by fluorophotometry in both eyes of 32 patients with a unilateral choroidal melanoma, 32 patients with a unilateral choroidal naevus, and 32 age matched healthy controls. The corneal autofluorescence ratio between affected and contralateral eyes of patients or between randomly selected eyes of healthy controls was calculated. RESULTS: Mean corneal autofluorescence ratio of patients with a choroidal melanoma was significantly higher than that of healthy controls (mean ratio: 1.09 (SD 0.15) and 1.00 (0.09), respectively, ANOVA p=0.014), and than that of patients with choroidal naevus (mean ratio 0.96 (0.09), p<0.001). Mean ratios of patients with choroidal naevus and healthy controls were not significantly different (p=0.27). CONCLUSIONS: Corneal autofluorescence ratio of patients with a unilateral choroidal melanoma is increased. This is probably due to an increased flow of glucose through the impaired blood-aqueous barrier in the affected eye, resulting in additional glycation of corneal proteins and hence in increased autofluorescence. The corneal autofluorescence is not increased in patients with a choroidal naevus, because the blood-aqueous barrier is not impaired in the affected eye in these patients. Measurement of corneal autofluorescence is simple, fast, and non-invasive, and might be helpful to distinguish between patients with choroidal melanoma and those with choroidal naevus.

The melanocyte and melanoma.

This paper reviewed some of the interesting biological aspects of melanocytes and their relationship to the nevus and to melanoma. It also proposed a rationale for "adequate" surgery in the management of melanoma according to level, depth, margins, and trends in treatment. These propositions were derived from an analysis of 995 cases of melanoma of the head and neck.

The lives of pigment cells.

Most pigment cells during embryogenesis arise from the cranial or truncal portion of the neural crest and migrate to the skin, hair bulbs, choroid of the eye, the inner ear, leptomeninges, and other tissues. Cells of the retinal pigment epithelium come from a different source, namely, the primitive forebrain, and are involved in the formation of the retina and the optic nerves and tracts. Most pigment cells in all parts of the body seem to be constant in number and function until approximately middle age (the fourth or fifth decade of life). Thereafter, the number of melanocytes in the skin, hair, and eyes and the number of nevi begin to decrease. One function of pigment cells may be to eradicate oxygen radicals that are responsible in part for inducing malignancies and are also involved in the aging process. Possibly one result of the loss of melanocytes from the various organs is acceleration of the aging process in a permissive environment for the development of malignancies.