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Histiocytes belong to distinct groups of cells. Similarly, histiocytoses represent some pathologic expressions of the various histiocyte lineages recognized by their distinct phenotypes. The recognition of four major histiocytosis types relies on the distinction between monocytes-macrophages, dermal dendrocytes, Langerhans cells and the so-called indeterminate cells. Each of these groups exhibits a distinctive clinical and histological presentation. The risk of internal involvement, the prognosis and therapy are different as well. The diagnostic mainly relies on the clinico-pathologic assessment, and more particularly on the combination of histological, immunohistochemical and ultrastructural examinations.

Cutaneous cystic-like lesions do not always correspond to real epithelial cysts. Indeed, the histological examination may identify another benign tumour. But, in some instances, the surprise may be greater. We report three patients in whom lesions suggested clinically small cysts. However, they were malignant neoplasms corresponding to a malignant fibrous histiocytoma, an epithelioid angiosarcoma and a metastatic adenocarcinoma, respectively.

Acanthosis nigricans in obese adolescents is frequently associated with hyperinsulinemia and insulin resistance. We report three cases of this condition. In the early stage the skin lesions appeared to be erythematous and pruritic, mimicking an inflammatory dermatitis. Dietary control and oral metformin hydrochloride markedly improved the lesions. Topical calcipotriol may also help to control the skin condition.

The Ehlers-Danlos syndrome (EDS) represents a heterogeneous group of connective tissue disorders recognized by distinct clinical, microscopic, and biochemical aspects. In particular, some histologic and ultrastructural clues have been reported in the literature. We present a novel immunohistochemical aid to the diagnosis of the most frequent type of EDS. Factor XIIIa-positive dendrocytes are almost absent in the reticular dermis and markedly reduced in number and size in the adventitial dermis. By contrast, the densities of vimentin-positive cells and CD34-positive cells were unremarkable. The biologic significance of this finding is unknown. However, at least a subset of dermal dendrocytes interacts with fibroblasts. This mechanism could be affected in the classic form of EDS.

Background/aims: Narrow-band spectrophotometry that yields melanin (M) and erythema (E) indexes is a convenient method for assessing skin colour. The objective of the study was to assess the phenotype-associated body site differences in skin complexion., Method: The Mexameter MX16 was used to record the skin colour in 137 subjects. Evaluations were made on the inner arm, volar forearm, dorsal forearm and forehead., Results: The inner arm and volar forearm had similar values for each of the colorimetric values. The dorsal forearm exhibited the highest M values, and the forehead had the highest E values. Significant positive linear correlations were found between M values from the distinct body sites. The E values showed a correlation only between the inner arm and the volar forearm., Conclusion: Regional skin colour differences are obvious. Sun-exposed skin does not react in the same way on the forearm and forehead. Regional variations in M can be predicted from the innate M value. In contrast, the regional variability in E is highly variable among subjects.

The frequent practice of a music instrument represents a risk for frictional or allergic contact dermatitis. The localisation and type of lesions are often typical for the musician specialty.

Ultrastructural examination of the skin plays an important role in the diagnosis of some cutaneous and neurologic diseases such as ichthyoses, inherited connective tissue syndromes, non-X histiocytoses, anaplastic tumors, storage disorders, mitochondrial and degenerative neuropathies, POEMS, CADASIL.

Stealthy arthropods perpetrate their insults to humans through three distinct mechanisms including bites, stings or simple contact with the skin. The present review is a summary of the bite effects of spiders and diptera.

In opposition to intuitive and empirical approaches, rigorous medicine relies on two axes of development. Evidence-Based Medicine is currently put forward. However, it can not replace rational medicine rooted in physiopathological explanations. Dermatology does not escape such conceptual duality. Dermatopathology is one major pillar of rational dermatology. Such situation is jeopardized by health planners who deny the perennial skill of dermatologists and concede hegemony of dermatopathology to general pathologists.

The clinical diagnosis and treatment of cutaneous cancers represent a frequent situation in cancerology. About one third of all human cancers take their origin from the skin. The general practitioner and the dermatologist-oncologist play the key role in that field of health care.

Several recent epidemiological and biological studies suggest that polyphenols contained in tea exhibit anticarcinogenic effects. The present review is a synthesis of the current information.

We report on a child with a generalized skin disorder associated with other minor anomalies. At birth, the child presented as a collodion baby, with patchy erythema, generalized irregular dermal atrophy, alopecia, absent eyelashes and eyebrows, and conjunctival pannus. He also had hypertelorism, prominent nasal root, large mouth, micrognathia, brachydactyly, syndactyly involving all interdigital spaces, and camptodactyly of fingers III-V. The hyperkeratotic membrane thinned progressively, leaving a mottled reticulated skin atrophy, with patchy areas of yellowish hyperpigmentation and papyraceous areas. Hair and nails were dystrophic. Mental development was borderline normal. The histological hallmarks of the skin manifestations combined orthokeratotic hyperkeratosis and marked atrophy of the dermis. The dermal extracellular matrix was immature, and factor XIII-a positive dendrocytes were rare and globular rather than dendritic. We frame as a hypothesis that the disease is due to or associated with a defect in maturation of a subset of dermal dendrocytes during fetal life. This entity may be designed as the koraxitrachitic syndrome (kappaomicronrhoalphaxi:grapnel- taurhoalphachiiotatauepsilonsigma: roughness), (Copyright 1999 Wiley-Liss, Inc.)

Dioxin is the common name for a series of 75 dibenzodioxins, 135 dibenzofurans and 209 PCBs. Among these chemicals, less than 30 prove to be toxic. Those molecules can act as hormone disrupters, suppress the immune system, alter the physiology of the sebaceus follicle and participate in the carcinogenesis of sacromas, lymphomas and some carcinomas. They may be responsible for some birth defects. In some regions of the world, dioxins and dioxin-like chemicals are present in the environment, the food chain and body tissues at doses at or near at the level supposed to cause harm to public health.

The Mosan Study Group of Pigmented Neoplasms was founded about 15 years ago. It has collected more than 20,000 cutaneous malignancies including melanomas and basal and squamous cell carcinomas. The incidence of these cancers is on the rise in Wallonia. In particular, malignant melanomas represent a spectrum of emerging cancers characterized by a proteiform biological outcome. They mostly affect young women. The major risk factor appears to be iterative and unwise ultraviolet exposures. The prevention of melanomas is basically founded on such a dogma and accordingly relies on sunscreens. However, controversies about their beneficial effects are rife and fueled by axiomas and contradictory sophisms. At the exception of surgery, the therapeutic options for the diverse types of melanomas do not yet fulfill the scope of evidence-based medicine.

Several diseases of the nipple and areola have a specific dermatological presentation. They may be classified into five main categories including dysembryoplasias, mastalgia, inflammatory dermatoses, hyperkeratoses and neoplasms.

Hormonal modifications associated with pregnancy induce some physiopathological changes in the skin. The main alterations occur in the pigmentary and vascular systems. Other changes affect the dermis, hair growth and the sebaceous gland activity. Some infectious and auto-immune dermatoses are influenced by pregnancy and vice versa. Various dermatological treatments have a negative impact on the foetus. In addition, there exists a small number of specific dermatoses of pregnancy.

Introduction: The subacute necrotizing histiocytic lymphadenitis was reported for the first time in 1972 in Japan by Kikuchi and by Fujimoto and his colleagues. This idiopathic disease can affect the skin. We report a case of Kikuchi-Fujimoto disease with skin and lymph node involvement., Observation: The Yemani man developed cervical lymphadenitis and arciform papulo-nodular lesions of the face. The histologic examination revealed a necrotizing lymphadenitis with blast cells but devoid of neutrophils. The cutaneous involvement corresponded to an angiocentric infiltration by mononuclear cells among which plasmacytoid cells and caryorrhexis were recognized. A spontaneous resolution of the disease occurred spontaneously within three months., Commentary: The clinical and histologic aspects of the present case resemble in part the presentation of lupus erythematosus. However, some distinctive features suggest Kikuchi-Fujimoto disease cannot be termed a classical type of lupus erythematosus.

Pets like dogs and cats are responsible for a series of zoonotic disorders. Some of these diseases are inflicted by bites, scratches or licking. Others result from a close contact with fur, or are transmitted by ectoparasites or by the contaminated environment. Some systemic infectious and parasitic diseases are transmitted from animals to humans and vice versa. Such situation may lead to endemic problems in some communities.

Skin equivalent models are used for a wide variety of pharmacotoxicological trials. The present study was performed to assess morphologically the effect of podophyllotoxin on human bioengineered skin. The untreated model exhibited many resemblances with the parent tissues, although the epidermal differentiation was slightly impaired at the ultrastructural level. The penetration of podophyllotoxin and its biological effects inside the model appeared largely increased compared to the clinical experience with the drug. Acantholysis and cytolytic changes were prominent mimicking the effect of cantharidin. The exaggerated response of many skin equivalents to various compounds shed some doubts on the validity of the model when it is used to show efficacy rather than toxicity. This might apply to claims of efficacy for cosmetic compounds. The effect of cosmetic additives cannot be validated by such approach alone.

Introduction: Cutaneous manifestations of myelodysplastic syndromes are rare and polymorphous. They can be the direct expression of the hematological disease or represent signs of a vasculitis or a neutrophilic syndrome. Myelodysplastic syndromes progress sometimes toward an acute leukemia., Observation: A 53-year-old woman suffering from myelodysplastic syndrome presented for several months a cutaneous vasculitis without any histological specificity. In time, such presentation was complicated by the simultaneous occurrence of a cutaneous Langerhans cell histiocytosis and an acute monoblastic leukemia type LMA 4. The disease was rapidly fatal., Discussion: The complication of a myelodysplastic syndrome by concurrent Langerhans cell histiocytosis and acute monoblastic leukemia suggests a pathogenic relationship between these two latter disorders.

Background: Surfactants elicit alterations in the stratum corneum. Predictive tests that avoid animal experimentation are needed., Objective: This study compares three methods of rating and predicting shampoo-induced irritation., Methods: Corneosurfametry entails collection of stratum corneum followed by brief contact with diluted surfactants and measurement of variations in staining of samples., Results: Corneosurfametry appears to correlate well with in vivo testing in volunteers with sensitive skin. However, corneosurfametry presents less interindividual variability than in vivo testing and allows better discrimination among mild products. Morphologic information about surfactant-induced loosening of corneocytes may be increased by testing surfactants on human skin equivalent. Results are similar to those provided by specimens used for corneosurfametry., Conclusion: The corneosurfametric prediction of surfactant irritancy correlates with in vivo testing and with in vitro evaluation on human skin equivalent.

Background: Congenital histiocytosis is divided into four entities differing in their clinical and histological features and prognosis. Early, accurate diagnosis is essential for treatment., Case Report: Seven cutaneous nodules were seen in a male neonate. One of these nodules was biopsied on the 7th day of life; it showed the typical findings of Hashimoto-Pritzker reticulohistiocytosis by optical and electron microscopy using immunological markers. The nodules spontaneously disappeared after a few months., Conclusions: Congenital forms of histiocytosis must be accurately characterized. Hashimoto-Pritzker reticulohistiocytosis is a benign and self-healing disease restricted to the skin, while the Letterer-Siwe disease has a completely different course and treatment.

This report is the first to study histological, immunopathological, ultrastructural, and morphometric aspects of the abnormal structure of the dermis in Ehlers-Danlos syndrome, type VIIc. This disease, resulting from a defect in procollagen peptidase, resembles dermatosparaxis in animals. Dermal cells were abnormal in many aspects, including their large number, their strong argent affinity, and the occasional presence of oligocilia. Factor XIIIa-positive dendrocytes were, however, few in number. The stroma had many tears resulting from the absence of collagen bundles replaced by a loose meshwork of cauliflower fibrils. The mean collagen area, measured from fibrils, was similar to normal, and the individual values of this parameter were inversely related to the form factor that quantifies irregularity in fibril shape. Basement membranes were also defective, with an apparent paucity or focal absence of type IV collagen and laminin. The biology responsible for these many alterations in dermal structure is complex and not yet understood. The many morphological changes seen in Ehlers-Danlos syndrome, type VIIc, underscore the complexity of cell-matrix interactions in establishing a normal dermis.

We report an ultrastructural study of azidothymidine-induced melanoderma. The hyperpigmentation is linked to the presence of numerous single melanosomes and polymelanosomes in keratinocytes at all levels of the epidermis, and in dermal Factor XIIIa-positive dendrocytes. Such observation suggests an increased melanogenesis in melanocytes associated to a defect in the degradation of melanosomes normally occurring during epidermal maturation.

We present an immunopathological and electronmicroscopic study of the skin of two newborns affected by restrictive dermopathy. Evidence of abnormal maturation was found in the epidermis, cutaneous appendages, dermis, and hypodermis. Our observations confirm two previous descriptions. We emphasize some unreported data concerning the L1 antigen and Factor XIIIa in the skin. The L1 antigen is expressed in the interadnexal epidermis, but not in hair follicles. This is the reverse pattern compared with normal skin. Factor XIIIa is poorly expressed in dermal dendrocytes, which appear rare compared with controls. The multiple defects in maturation found in all cutaneous tissues suggest a qualitative or quantitative aberration in control mechanisms of tissue interactions.

Restrictive dermopathy is a rare, lethal autosomal recessive syndrome. We report on 3 unrelated affected stillborn infants of consanguineous parents. Clinical findings include a tight, thin, translucent, taut skin, which tears spontaneously in flexion creases, arthrogryposis multiplex congenita (including the temporomandibular joint), enlarged fontanelles, typical face and dysplasia of clavicles and long bones. Histologic abnormalities include hyperplastic, abnormally keratinized epidermis, reduced tonofilaments, thin, compact dermis with hypoplasia of the elastic fibres, and abnormal subcutaneous fat. Fifteen previous cases are reviewed.

Chemical warfare agents have been used in recent conflicts. We present a review of the clinical manifestations of mustard gas casualties and we studied the histological presentation of cutaneous lesions. Four groups of alterations were recognized, namely (a) alterations of keratinocytes, (b) epidermal hyperplasia with or without atypia, (c) alterations of the melanocytic system, and (d) structural changes of the dermis.