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It has been proposed that all nevi reflect mosaicism, and this concept has been corroborated at the molecular level in a number of nevi. If the concept of mosaicism holds true, one would expect that the various types of nevi should be characterized by intrinsic shapes or patterns. A photographic review of 1,188 recognizable images of a list of nevi of the skin was undertaken in order to delineate a classification of the various shapes and patterns of nevi. We disclosed three distinct shapes and two so far undescribed archetypical patterns, in addition to the well-known Blaschko-linear, flag-like and extensive garment-like patterns, to which all lesions could be allocated. The newly delineated shapes are called round or oval shape; patches with indented borders; and teardrop or triangular shape. The newly proposed archetypical configurations are the agminated pattern and the diffuse patchy pattern. Other mosaic patterns, such as the phylloid pattern or the lateralization pattern, were not observed in any of the images reviewed. We conclude that the various types of nevi can be assigned to specific shapes or patterns. Admittedly, however, a given nevus may manifest itself in several different shapes, whereas its archetypical pattern tends to be the same. This 'archetypical' pattern can be taken as the perfect or ideal model of a given type of nevus, whereas the newly described shapes are subordinated to the archetypical patterns and are best considered to be 'nonarchetypical'. Our work gives more consistency to the idea that nevi reflect mosaicism, because they display repetitive shapes and patterns.

It has been hypothesized that cutaneous melanoma at different anatomic sites develops through divergent pathways. We examined this hypothesis prospectively. We followed 152,949 women and 25,204 men free of cancer at baseline for up to 14 years in three large prospective studies. We examined risk factors for melanoma by anatomic location (head or neck, trunk, upper extremity, and lower extremity). Polytomous logistic regression was used to test the difference among risk factors by location of melanoma. A total of 511 incident cases of invasive melanoma (49 head or neck, 188 trunk, 98 upper extremity, and 176 lower extremity) were included in the analysis. Compared with females, males had a higher risk of developing melanoma on the head or neck and trunk. History of severe and painful sunburn was most strongly related to melanoma of upper extremity; individuals with >10 burns had a 6.86-fold (95% confidence interval, 2.62-18.00) higher risk of melanoma of upper extremity compared with those with no burns (P for trend < 0.0001; P for difference by body site = 0.04). Number of moles was most strongly related to melanoma of the trunk; the multivariate relative risk for having >10 moles was 4.67 (95% confidence interval, 3.07-7.11) compared with having no moles (P for trend < 0.0001; P for difference by body site = 0.04). Age, family history of melanoma, and hair color did not statistically differ by anatomic site of the cancer. These data support divergent etiologic pathways of melanoma development by anatomic sites.

Background: Nevi on certain areas of the body such as the acral, genital, and flexural regions may exhibit uncommon but characteristic histopathologic features. The purpose of this study was to characterize the distinctive features of nevi with a junctional component located on and around the ear., Materials and Methods: A total of 101 compound and junctional nevi of the ear received at the Yale Dermatopathology Laboratory during a 10-year period were examined in this study. The most characteristic feature of the majority of these nevi was irregularity of nesting pattern, with nests, which varied in size and shape and which were sometimes located between rete ridges., Results: Forty-two (42%) of nevi on and around the ear showed poor circumscription, lateral extension of the junctional component beyond the dermal component, and elongation of rete ridges with bridging between them. A subset of these nevi (26 cases) showed uniformly large melanocytes with large vesicular nuclei without prominent nucleoli, and abundant pale, finely granular cytoplasm. These lesions did not show a tendency to recur., Conclusions: This study supports the existence of a subset of nevi on or near the ear that, like certain nevi located on other special sites, exhibit unusual but characteristic features, which may be misinterpreted as atypical or malignant.

Electrical bio-impedance can be used to assess skin cancers and other cutaneous lesions. The aim of this study was to distinguish skin cancer from benign nevi using multifrequency impedance spectra. Electrical impedance spectra of about 100 skin cancers and 511 benign nevi were measured. Impedance of reference skin was measured ipsi-laterally to the lesions. The impedance relation between lesion and reference skin was used to distinguish the cancers from the nevi. It was found that it is possible to separate malignant melanoma from benign nevi with 75% specificity at 100% sensitivity, and to distinguish nonmelanoma skin cancer from benign nevi with 87% specificity at 100% sensitivity. The power of skin cancer detection using electrical impedance is as good as, or better than, conventional visual screening made by general practitioners.

Background/purpose: The observation that skin pattern tends to be disrupted by malignant but not by benign skin lesions suggests that measurements of skin pattern disruption on simply captured white light optical clinical (WLC) skin images could be a useful contribution to a diagnostic feature set. Previous work which generated a flow field of skin pattern using a measurement of local line direction and variation determined by the minimum eigenvalue and its corresponding eigenvector of the local tensor matrix to measure skin pattern disruption was computationally low cost and encouraging. This paper explores the possibility of extracting new features from the first and second differentiations of this flow field to enhance classification performance., Methods: The skin pattern was extracted from WLC skin images by high-pass filtering. The skin line direction was estimated using a local image gradient matrix to produce a flow field of skin pattern. Divergence, curl, mean and Gaussian curvatures of this flow field were computed from the first and second differentiations of this flow field. The difference of these measures combined with skin line direction across the lesion image boundary was used as a lesion classifier., Results: A set of images of malignant melanoma and benign naevi were analysed as above and the scatter plot in a two-dimensional dominant feature space using principal component analysis showed excellent separation of benign and malignant lesions. A receiver operating characteristic plot enclosed an area of 0.96., Conclusions: The experimental results show that the divergence, curl, mean and Gaussian curvatures of the flow field can increase lesion classifier accuracy. Combined with skin line direction they are promising features for distinguishing malignant melanoma from benign lesions and the methods used are computationally efficient which is important if their use is to be considered in clinical practice.

Minimal deviation melanoma is a controversial entity encompassing a heterogeneous group of lesions cytologically in the spectrum between recognized subtypes of nevi and conventional "primary configuration" melanomas and reported to have a better prognosis than the latter. To evaluate the distinctiveness of minimal deviation melanoma, Ki-67 proliferation rates and p53 expression in minimal deviation melanomas were compared with those in compound nevi, Spitz nevi, and vertical growth phase superficial spreading malignant melanoma. Twelve examples of each lesion were immunostained with antibodies to the Ki-67 and p53 proteins and evaluated by a pathologist who was blind to the diagnoses. The mean Ki-67 (MIB-1) proliferation rates for the compound nevi, Spitz nevi, minimal deviation melanomas, and superficial spreading malignant melanomas were 0, 3%, 13%, and 25%, respectively. The mean Ki-67 proliferation rate was statistically greater in the minimal deviation melanomas than in the compound nevi or the Spitz nevi (P <.05), but the proliferation rates in the two melanoma subtypes were not statistically significant (P =.08). The mean p53 values for these lesions were 0, 9%, 9%, and 26%, respectively; the latter two were statistically different (P <.01). Based on these Ki-67 and p53 immunophenotypes, minimal deviation melanoma may represent a distinct entity.

Background: Atypical melanocytic nevi and cutaneous melanoma are often marked by variation in color. However, there are examples of "benign" explanations for irregularities in pigmentation, such as perifollicular hypopigmentation or hyperpigmentation., Objective: The purpose of this study was to correlate the clinical and histologic features of 3 unusual melanocytic nevi consisting exclusively of multiple, tiny, dark brown to black dots on a skin-colored background, which we have termed pointillist nevi., Methods: Histologic examination was performed of the single pointillist nevus from each of 3 patients (all women; aged 28, 39, and 47 years)., Results: The diameters of the pointillist nevi were 2, 3.5, and 5.5 mm. Individual dots were approximately 0.1-0.25 mm. Each of the 3 nevi showed a different histologic correlate for the dots, either (1) discrete, densely pigmented, junctional melanocytic nests; (2) isolated dermal pigmented melanocytic nests; or (3) discrete clusters of melanophages in the papillary dermis., Conclusion: Pointillist nevi are benign melanocytic nevi with histologic correlates similar to those of the "brown globules" observed by dermoscopy in uniformly pigmented nevi. However, the dots seen in pointillist nevi can be visualized without magnification. The clinical and histologic features of pointillist nevi add to the spectrum of unusual patterns of pigmentation that may be encountered in benign melanocytic lesions.

Introduction: We have carried out a retrospective study of 135 patients followed at Curie Institute for choroidal naevus between March 1983 and June 1997., Patients and Methods: 54 patients presented naevi considered as benign and 81 patients presented suspicious choroidal naevi (with at least one of the following findings: visual symptoms; serious detachment of the retina; orange pigment; thickness greater than 2mm or a diameter greater than 7mm). These suspicious naevi were followed more carefully. The median follow-up was 49 months. The median diameter of the lesions was 6mm and the median thickness was 1.5mm. We studied the age of the patients, clinical symptoms, the presence or absence of orange pigment, drusen and serious detachment, and the angiographic and echographic findings., Results: 3 patients died of unrelated cause; 7 patients were lost to follow-up; 30 patients presented documented growth; 4 of them belonged to the group considered as benign and 26 to the group considered as suspicious, with a significant difference between the groups. The lesions that grew were treated by proton beam or I125 patches. The risk factors for growth that were statistically significant were the presence of visual symptoms, pin points, orange pigment, serous detachment and thickness greater than 2mm. With drusen, the risk for growth was significantly less., Discussion: These results are very similar to those published in the literature concerning risk factors for growth of choroidal nevi. The absence of metastatic spread in patients whose nevi have grown show that it is possible to monitor choroidal naevi if there is a doubt as to the malignant or benign nature of the lesion., Conclusion: It is important to determine if a choroidal naevus is suspicious or benign and to propose closer follow-up for suspicious lesions.

To develop a noninvasive, early-detection method for skin cancers, a feasibility study of multispectral image analysis was investigated. The three most frequently occurring skin cancer types, ten basal-cell carcinomas (BCCs), ten squamous-cell carcinomas (SCCs) and five malignant melanomas (MMs) were studied, along with ten normal moles. Images were acquired by a charge-coupled device camera using eight narrow-band filters ranging from 450 nm to 800 nm, at 50-nm intervals. To extract main features of these tumors, principal components analysis (PCA) was performed, because it projects the multidimensional (here, eight-dimensional) data in the direction of maximum data variance. Then, the primary PCA components for red, green, and blue subset images were analyzed in terms of hue-saturation-intensity (HSI). By hue distributions, the BCCs and SCCs were differentiated from the MMs and normal moles. Texture information was used to further classify tumor types after the HSI analysis. The texture analysis, performed using a spatial gray-level co-occurrence matrix (SGCM), could separate MMs from normal moles. The BCCs and SCCs were further studied by Fisher's linear discriminant analysis. Distribution was described as a Gaussian mixture model. By this classification procedure, seven BCCs, eight SCCs, five MMs, and ten NMs were correctly classified. Three BCCs and two SCCs were unseparable. Thus, multispectral skin cancer image analysis has potential to diagnose skin cancers.

The melanoma epidemic in adults is well documented, and there is now evidence that the incidence of malignant melanoma in teenagers is increasing. Risk factors for melanoma are recognizable in children and include congenital nevi, numerous common nevi, and atypical nevi. Large congenital nevi overlying the head or spine also carry risk for central nervous system involvement, which, if symptomatic, carries a grave prognosis. Laser therapy has recently been advocated for small congenital nevi but often yields only temporary improvement. Adjuvant therapy with interferon alfa-2b holds promise for patients with metastatic melanoma. Melanoma risk is also linked to sun sensitivity and childhood exposures, and sunscreen use has been promoted for prevention of skin cancer. Because many sunscreens offer protection from ultraviolet (UV) B but not UVA, spectra that may be involved in melanoma induction, pediatricians should counsel their families to practice a full program of sun protection that includes sun avoidance and protective clothing and eyeware in addition to sunscreens.

A significant proportion of cutaneous malignancies arise from well-defined precursor lesions that have often been present for many years. This provides an opportunity to reduce rates of skin cancer by recognition and treatment of these lesions. Precursors of keratinocytic malignancy, such as actinic keratoses and Bowen's disease, are extremely common in the older, white population and will frequently be encountered by generalist physicians in the context of examinations for noncutaneous conditions. Less common conditions, such as erythroplasia of Queyrat and nevus sebaceous, are associated with a higher risk of malignant change, and their recognition is therefore imperative. The management of the various precursors of melanoma remains controversial, as the exact risk of malignant transformation of many of these lesions is still unclear.

Background: Encephalocraniocutaneous lipomatosis is usually associated with a peculiar type of fatty tissue nevus which represents a smoothly surfaced and hairless lesion involving the scalp. This disorder has so far not been recognized as a cutaneous entity., Objective: The purpose of this article is to describe the characteristic features of this nevus and to give it a name., Method: From the study of two cases and from a review of the literature we delineate the clinical and histopathological criteria of this disorder for which we propose the term 'nevus psiloliparus'. This name is derived from the Greek words psilós = hairless and liparós = fatty, and describes the two most characteristic features of the disorder., Results: A comprehensive comparison shows that nevus psiloliparus can be distinguished from other types of fatty tissue nevi by clinical criteria such as localization on the scalp, a flat smooth surface and absence of hair follicles, by the histopathological feature of isolated arrector pili muscles and by the presence of associated extracutaneous features in the form of encephalocraniocutaneous lipomatosis. In particular, nevus psiloliparus can be separated from the Hoffmann-Zurhelle nevus that has so far never been observed in cases of encephalocraniocutaneous lipomatosis., Conclusion: The presently available data suggest that nevus psiloliparus represents a distinct cutaneous entity. Future clinical and genetic research should show whether this concept holds true.

The current classification of malignant melanomas gives recognition to superficial spreading melanoma, lentigo maligna melanoma, acral lentiginous melanoma, and nodular types. In addition, neurotropic and desmoplastic types are recognized. The relativity inherent in the diagnosis of melanoma, provides the basis for the classification of melanomas on the basis of size. Lesions measuring 1 mm or less in vertical dimensions are unlikely to metastasize; they qualify as borderline melanocytic neoplasia of indeterminant malignant potential. The current classification has little relevancy to the category of variant nevi with the exceptions of malignant cellular blue nevus and melanoma arising in giant congenital nevi. A classification of variant melanomas as related to variant nevi is proposed. From a different perspective, a classification of melanomas with attention to nesting and cytological patterns in vertical growth is proposed: this alternate approach gives recognition to lesions that might otherwise be classified as "nevoid" melanomas. It also provides a default category for lesions that might otherwise be assigned to the Spitz nevus-like category. All of these tools for the manipulation of the real and virtual images of melanomas have been emphasized in the concept of minimal deviation melanoma.

Objective: To investigate the relationship of number and type of nevi to the development of melanoma., Design: Case-control study., Setting: Outpatient clinics in referral hospitals., Patients: Cases were 716 consecutive patients with newly diagnosed melanoma identified at 2 melanoma centers between January 1, 1991, and December 31, 1992. Stratified random sampling of patients from outpatient clinics was used to identify 1014 participating controls of the same age, sex, race, and geographic distribution as the melanoma cases. All study subjects underwent an interview, a complete skin examination, photography of the most atypical nevi, and, if the patient was willing, a biopsy of the most atypical nevus., Main Outcome Measures: Number and type of nevi on the entire body were systematically reported. All diagnoses of clinically dysplastic nevi were confirmed by expert examiners., Results: Risk for melanoma was strongly related to number of small nevi, large nondysplastic nevi, and clinically dysplastic nevi. In the absence of dysplastic nevi, increased numbers of small nevi were associated with an approximately 2-fold risk, and increased numbers of both small and large nondysplastic nevi were associated with a 4-fold risk. One clinically dysplastic nevus was associated with a 2-fold risk (95% confidence interval, 1.4-3.6), while 10 or more conferred a 12-fold increased risk (95% confidence interval, 4.4-31). Congenital nevi were not associated with increased risk of melanoma., Conclusions: Although nondysplastic nevi confer a small risk, clinically dysplastic nevi confer substantial risk for melanoma. On the basis of nevus number and type, clinicians can identify a population at high risk of this epidemic cancer for screening and intervention.

In 1975, Mehregan et al (1) proposed the term pedunculated lipofibroma for the solitary form of NLCS in the view of its distinctive clinicopathologic features. Subsequently, Nogita et al reported and reviewed 32 cases of pedunculated lipofibroma in 1994. Pedunculated lipofibroma is a relatively rare form of benign connective tissue proliferation abnormality characterized by ectopic adipose tissue in the dermis. We observed a case of pedunculated lipofibroma with a prominent stalk containing feeding vessels, a history of congenital onset, a remarkable globular apple-shaped mass and an accompanying small sessile lesion. We report this case with a review of the literature.

From the study of standard textbooks of dermatology, no comprehensive understanding of the word nevus can be derived. The purpose of this article is to formulate a workable definition. As a first step, various definitions proposed by previous authors are reviewed. Their inconsistency appears to be mainly due to the fact that the term nevus is used to denote both neoplastic and nonneoplastic, congenital and acquired as well as hereditary and nonhereditary skin lesions. Taking this difficulty into account, the author suggests, as a unifying concept, the new category of genetic mosaicism. The following definition is proposed: 'Nevi are visible, circumscribed, long-lasting lesions of the skin or the neighboring mucosa, reflecting genetic mosaicism. With the exception of melanocytic nevi, they do not show neoplastic growth. They never show malignant neoplasia.'--For several types of nevi the concept of genetic mosaicism has already been confirmed at the cellular level. Future cytogenetic and molecular studies should show whether the proposed definition is valid for all other types of nevi and thus generally acceptable.

The recognition of dysplastic nevi from photographs can aid in population surveys of nevi and in epidemiological studies of melanoma risk. The reproducibility of techniques for recognizing nevi as dysplastic or for scoring them according to the degree of dysplasia has not been measured. Using photographs of 300 nevi taken in the course of a case-control study of melanoma, we assessed the agreement among six clinicians in independently categorizing nevi as dysplastic and in grading the degree of dysplasia. On average, reviewers agreed with each other 77% of the time in classifying a nevus as dysplastic or normal. Pairwise agreement within one point on a six-point scale occurred 87% of the time on average. These results suggest that criteria for recognizing nevi as clinically dysplastic from photographs can be applied reproducibility.

Successful management of the pediatric patient is a challenge to plastic surgery nurses as they work in tandem with surgeons to guide the family through the treatment process. This article will discuss the treatment of a number of congenital birthmarks, specifically congenital vascular birthmarks and congenital nevi, which have a potential for malignant transformation.

Cutaneous nevi are common lesions that develop by proliferation of melanocyte-derived cells. The majority develop as junction nevi from melanocytes at the epidermo-dermal junction. Cells from this proliferation pass into the underlying dermis forming compound nevi. Later junctional melanocytic activity ceases, leaving an intradermal nevus. A minority of nevi, mainly blue nevi, arise from intradermal melanocytes. Histological variants of melanocytic nevi exist and can be the source of difficult diagnostic problems. Nevi are important as clinical and histological simulators of cutaneous melanoma, as precursor lesions for melanoma (although the actual chance of malignant transformation of an individual nevus is low) and as cosmetic problems (mainly large congenital nevi). Cutaneous nevi are to be separated clinically and histologically from melanomas that are comprised of nevocyte-like cells (minimal deviation melanoma).

We present a morphometric method aimed at evaluating the growth of pigmented naevi. The index of clinical atypia includes evaluation of area and corrugation of the lesions. The index of evolutivity compares the indices of clinical atypia at intervals of 100 days. The indices differ with the pathologies and also with each naevus in each group. Arranging the clinical atypia and evolutivity indices in decreasing values enabled us to distinguish between naevi under the influence of human growth hormone (hormonal influence), naevi intensively and recently sun-irradiated (UV influence) and unstimulated naevi of normal subjects.

Twenty-one intradermal nevi were studied by morphometric methods in an attempt to morphologically characterize the two types of nevus cell--epithelioids, type A, and fusiforms, type C--and to quantify the differences between them. Morphometric parameters of the intradermal nevi were compared with similar parameters of melanocytes and melanoma cells so that the maturation rates of the nevi cells could be established and to see if the parameters might indicate the degree of malignancy. Superficial nevus cells were differentiated from deep cells by their larger size and larger nuclear area. Nuclear area appeared to have potential for differentiating benign from malignant tumors. Decrease in cellular area appeared to indicate maturation rather than atrophy. Melanoma cells were differentiated by their larger size. Cell nuclear perimeter appeared to have confirmatory value, while cell perimeter was inconclusive.

Many epidermal naevi with the histology of Darier's disease have been reported. In the absence of associated features of Darier's disease, they cannot be assumed to have a common pathogenesis with it, and it has been suggested that they are better classified as acantholytic dyskeratotic epidermal naevi rather than naevoid Darier's disease. We describe a patient with such a naevus who had typical nail and palmar changes of Darier's disease on the same side of the body. We suggest that in at least some cases the naevus has the same genetic defect(s) as generalized Darier's disease, and discuss the possibility that a patient with such a naevus could occasionally transmit Darier's disease to an offspring.

Prompted by the well-known difficulties of reliable and objective histologic differentiation between initial malignant melanoma (MM) and benign nevocytic nevi (NN), ultrastructural high-resolution image and multivariate analyses were evaluated for their diagnostic efficiency. Thirty-seven different features describing morphometry (area, circumference, and shape factor), amount of heterochromatin and euchromatin, chromatin homogeneity, and presence of smaller dark chromatin aggregations were determined by a MICROVAX 3500 computer in each of 1840 intraepidermal melanocytic nuclei of 17 MM and 20 NN. A strategy for the classification of cases based on the identification of markedly atypical melanocytic cells (MACS) was developed. MACS, selected in multivariate analysis with a linear combination of the eight most important features for cell classification, were found in 39.4% of the melanoma cells, but only in 0.3% of nevocytic nevus cells. The presence of MACS allowed a clear differentiation between MM and NN. All cases of MM had more than four MACS, whereas 17 cases of nevocytic nevi were MACS negative, and in each of the remaining three cases only one MAC was present. The percentage of MACS detected within intraepidermal parts of MM by using computerized high-resolution image analysis was found to be a highly efficient diagnostic marker. The new classification strategy has the potential of saving considerable time in subsequent studies, because preselected sampling and the calculation of only a few criteria have proven sufficient for correct classification of malignant melanomas.

The term epidermal nevus syndrome is not suitable to describe an entity because there are different birth defects associated with epidermal nevi. A new classification is proposed to distinguish three well-defined syndromes, each recognizable by a different type of nevus. The sebaceous nevus syndrome and the Proteus syndrome are most likely due to autosomal lethal mutations and therefore always occur sporadically, whereas the CHILD syndrome can be transmitted from a mother to her daughter as an X-linked dominant, male-lethal trait. Moreover, the nevus comedonicus syndrome can be regarded as an entity closely related to this group of disorders. It may represent another autosomal lethal mutation that survives by mosaicism. In addition, several less well-defined phenotypes associated with epidermal nevi are reviewed. Some of them are regarded as entities in limbo.

Silver staining of nucleolar organizer regions is an objective method for evaluating the malignancy of a variety of tumors. We studied 126 ciliochoroidal melanomas, three coincidental nevi that occurred in eyes with melanomas, and one magnocellular nevus collected from the Collaborative Ocular Melanoma Study to determine the effectiveness of the silver-stained nucleolar organizer region technique in assessing the malignant potential of these tumors. Malignant lesions demonstrated higher mean silver-stained nucleolar organizer region counts (4.347) than benign nevi (1.855) (P less than or equal to .0001). Among malignant melanomas, mixed-cell melanomas had slightly higher counts than spindle-cell melanomas (P less than or equal to .0001), but this difference was not important clinically. Results were also compared to other histopathologic variables, which disclosed correlation of silver-stained nucleolar organizer regions with mitoses and tumor size. Comparison with computerized cytomorphometric analyses of prognosis also disclosed significant correlation. This technique may prove to be a useful adjunct in the assessment of malignancy and treatment response of uveal melanomas.

Can the genetic concept of somatic recombination explain the phenomenon of vascular twin naevi in man? If so, this cutaneous disease would be a human counterpart of twin spots observed in animals and plants.

Although the term "nevus cell" was introduced nearly a century ago and is used daily in the parlance of general pathology and dermatopathology, writings about the subject indicate that agreement has yet to be reached about the nature of these cells. On the basis of all of the evidence about "nevus cells," morphological and biochemical, that has been accumulated to date, we conclude that they are simply melanocytes.

Investigations by use of the formaldehyde-induced fluorescence (FIF) method in benign and malignant pigment tumors of the skin are the main basis of the present monograph concerning the theory of the dualistic histogenesis of melanoma according to Mishima. Furthermore, the value of the FIF method in both classification and diagnosis of pigment-producing tumor cells after certain forms of therapy is emphasized. Experimental studies with nevus cell nevi have gained important findings on the histogenesis of nevus cells. These results indicate that nevus cells are possibly derivatives of normal melanocytes, for nevus cells in junctional nests still show a dendritic pattern like melanocytes. Based on photocatamnestic studies it can be concluded that the initial growth of melanoma may be very protracted. There are many indications that pigment spots which had sometimes existed for decades and were mistaken for nevi were malignant from the very beginning and had developed from the melanocytes of the epidermis. The development of melanomas on nevus cell nevi seems to be an exception. However, in these cases, too, malignant transformation occurs in the melanocytes of the epidermis overlying the nevus rather than in the nevus cells. This is confirmed by the findings obtained by the FIF method; under certain conditions dendritic cells may be demonstrated in all types of melanoma, which gives support to the unitary melanocytogenic origin of the tumor. However, typical dendritic tumor cells in great numbers are only visible in lentigo maligna. In the other tumors (e.g., SSM or NM), the shape of the tumor cells and the growth of the melanoma are probably dependent on the varying degree of cell dedifferentiation, the ability or unability for horizontal spreading growth as well as on terrain factors. However, there is every reason to believe that melanoma cells originate from melanocytes of the skin (or mucous membranes).

Numerous vascular dysplasiae belong to the group of genodysplasiae. Most arteriovenous dysplasiae (cirsoid, racemosum aneurysms,...) are the substratum of various regional "angiomatosis". Stenotic or ectatic arterial dysplasiae can be associated with genodysplasiae. In addition, lymphatic dysplasiae (congenital elephantiasis, etc...) also exist. Among benign tumours, angiomas are sometimes hardly distinguishable from dysplasiae. Some tumors with intermediate malignancy have an uncertain prognosis: chemodectoma, hemangiopericytoma. As for malignant vascular tumours, they fall into 3 varieties: angiosarcoma, Kaposi's sarcoma and sarcoma of vascular walls.

A comparison of clinical statements and histologic findings reveals a lower diagnostic success in angiomas, compared with other benign tumours. Cavernous forms of angiomas are very often not discerned. Capillary angiomas are misdiagnosed as cavernous ones, and teleangiectatic nevi as angiomas. Mistakes and their incidences are pointing not at real difficulties of differentialdiagnosis, but at wrong information of physicians as to the cause of errors. According to this supposition, a great part of textbooks in different medical disciplines offer no correct representation of this object. Our results reveal problems concerning the representation of some aspects of skin diseases outside of Dermatology. The diagnosis of angiomas, with special regard to the therapeutic consequences of the fundamental distinction of angiomas from angiectatic nevi by proliferation of endothelial cells, and of cavernous from capillary angiomas by vascular structure imitating arteries or veins, demands more attention in medical education.

An unselected cohort of 4,641 newborns was ascertained prospectively for the purpose of detecting any cutaneous lesion. These were catalogued into pigmented lesions, vascular lesions, and miscellaneous lesions. Several important findings were elucidated: congenital nevocellular nevi are speckled at their borders; no white newborn in the study had more than one café au lait mark; a hypopigmented tuft of hair was seen in one infant with tuberous sclerosis but is found more commonly in normal individuals; a previously undescribed lesion called zosteriform melanocytic nevus was seen as a normal pigmentary variant in blacks; and hypopigmented macules seen at birth are seen primarily in normal infants. It is hoped that these findings will allow the pediatrician and dermatologist to offer more meaningful prognostic information to their patients.

In recent years several investigators have reached the conclusion that the prognosis of melanoma of the iris is related to the cell type of the tumor. Overall mortality ranges from 3.0-3.6%, but there is no correlation between the clinical manifestation of the tumor, its microscopic appearance, or the results of angiography. The clinical behavior of histologically benign tumors may be malignant, with penetration through the trabeculum into the ciliary body and sclera, and there may even be recurrence following excision of the tumor. We present 2 women, 20 and 59 years old, respectively, with melanoma of the iris with malignant behavior. However, in 1 of them the microscopic picture was completely benign, although the tumor had penetrated into the angle of the anterior chamber and had caused severe secondary glaucoma.