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Lichen planus (LP) is an auto-inflammatory skin disorder identified by a presence of T-cell lymphocytes at the dermal-epidermal junction. It is hypothesized that the INF-γ/CXCL10 axis fulfills a major role in the onset and persistence of chronic inflammation in LP. Since Janus kinases (JAKs) are involved in the transduction of INF-γ signals, they may be good targets for LP treatment. Several case reports and case series described the safety and efficacy of upadacitinib (2 articles), tofacitinib (6 articles), baricitinib (4 articles), and Ruxolitinib (1 Article) in the treatment of LP variants. The predominant variants that JAK inhibitors improved were lichen planopilaris, nail LP, and erosive LP. Considering the role of the JAK pathway in LP pathogenesis and the evidence provided by these reports, it seems JAK inhibitors would be effective therapeutic agents for LP treatment. Hence, these agents should be trialed and evaluated further.

Background: Ashy dermatosis (AD) and lichen planus pigmentosus (LPP) are both acquired macular pigmentation of uncertain aetiology. Despite the controversy surrounding their entities, recent global consensus has concluded that they are 2 different diseases with distinct clinical presentations. Nevertheless, there are limited data on their histopathological comparisons., Objective: To evaluate the differences in histopathological findings between AD and LPP., Methods: Electronic records and photographs of patients with the diagnosis of AD or LPP from January 2008 to December 2018 were retrospectively reviewed by a dermatologist. Patients were then classified into groups with AD and LPP, based on the clinical descriptions from the recent consensus. Those with history/clinical presentations suggestive of other causes of macular pigmentation were excluded. The histopathological diagnosis of AD and LPP was then reevaluated by a blinded dermatopathologist., Results: One hundred and twenty-four patients with acquired macular pigmentation were identified; 24 were excluded due to clinical history or photographs being inconsistent with AD or LPP. Of the remaining 100 patients, 71 had clinical findings consistent with LPP while 29 had AD. The prevalence of epidermal hyperkeratosis was significantly higher in LPP when compared to AD (33.8% vs. 0%, p < 0.001), as well as epidermal hypergranulosis (35.2% vs. 0%, p < 0.001), lichenoid dermatitis (49.3% vs. 7.1%, p < 0.001), perifollicular infiltration (47.9% vs.10.3%, p < 0.001), and perifollicular fibrosis (35.2% vs. 10.3%, p =0.01). In addition, the degree of pigmentary incontinence was more severe in LPP (21.1% vs. 3.5%, p =0.015). For AD, vacuolization of the epidermal basal cell layer was more common (96.4% vs. 77.5%, p =0.02)., Conclusions: Although most cases of AD and LPP can be diagnosed clinically, in doubtful cases, histopathological findings of lichenoid dermatitis, epidermal hyperkeratosis/hypergranulosis, and moderate to severe pigmentary incontinence can help distinguish LPP from AD., Competing Interests: The authors declare that there are no conflicts of interest regarding the publication of this paper., (Copyright © 2019 Suthinee Rutnin et al.)

Competing Interests: Competing interests: None declared.

Background: Lichen planus (LP) is an inflammatory skin disease with unknown aetiology. Activation by pathogen-associated molecular patterns or environmental stimuli may activate some components of inflammasomes that contribute to the inflammatory process in LP lesions., Aim: To characterize the inflammasomes in skin lesions and peripheral blood mononuclear cells (PBMCs) of patients with LP under Toll-like receptor (TLR) activation., Methods: In total, 15 patients with LP and 14 healthy controls (HCs) were enrolled in the study. Inflammasome expression in skin was evaluated by real-time PCR and immunohistochemistry, while ELISA was used to assess the production of interleukin (IL)-1β by PBMCs under stimulation with TLR4 and TLR7/TLR8 agonists and adenosine triphosphate (ATP)., Results: Compared with the levels in HC samples, increased expression of the inflammasome AIM2 was verified in both epidermal and dermal sections of LP skin lesions, whereas NLRP1 and IL-β expression levels were enhanced in the dermis. LP skin lesion samples exhibited higher AIM2 transcript levels, similar NLRP1 levels and lower pro-IL-1β mRNA levels compared with HC samples. We verified that, compared with PBMCs from HC subjects, PBMCs from patients with LP produced similar amounts of IL-1β after induction by TLR4 agonists but lower IL-1β levels after induction by TLR7/TLR8 agonists, regardless of the addition of ATP., Conclusion: Alterations in innate immunity, such as inflammasome component expression in skin lesions and PBMCs, were observed in patients with LP. Further investigations of dysfunctional inflammasome activation and the chronic inflammatory status of LP are required., (© 2018 British Association of Dermatologists.)

Deriving from the Greek word λειχήν for "tree moss" and the Latin word planus for "planar," lichen planus is a relatively uncommon and heterogeneous cutaneous disorder that typically develops in middle-aged adults. Despite the significant clinical burden associated with the disorder, little well-conducted molecular research has been undertaken, possibly because of heterogeneity impeding consistent and confident phenotyping. The multiple variants of lichenoid disease bear overlapping clinical and pathologic features despite manifesting as distinct clinical disorders. The first article in this 2-part continuing medical education series provides a comprehensive overview of the clinical and pathologic characteristics of cutaneous lichenoid dermatoses and links these manifestations to recent advances in our understanding of the underlying pathobiology of such diseases., (Copyright © 2018 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.)

Dermatoscopy and in vivo reflectance confocal microscopy are noninvasive techniques that provide a horizontal approach, with an en face view of the skin structures. Both techniques assist in the clinical diagnosis of a variety of inflammatory and infectious cutaneous disorders. In many cases, they have shown concordance. Their combined use represents, in several instances, a promising option to reach the final diagnosis without the need for invasive procedures., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Introduction: Lichen planus is an inflammatory mucocutaneous disorder, often idiopathic. It is postulated that the characteristic skin lesions arise from a T cell mediated autoimmune response against basal keratinocytes. Oral mucosal involvement can occur in up to 70 % of cases of cutaneous disease however, oesphageal involvement is rare., Result: We report the case of a 60 year old female with ulcerative oesphagitis and concomitant cutaneous lesions suggestive of lichen planus. Multiple immunosuppressant therapies were administered but with little success, except for pulses of oral steroids., Conclusion: Oesphageal lichen planus is rare, often unrecognised and can be resistant to treatment. However, diagnosis is crucial as malignant transformation of longstanding ulcerative lichen planus may occur.

Background: Blaschko-Linear Manifestations of Multifactorial Polygenic Diseases (BLMMPD) are rare. Their underlying pathogenesis is not known but genetic mosaicism is supposed to be involved., Objectives: To describe a series of patients with BLMMPD and to establish a meaningful classification of these manifestations., Materials & Methods: We retrospectively retrieved the records of all the patients with Blaschko-linear lesions followed at our institution between 1994 and 2007. Only well-documented cases of BLMMPD were included., Results: 17 cases were reviewed (11 men and 6 women, mean age 42 years), and the following diagnoses were established: psoriasis (4 cases), lupus erythematosus (1 case), lichen planus (4 cases), dermatomyositis (1 case), adult-onset lichen striatus (4 cases) and adult-onset blaschkitis (3 cases). Careful analysis allowed us to individualize 4 distinct nosological situations: in "type A" manifestations, patients had isolated Blaschko-linear lesions, either of a disease nosologically characterized in a non-segmental manner ("type Aα", e.g. Blaschko-linear psoriasis) or of a disease defined by its Blaschko-linearity ("type Aβ, e.g. lichen striatus); while in "type B" manifestations, patients had other signs of disease, i.e. either non-segmental skin lesions of the same type ("type Bα", e.g. Blaschko-linear psoriasis plus non Blaschko-linear psoriatic lesions), or distinct cutaneous or extra-cutaneous manifestations ("type Bβ", e.g. Blaschko-linear calcinosis cutis in a patient with otherwise typical dermatomyositis)., Conclusions: We propose a comprehensive classification of BLMMPD in well distinct nosological situations, which should be of help if we wish to elucidate the pathogeny of those complex disorders.

Wounds are a hallmark of various skin diseases. Most patients with wounds suffer from chronic venous insufficiency or other vascular diseases. Autoimmune, infective, metabolic, malignant, some psychiatric and diseases caused by environmental factors like radiation, present with skin and mucosal erosions and ulcerations. Lichen planus, lichen sclerosus, toxic epidermal necrolysis, Kaposi sarcoma, genodermatoses like Hailey-Hailey and Darier's disease belong to different dermatological entities, they have different etiology, pathogenesis and clinical presentation, but at some stage ulcerations and erosions dominate through the disease course as a result of complications of untreated disease or as part of a complex clinical presentation. Wounds demand a different multidisciplinary therapeutic approach, sometimes even in intensive care unit, where special care is available. Most patients are followed-up to avoid fatal complications like sepsis, as well as a potential malignant transformation of cells in the environment of chronic inflammation. Wounds are found in female genital lichen planus and lichen sclerosus. Oral lichen planus has a potential for malignant transformation and is considered a precancerous disease. Toxic epidermal necrolysis is a life threatening disease similar to burns. Wounds cover most of the body surface as well as mucosa. The high mortality rate is due to complications like sepsis, loss of thermoregulation, electrolyte and fluid disbalance and shock. Chronic wounds are also a hallmark of skin tumors and other skin malignancies like Kaposi sarcoma and lymphoma. The primary treatment goal in genodermatoses like epidermolysis bullosa is wound care, and to a less extent in other inherited skin diseases like Hailey-Hailey and Darier's disease wound healing is important for sustaining a good quality of life in affected individuals.

In vivo reflectance confocal microscopy (RCM) is a non-invasive diagnostic technique that offers the evaluation of the skin at real time with cellular resolution. In the past decade, multiple studies have been performed showing the clinical applicability of RCM for the diagnosis of melanoma and non melanoma skin cancer (NMSC). In this regard, RCM has moved from a research tool to a valuable diagnostic technique being applied in daily clinical practice. In this regard, RCM aids in the diagnosis and differential diagnosis of various skin diseases and may also be used for selection of the biopsy site. Furthermore, RCM allows monitoring of a skin lesion over time without tissue alteration and thus represents a valuable method for treatment monitoring.

Linear skin diseases may follow Blaschko's lines, Langer's relaxed skin tension lines or head zones (dermatomes), thus indicating an embryogenic, hematogenic or neuronal aspect in their pathogenesis. Köbner phenomenon describes the eruption of an inflammatory skin disease following mechanical alteration of the skin. Renbök phenomenon describes an area of non-involvement in an otherwise generalized skin disease. Wolf's isotopic response may be understood as a special subtype of Köbner phenomenon, in which one skin disease triggers a second one. Pathogenically unrelated skin diseases may follow a zosteriform distribution, if they are linked to a preceding herpes zoster by Köbner phenomenon, Renbök phenomenon or an isotopic response. We report three instructive patients diagnosed with Wegener's granulomatosis, cutaneous graft-versus-host disease and lichen planus, whose skin manifestations were following or sparing a zosteriform distribution pattern. Köbner phenomenon, Renbök phenomenon or Wolf's isotopic response may link pathogenically unrelated skin diseases to a zosteriform pattern, which may present diagnostic difficulties even for dermatologists., (© 2011 Japanese Dermatological Association.)

Diagnoses in dermatopathology are capable of improvement. Clinical pictures should be evaluated along with skin biopsy specimens whenever possible., (© The Authors • Journal compilation © Blackwell Verlag GmbH, Berlin.)

Immunofluorescence is a valuable auxiliary diagnostic tool for autoimmune bullous diseases and inflammatory disorders, since their clinical and histopathologic findings may be inconclusive. It is a feasible laboratory method that requires experienced technicians and detects in situ and circulating immune deposits that may be involved in the pathogenesis of such skin diseases.

Sixty-one percent of refractory vulvodynia patients evaluated in a tertiary care vulvovaginal clinic had clinically relevant dermatoses based on dermatopathologist-analyzed vulvar biopsy including: lichen sclerosus, allergic/irritant dermatitis, lichen planus, and other inflammatory or neoplastic dermatoses. Given the frequency of dermatologic disease, vulvar biopsy and analysis by a dermatopathologist are recommended in patients with vulvodynia.

Background: Lichenoid graft-versus-host disease (liGVHD) histologically shares several common features with other lichenoid dermatoses, such as cutaneous lupus erythematosus and lichen planus (LP), which collectively show a junctional infiltrate of cytotoxic lymphocytes with liquefaction of the basal layer ("interface dermatitis"). Because recent studies have shown a role for type I interferon (IFN)-associated inflammation, including lymphocyte recruitment via CXCR3 <-> ligand interaction in cutaneous lupus erythematosus and LP, we hypothesized that similar mechanisms might also be involved in liGVHD., Methods: Ten representative lesional skin biopsies taken from patients with different subsets of chronic cutaneous graft versus host disease (GvDH) were recovered from the authors' archives. Eight LP specimens and 5 punch biopsies taken from healthy skin were analyzed for control purposes. Immunohistochemistry was performed to characterize the lesional infiltrate (CD3, CD4, CD8, CD20, CD56, or CD68), to analyze type I IFN signaling (MxA), and to investigate expression of the IFN-inducible chemokines CXCL9 and CXCL10 and their ligand CXCR3. In situ hybridization was performed to visualize IFNalpha expression on the mRNA level., Results: Our analyses revealed striking similarities between the inflammatory pattern seen in LP and liGVHD. Both disorders presented with a predominantly T-cellular inflammation with CD8(+) lymphocytes affecting the basal epidermal layer. The majority of lesional lymphocytes expressed the chemokine receptor CXCR3. The corresponding chemokines CXCL9 and CXCL10 were found in the epidermis and within the inflammatory infiltrate. Analyses of MxA and IFNalpha mRNA expression supported a role for type I IFNs in these conditions., Limitations: This study was limited by the number of well characterized cases in our archives. In situ hybridization was realizable only in single cases., Conclusion: Our results support the hypothesis that CXCR3 <-> ligand-mediated lymphocyte recruitment is involved in cutaneous liGVHD. The fact that CXCL10 was seen in precisely those areas with extensive liquefaction of the basal epidermis supports a role of this chemokine for the development of the typical histologic "interface" pattern.

Hepatitis C (HCV) is the most common cause of chronic liver disease and hepatocellular carcinoma, as well as the leading indication for liver transplantation in the Western world. For many patients, cutaneous manifestations may be the only, the earliest, or the most apparent sign of the underlying infection. The dermatologic manifestations of HCV infection are reviewed.

Endomucin is an endothelial sialomucin that was recently identified with the help of monoclonal antibodies raised against mouse endothelial cells. Cloning of human endomucin allowed us to generate monoclonal antibodies against soluble recombinant forms of human endomucin. In this study, we investigated the expression of this novel molecule in human skin under different conditions, using the monoclonal antibodies. In normal human skin, endomucin was detected for the monoclonal antibody L6H10 by immunoblotting, and immunohistologic analysis of wax-embedded sections revealed that this glycoprotein is expressed on capillaries, venules, and lymphatic vessels. Interestingly, staining of arterial endothelium was either weak or focal using the monoclonal antibodies against endomucin. In situ hybridization of normal human skin confirmed the expression pattern on the messenger RNA level obtained above. We further analyzed the expression of endomucin in skin biopsy specimens from patients with inflammatory skin diseases, such as atopic dermatitis, psoriasis, lichen planus, cutaneous lupus erythematosus, and T cell lymphoma as well as with vascular skin tumors, such as hemangioma, pyogenic granuloma, angiolipoma, Kaposi's sarcoma, and angiosarcoma. We found endomucin expressed on the endothelium of each tissue, concluding that this novel molecule is a new endothelial-specific marker in the study of normal and diseased human skin.

The T-cell receptor (TCR) zeta-chain is involved in signal transduction necessary for T-cell activation and subsequent proliferation. Expression of the TCR zeta-chain in vivo has been studied by a variety of technical approaches on different cell and tissue specimen. However, the in situ situation concerning the expression of the TCR zeta-chain has not yet been investigated on infiltrating T lymphocytes in neoplastic and inflammatory cutaneous diseases. In this study, we analysed the expression of the TCR zeta-chain in a number of skin tissues affected by established inflammatory and neoplastic conditions. Serial sections of different tissue specimens were stained immunoenzymatically for CD3 and TCR zeta-chain expression. No or at most scarce expression of TCR zeta-chain was detectable in the inflammatory and neoplastic skin conditions investigated as compared to CD3-positive cells. It is possible that this TCR zeta-chain deletion is induced by the skin microenvironment as an effect of local immunoregulatory influences. Alternatively, lymphocytes located in the skin may generally not express this molecule. In our study, tumour-infiltrating T lymphocytes of CTCL were negative for TCR zeta-chain expression. It has been hypothesized that downregulation of the TCR zeta-chain on tumour-infiltrating T lymphocytes is a mechanism by which neoplastic cells escape the cellular immune response. Our findings showing the absence or reduction of TCR zeta-chain expression also in inflammatory skin lymphocytic infiltrates is not consistent with a pivotal role of the TCR zeta-chain in the process of immune escape of tumour cells.

Antigen-presenting cells (APCs) participate in the initiation of the inflammatory process in various immune-mediated dermatoses through the activation of antigen-specific T lymphocytes. The skin contains several different subsets of APCs. To investigate the role of these APCs in T-cell immune-mediated inflammation, we examined the distribution and numbers of epidermal and dermal CD1a(+) dendritic cells (DCs), factor XIIIa(+) dermal DCs, and CD68(+) macrophages in five T-cell-mediated inflammatory skin diseases. Immunohistochemistry of CD1a, factor XIIIa, and CD68 was performed using paraffin-embedded tissue obtained from a total of 51 patients with eczematous dermatitis (histologically spongiotic dermatitis), psoriasis, lichen planus, acute graft-versus-host disease (GVHD), and chronic GVHD. The numbers of positive cells for each staining were compared with those in site-matched normal skin control specimens from aged-matched subjects. In spongiotic dermatitis and lichen planus, the numbers of epidermal and dermal CD1a(+) cells and factor XIIIa(+) cells were significantly greater than in normal control skin, while in psoriasis only factor XIIIa(+) cells were significantly increased in number. Acute and chronic GVHD showed a reduced number of dermal CD1a(+) cells. Interestingly, factor XIIIa(+) cells were decreased in acute GVHD while they were increased in chronic GVHD. There was a significant reduction in epidermal CD1a(+) cells in acute GVHD, but not in chronic GVHD. The differences in the numbers of APCs in lesional skin appeared to reflect differences in the pathophysiology of these inflammatory skin diseases.

To elucidate the pathogenesis of T cell-mediated inflammatory skin diseases, we examined the exact sites where CD8(+) T cells proliferate, correlating them with the localization of antigen-presenting dendritic cells. We performed CD8/Ki-67 double immunohistochemical staining and single staining for CD1a, CD68, and factor XIIIa on sections of paraffin-embedded tissue samples of inflammatory dermatoses in which T lymphocytes are thought to play a crucial role. The dermatoses were lichen planus (12 samples), acute graft-versus host disease (GVHD) (12 samples), chronic GVHD (10 samples), spongiotic dermatitis (8 samples) and psoriasis (7 samples). Labelling for Ki-67 among CD8(+) T cells was predominantly observed in the subepidermal lymphoid infiltrate, and was scanty in the epidermis. This suggested that proliferation of CD8(+) T cells occurred preferentially in the dermis. The labelling index for Ki-67 among dermal and epidermal CD8(+) cells was quite different among the different diseases studied (P < 0.05). They were rich in the subepidermal portion of the dermis of spongiotic dermatitis, acute GVHD and chronic GVHD, but rare in the dermis of psoriasis and lichen planus. A moderate infiltrate was also observed in lesional epidermis of spongiotic dermatitis, acute GVHD and chronic GVHD, whereas they was almost none in the epidermis of psoriasis and lichen planus. CD1a(+) dermal dendritic cells were densely distributed within the lymphoid infiltrate in the affected dermis of spongiotic dermatitis, psoriasis and lichen planus, whereas they were minimal in GVHD. These dermal dendritic cells are candidates as stimulators on T cells in the dermis. In conclusion, the proliferative status of T cells could be an important clue in the elucidation of the pathophysiology of T cell-mediated inflammatory dermatoses.

Dermatoses of the male genitalia can be confusing to identify and difficult to diagnose and treat. Rashes and lesions that occur on other areas of the body can be hard to recognize when they appear on the genitalia. In this article, Dr Goldman reviews the common dermatoses, presents defining characteristics, and suggests treatment options.

The results of several investigations proved that, in special circumstances, human keratinocytes (HKs) synthesize and express cell surface moieties characteristic of effector and/or accessory cells of the immune system, such as CD16, CD36, HLA-DR, and intercellular adhesion molecule-1 (CD54), which are all detectable on the surfaces of macrophages. In the present study, skin biopsies from healthy volunteers, from positive tuberculin skin tests, and from patients with acute urticaria (AU), lichen planus (LP), psoriasis vulgaris (PV), mycosis fungoides (MF), and purpura pigmentosa chronica (PPC) were investigated by means of a multistep immunoperoxidase method to examine the reactivity of the HKs with a panel of monoclonal antibodies (MABs) characteristic of monocyte/macrophage cell lines. In biopsies obtained from positive tuberculin tests and from clinically involved skin of patients with LP, PV, MF, or PPC, a multifocal, positive peroxidase reaction was observed on the membranes of HKs of the basal and suprabasal cell layers when the MABs OKM13 (CD13), OKM14 (CD14), and Dako-Macrophage (CD68) were used. In contrast, specific staining of the HKs was not observed with the same antibodies in the biopsies of healthy volunteers or of patients with AU or in the uninvolved skin specimens obtained from the other patients. The HKs of PV, LP, MF, PPC, and AU patients and those of the healthy subjects all failed to give positive reactions when MABs against CD11b, CD15, or CD33 were used. The published data supplement the known surface characteristics of HKs, reflecting their stage of activation and differentiation.

We report 3 cases of very rare dermatoses with retroauricular location, having lesions of "milia en plaque" type. These dermatoses are the retroauricular follicular lichen planus tumidus, the retroauricular "milia en plaque" and an exceptional case of sebocystomatosis (steatocystoma multiplex) with exclusively retroauricular location, which is unique in the literature. In this group of retroauricular dermatoses can also be included the small retention cysts and comedones of the retroauricular area, attributed to paraffin products in shaving soap inadequately rinsed from this region. On the occasion of these cases we make a review of the literature and a detailed study of the retroauricular follicular lichen planus tumidus and retroauricular milia en plaque and we discuss the differential diagnosis emphasizing the clinical and histologic features, which permit to make the accurate diagnosis.

A rare type of cutaneous papular sarcoidosis is the lichenoid form. We describe a 36-year-old woman who presented with a symmetrical, asymptomatic lichen-like eruption on her upper limbs. The biopsy showed a non-necrotizing granulomatous infiltrate compatible with sarcoid. Chest X-ray revealed Type I bilateral, asymptomatic, hilar adenopathy with no parenchymal abnormalities. High levels of angiotensin converting enzyme and a 67gallium lung scan supported the diagnosis of sarcoidosis.

An illustrative case report and a series of 18 well-documented cases of lichen striatus are presented. The mean age at diagnosis was 3 years (6 months to 14 years; median 2 years). The lesions were predominantly distributed on the trunk in 33% of cases and on the limbs in the remaining two thirds (upper limb: 48%; lower limb: 19%). Pruritus was noted in only 1 of 18 cases. Six cases were associated with clinical features of atopy and/or minor signs of atopic dermatitis (e.g., pityriasis alba). Two cases were considered to be clinically associated with lesions consistent with psoriasis. The mean duration was 9.5 months (4 weeks to 3 years; median 6 months). In one patient, two relapses occurred in 4 years. Hypochromic sequelae were noted in 50% of cases. Lichen striatus is the most common acquired self-limited linear eruption in childhood that follows Blaschko's lines. A new acronym is proposed to emphasize the developmental background of the disease: BLAISE for Blaschko linear acquired inflammatory skin eruption.

Lichenoid dermatosis is a pattern description of a variety of cutaneous lesions which primarily affect the dermoepidermal junction. Involvement of skin appendages has been restricted to hair follicles in lichen planopilaris and discoid lupus erythematosus. Sweat gland involvement has not been described in the four common members of this group, namely, lichen planus, discoid lupus erythematosus, fixed drug eruptions and erythema multiforme, although structural abnormalities have been reported in graft-versus-host disease. In a detailed morphological study of 59 cases, including lichen planus (12), discoid lupus erythematosus (18), fixed drug eruption (14) and erythema multiforme (15), 78% (47/59) showed sweat, gland abnormalities. The abnormalities included vacuolation of cell cytoplasm, with and without lymphocytic infiltration, apoptosis of basal cells and basal cell hyperplasia of the excretory ducts which predominantly affected the portion of the duct adjoining the acrosyringium. The portion of the duct close to the secretory gland was only involved in continuity and the secretory glands were unaffected. These abnormalities of the sweat gland mostly constitute primary involvement by the disease process in contrast to structural abnormalities secondary to fibrosis.

The pathogenesis of macular amyloidosis and lichen amyloidosis remains unsolved and the primary amyloid fibril protein(s) has not yet been identified. Ultrastructural association of skin amyloid with elastin associated microfibrils has been noted earlier. The presence of fibrillin in conjunction with such microfibrils was recently demonstrated immunohistochemically. The presence of fibrillin immunoreactivity in the amyloid deposits in skin biopsies from 3 patients with macular amyloidosis and 3 patients with lichen amyloidosis was studied, using monoclonal anti-fibrillin antibodies. For comparison, skin specimens were studied from five patients with lichen ruber planus, four patients with erythropoietic protoporphyria and from a patient with myeloma-associated cutaneous amyloidosis. Renal specimens from two cases of the amyloid A type of renal amyloidosis also were investigated. There was no immunostaining either of the keratin bodies in specimens of lichen ruber planus, the cutaneous PAS-positive vascular deposits in patients with erythropoietic protoporphyria, or the amyloid deposits in specimens of systemic amyloidosis and it was faint or absent in amyloid deposits in the specimens from patients with lichen amyloidosis. In contrast, distinct fibrillin immunoreactivity could be demonstrated in amyloid deposits in specimens from patients with macular amyloidosis. It was sometimes absent in deposits located in the upper part of the papillary dermis, close to the dermal epidermal junction zone, while consistently strong in deposits located lower down in the dermis. The results suggest that fibrillin or part of the fibrillin molecule may be present in some of the amyloid deposits in specimens of macular amyloidosis.

Many dermatoses may exhibit lesions distributed in a linear fashion: the linearity may be related to anatomical structures (blood or lymph vessels, nerves), to mechanical factors (urticarial dermographism, striae distensae cutis, frictional melanosis) or to some other provocative injuries being themselves linear (for instance Köbner's phenomenon). Some congenital or acquired dermatoses, either inherited or sporadic, have a linear distribution following the embryonic lines described in 1901 by A. Blaschko. Most of them are nevoid skin lesions present at birth or having a later onset: epidermal nevi (naevus unius lateris, linear porokeratosis), adnexal nevi (linear sebaceous nevus, linear basal cell nevus), pigmented lesions (systematized linear achromic nevus) or intricated nevi of the connective tissue (angio-lipomatous nevus). More seldom, genodermatoses related to a X-chromosomal mosaicism, occurring in females only, exhibit also a linear arrangement of their skin symptoms following Blaschko's lines: incontinentia pigmenti, focal dermal hypoplasia, etc. There are also very common inflammatory skin diseases, without any genetical background, which sometimes present as linear dermatoses. Their pattern according to Blaschko's lines is obvious in some cases: linear lichen planus, linear lichen nitidus, linear scleroderma, linear (zosteriform) vitiligo, linear fixed drug eruption, linear chronic lupus erythematosus. In some other conditions, the arrangement following these lines is probable (lichen striatus, linear eczema) or dubious (unilateral nevoid telangiectasias). This case report concerns a 38-year old man exhibiting relapsing inflammatory linear lesions of Blaschko's lines on the chest, back and upper limbs. Histological examination showed a non specific spongiotic dermatitis with rare necrotic keratinocytes and exocytosis of lymphocytes in the stratum spinosum.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunoperoxidase techniques provide the pathologist with the capability for staining a wide range of antigens in tissue sections. More than 100 different antigens have been successfully demonstrated in fixed paraffin sections; other antigens can only be visualized in frozen sections. This latter group particularly includes lymphocyte surface antigens detectable by monoclonal antibodies. This review describes the current state of the art and provides several illustrations of the use of monoclonal antibodies for the identification of T-lymphocyte phenotypes in frozen section from cases of leprosy, mycosis fungoides, halo nevus, Kaposi's sarcoma, lichen planus and atopic dermatitis. Technical details and potential applications are discussed. The growing availability of commercial immunostaining kits makes these techniques more accessible to the surgical pathologist; indeed a whole new range of truly specific, special stains are available, as pathologists we must simply learn to use them.

Blaschko's lines are the pattern assumed by many different naevoid and acquired skin diseases on the human skin and mucosae. They were described and drawn by Blaschko 75 years ago. These lines are to be distinguished from other linear patterns such as Voight's lines, Langer's lines, and the lines of innervation of the spinal nerves. They do not follow any known nervous, vascular or lymphatic structures in the skin. The epidermis and its appendageal structures, the melanocytes, the vascular system, and the fatty hypoderm, all, separately or in combination, may be involved in the morphological manifestations which follow Blaschko's lines. Many of the naevoid skin conditions are lifelong (e.g. linear sebaceous naevus, unilateral naevoid telangiectasia); many of the acquired skin diseases (e.g. lichen striatus, linear psoriasis) are of relatively short duration (e.g. 1-2 years). The cause of the distribution pattern is unknown. It is possibly a form of human 'mosaicism' where certain specific cells or groups of cells react differently from other cells due to chromosomal abnormalities. The embryological explanation of Blaschko's lines is not at all clear. Other markers in addition to the skin findings are needed to determine the time and the nature of the change responsible for these lines. The main purpose of this article is to introduce the concept of Blaschko's lines into the medical, paramedical, and general biological fields of science. In this way, it is hoped that some inter-reaction can occur between those who regularly see Blaschko's lines and those who regularly see and study other chromosomal and embryological abnormalities.

The papulosquamous diseases have certain common morphologic appearances which may at times lead to confusion in diagnosis. They do not have any common etiologic factor. The most common diseases in this category are psoriasis, seborrheic dermatitis, lichen planus, pityriasis rosea, and secondary syphilis. Exfoliative erythroderma is included here since it rarely may be a complication of a pre-existing papulosquamous disease such as psoriasis, seborrheic dermatitis, and lichen planus.

An antiserum prepared against a glycoprotein (GP37) extracted from the upper epidermal layers, was used to stain frozen sections of human oral mucosa, normal and abnormal skin by an indirect immunofluorescence technique. On normal human epidermis, this antiserum mainly reacted with the cytoplasm of granular cells, whereas on buccal mucosa the recognized antigen was observed as scattered dots limited to the upper epithelial layers. In epidermal diseases, alterations in the staining pattern were observed. In psoriasis, the labelling was markedly diminished; in contrast, in lichen planus it was intense and present on the 3-6 uppermost cellular layers. Basal cell epitheliomas were almost negative, except around horn cysts. In Bowen's disease dyskeratotic cells were strongly labelled. In squamous cell carcinomas a clear-cut staining was observed in squamous nests. On cultures, GP37 expression could be induced by growing epidermal cells in vitamin A-depleted medium. The biological significance of the observed staining patterns remains to be precised. Nevertheless, GP37 represents a sensitive marker of epidermal differentiation and may be useful in skin pathology and in in vitro studies.

Dermatological conditions characterized by dermo-epidermal separation, basal lamina discontinuity, multiplication, and thickness variability, and/or irregularity of the subepidermal space are discribed. Pathological changes of the dermo-epidermal junction are considered to be destructive or reproductive. Both may appear in combination. Destructive processes may be relfected by dermo-epidermal separation. Epidermal cells and/or dermal connective tissue appear degenerated. Thickening of the lamina may occur by reactive hyperproduction or by precipitation of pathological materials. Reproductive processes of the junction originate in the epidermal cells and are reflected in multilayering of the basal lamina. Interruption of the lamina and irregularity of the subepidermal space often precede these phenomena.

Skin biopsies from leukaemic patients undergoing allogeneic bone marrow transplantations and treated prophylactically with cyclosporin A were analysed using histological, morphometric, and immunohistological techniques. Samples from donors were used to establish normal values. Biopsies taken from recipients two days before grafting were all histologically normal, but on immunohistological staining half of them showed a reduction in the number of epidermal Langerhans' cells and 29% a reduction in T inducer lymphocytes. Thirty two biopsies were taken from patients with rashes at various times after transplantation: 14 showed lichenoid changes consistent with graft versus host disease, three eczematous tissue reactions, two vesicular lesions, and 12 no histological abnormality. One sample showed changes intermediate between the lichenoid and eczematous forms. The numbers of epidermal Langerhans' cells were low during the first few weeks after transplantation and were normal or raised later regardless of histological appearances. Unlike epidermal Langerhans' cells, significant reductions in the numbers of lymphocytes were not seen. Lesions of all histological types contained mixtures of T inducer and T suppressor/cytotoxic cells, although the eczematous and vesicular lesions contained higher proportions of T inducer cells. Epidermal infiltrates invariably contained T suppressor/cytotoxic cells but infiltration of epidermis by T inducer cells occurred only in the presence of normal numbers of epidermal Langerhans' cells. Natural killer cells were not identified. The immunological appearances of the various histological subgroups thus change with time after transplantation.

The phenotype of the cutaneous immunocompetent cells in lesions of cutaneous T cell lymphoma (mycosis fungoides, Sézary syndrome), lichen planus, and chronic graft-vs.-host reaction infiltrates, was examined by the use of monoclonal antibodies directed against T cell populations and Langerhans cells (OKT3, OKT4, OKT5, OKT6, OKT8) (BL2, BL6). In Sézary syndrome, the phenotype of the Sézary cell is homogeneous (OKT3+, OKT4+, OKT8-, OKT6-, BL2-) and corresponds to the phenotype expressed by the normal helper T cell population. At the ultrastructural level, the discontinuous distribution of OKT4 and OKT3 antigenic sites on the cell surface is similar to the HTLA antigens. In skin lesions, the Langerhans cells expressed two specificities shared by normal thymocytes (OKT6 and BL6). We propose that the expression of these antigens could be related to the epithelial microenvironment (epithelium-dependent differentiation antigens). The tumoral lymphoid cells infiltrating the skin showed the same phenotype (helper type) as the circulating Sézary cells (OKT3+, OKT4+, OKT8-, OKT6-). Moreover, the OKT3+ cells also expressed HLA-DR antigens and corresponded to activated T lymphocytes. In lichen planus, our results suggest an immunological reaction similar to a delayed hypersensitivity reaction which includes all of the immunocompetent cell subpopulations, with a first stage of formation by Langerhans cells (OKT6+, BL6+, HLA-DR+) and helper cells, and a second stage mediated by suppressor/cytotoxic cells. The results from the study of graft-vs.-host reaction also suggest a cytotoxic effect mediated by suppressor/cytotoxic cells (OKT3+, OKT4-, OKT8+, HLA-DR+).

Two female patients, with similar clinical characteristics, having as only dermatological manifestation large retroauricular plaques, on their surface could be seen many keratinic follicular cysts with an unspecific lichenoid inflammatory reaction. This entity is studied according to the revised bibliography, reaching the conclusion that they are real infundibulo-pilous cysts in plaques, with a very peculiar localisation, which are not red lichen planus. The authors think that this affection should be considered as an autonomous anatomo-clinical entity.