[Acne inversa/hidradenitis suppurativa: An update]

Acne inversa (AI)/hidradenitis suppurativa is a chronic, recurrent, immune-mediated dermatosis characterized by deep inflammatory nodules, abscesses, fistulas, and undermined scars in skin areas bearing apocrine glands. In addition to the cutaneous manifestation, numerous AI patients show metabolic changes, spondyloarthritis, and depression. AI leads to a strong reduction in the quality of life and an impairment of the sexual life of affected individuals and often culminates in social withdrawal, stigmatization, unemployment, and suicidal thoughts. In this overview, we summarized the most important facts about AI and propose a simple algorithm for therapy.

Photodynamische Therapie – neue Wege, kritische Abwägung

In den letzten Jahren gewinnt die photodynamische Therapie (PDT) an Bedeutung in der Behandlung des chronischen Lichtschadens. Im Vordergrund steht die Behandlung der Feldkanzerisierung und damit von bösartigen, oberflächlichen epidermalen Karzinomen (aktinische Keratosen). Als Nebeneffekt wurde immer wieder ein positiver Effekt auf das Gesamterscheinungsbild und damit ein kosmetischer Effekt beschrieben. Untermauert wird dies durch Untersuchungen zur epidermalen Dicke und aktinischen Elastose nach PDT. In Kombination mit fraktionierten ablativen Lasern oder dem Mikroneedling kann eine synergistische Wirkungsverstärkung erzielt werden. Komplexe Behandlungsschemata, die PDT mit IPL, Farbstoff-Laser sowie Mikroneedling oder Mikrodermabrasion kombinieren, werden sowohl in der eigentlichen Verjüngungsbehandlung, jedoch auch zur Therapie der Akne oder auch infektiöser Hauterkrankungen eingesetzt. Die alleinige kosmetische Anwendung der PDT auf nicht sonnengeschädigter Haut steht auch aufgrund der hohen Kosten und besserer Konkurrenzmethoden nicht im Vordergrund.

The sensitivity and specificity of optical coherence tomography for the assisted diagnosis of nonpigmented basal cell carcinoma: an observational study

BACKGROUND

The diagnostic criteria for basal cell carcinoma (BCC) using optical coherence tomography (OCT) have been described previously, but the clinical value of these findings remains unknown.

OBJECTIVES

To investigate the diagnostic value of OCT for BCC in a typical clinical setting. The primary efficacy end point was a diagnosis of BCC for each lesion. Secondary end points were the diagnosis of other possible conditions.

METHODS

This was an observational, prospective, multicentre study in which consecutive patients with nonpigmented pink lesions suspicious for BCC underwent clinical assessment, dermoscopy and OCT, with the diagnosis recorded at each stage. Once all diagnoses had been recorded, the histological results were disclosed. In total 164 patients with 256 lesions were recruited. Histology was missing for 21 lesions, leaving 235 lesions in 155 patients for analysis.

RESULTS

Sixty per cent of lesions (141 of 235) were identified as BCC by histology. A slight increase of sensitivity was noted following OCT, which did not reach statistical significance. The specificity increased significantly from 28·6% by clinical assessment to 54·3% using dermoscopy and to 75·3% with the addition of OCT (P < 0·001). The positive predictive value for the diagnosis of BCC using OCT was 85·2% [95% confidence interval (CI) 78·6-90·4], and the negative predictive value was 92·1% (95% CI 83·6-97·0). The accuracy of diagnosis for all lesions increased from 65·8% with clinical evaluation to 76·2% following additional dermoscopy and to 87·4% with the addition of OCT.

CONCLUSIONS

OCT significantly improved the diagnostic specificity for BCC compared with clinical assessment and dermoscopy alone.

MGMT gene promoter methylation correlates with tolerance of temozolomide treatment in melanoma but not with clinical outcome

Background:

Despite limited clinical efficacy, treatment with dacarbazine or temozolomide (TMZ) remains the standard therapy for metastatic melanoma. In glioblastoma, promoter methylation of the counteracting DNA repair enzyme O⁶-methylguanine-DNA-methyltransferase (MGMT) correlates with survival of patients exposed to TMZ in combination with radiotherapy. For melanoma, data are limited and controversial.

Methods:

Biopsy samples from 122 patients with metastatic melanoma being treated with TMZ in two multicenter studies of the Dermatologic Cooperative Oncology Group were investigated for MGMT promoter methylation. We used the COBRA (combined bisulphite restriction analysis) technique to determine aberrant methylation of CpG islands in small amounts of genomic DNA isolated from paraffin-embedded tissue sections. To detect aberrant methylation, bisulphite-treated DNA was amplified by PCR, enzyme restricted, and visualised by gel electrophoresis.

Results:

Correlation with clinical data from 117 evaluable patients in a best-response evaluation indicated no statistically significant association between MGMT promoter methylation status and response. A methylated MGMT promoter was observed in 34.8% of responders and 23.4% of non-responders (P=0.29). In addition, no survival advantage for patients with a methylated MGMT promoter was detectable (P=0.79). Interestingly, we found a significant correlation between MGMT methylation and tolerance of therapy. Patients with a methylated MGMT promoter had more severe adverse events, requiring more TMZ dose reductions or discontinuations (P=0.007; OR 2.7 (95% CI: 1.32–5.7)). Analysis of MGMT promoter methylation comparing primaries and different metastases over the clinical course revealed no statistical difference (P=0.49).

Conclusions:

In advanced melanoma MGMT promoter, methylation correlates with tolerance of therapy, but not with clinical outcome.

What causes hidradenitis suppurativa?

Hidradenitis suppurativa (HS)--a rather common, very chronic and debilitating inflammatory skin appendage disorder with a notoriously underestimated burden of disease--has long been a playground for the high priests of nomenclature: Ask a bunch of eminent dermatologists and skin pathologists to publicly share their thoughts on what causes HS, and they will soon get entrenched in a heated debate on whether this historical term is a despicable misnomer. Fortunately, the recently founded Hidradenitis Suppurativa Foundation (HSF; http://www.hs-foundation.org), to which EXP DERMATOL serves as home journal, has broken with this unproductive tradition and has encouraged publication of the current CONTROVERSIES feature. This is exclusively devoted to discussing the pathobiology of this chronic neutrophilic folliculitis of unknown origin. Although traces of terminological bickering remain visible, it does the HS experts in our virtual debate room credit that they engage in a constructive and comprehensive dissection of potential pathogenesis pathways that may culminate in the clinical picture we know under the competing terms HS or acne inversa. These experts sketch more often complementary than mutually exclusive pathogenesis scenarios, and the outlines of a conceivable consensus on the many open pathobiology questions begin to emerge in these CONTROVERSIES. Hopefully, this heralds a welcome new tradition: to get to the molecular heart of HS pathogenesis, which can only be achieved by a renaissance of solid basic HS research, as the key to developing more effective HS therapy.

The non-neuronal cholinergic system of human skin

In human skin both resident and transiently residing cells are part of the extra- or non-neuronal cholinergic system, creating a highly complex and interconnected cosmos in which acetylcholine (ACh) and choline are the natural ligands of nicotinic and muscarinic receptors with regulatory function in both physiology and pathophysiology. ACh is produced in keratinocytes, endothelial cells and most notably in immune competent cells invading the skin at sites of inflammation. The cholinergic system is involved in basic functions of the skin through autocrine, paracrine, and endocrine mechanisms, like keratinocyte proliferation, differentiation, adhesion and migration, epidermal barrier formation, pigment-, sweat- and sebum production, blood circulation, angiogenesis, and a variety of immune reactions. The pathophysiological consequences of this complex cholinergic "concert" are only beginning to be understood. The present review aims at providing insight into basic mechanisms of this highly complex system.

Are desmoglein autoantibodies essential for the immunopathogenesis of pemphigus vulgaris, or just ‘witnesses of disease'?

Pemphigus vulgaris (PV) is fascinating to dermatologists, epithelial biologists and immunologists alike, as its pathogenesis has been clarified to a much greater extent than that of most other organ-specific autoimmune diseases, and as it has provided abundant novel insights into desmoglein biology and pathology along the way. Historically, the most influential PV pathogenesis concept is that of Stanley and Amagai. This concept holds that autoantibodies against desmogleins are both essential and sufficient for epidermal blister formation (acantholysis) by impeding the normal functioning of these major adhesion proteins. However, as with most good theories, this landmark concept has left a number of intriguing and important questions open (or at least has not managed to answer these to everyone's satisfaction). Moreover, selected dissenting voices in the literature have increasingly called attention to what may or may not be construed as inconsistencies in this dominant PV pathogenesis paradigm of the recent past. The present debate feature therefore bravely rises to the challenge of re-examining the entire currently available evidence, as rationally and as undogmatically as possible, by provocatively asking a carefully selected congregation of experts (who have never before jointly published on this controversial topic!) to discuss how essential anti-desmoglein autoantibodies really are in the immunopathogenesis of PV. Not surprisingly, some of our expert "witnesses" in this animated debate propose diametrically opposed answers to this question. While doing so, incisive additional questions are raised that relate to the central one posed, and our attention is called to facts that may deserve more careful consideration than they have received so far. Together with the intriguing (often still very speculative) complementary or alternative pathogenesis scenarios proposed in the following pages, this offers welcome "food for thought" as well as very specific suggestions for important future research directions--within and beyond the camp of PV aficionados. The editors trust that this attempt at a rational public debate of the full evidence that is currently at hand will constructively contribute to further dissecting the exciting--and clinically very relevant!--immunopathogenesis of PV in all its complexity.

Lymphatic endothelium-specific hyaluronan receptor LYVE-1 is expressed by stabilin-1+, F4/80+, CD11b+ macrophages in malignant tumours and wound healing tissue in vivo and in bone marrow cultures in vitro: implications for the assessment of lymphangiogenesis

Lymphangiogenesis is a novel prognostic parameter for several cancers that is preferentially quantified by immunohistochemistry of the lymphatic endothelium-specific hyaluronan receptor LYVE-1. Recently, the specificity of LYVE-1 was challenged by serendipitous observations of LYVE-1 expression in rare tissue macrophages. As expression of the hyaluronan receptor-like molecule stabilin-1 is shared by sinusoidal endothelium and macrophages, a thorough analysis of LYVE-1 expression was performed using macrophage-specific markers in vivo and in vitro. In murine tumour models and excisional wound healing, LYVE-1 expression occurred in a subset of CD11b(+), F4/80(+) tissue macrophages that preferentially co-expressed stabilin-1. Upon comparison of single- and double-labelling immunofluorescence, it became apparent that LYVE-1(+) macrophages mimic sprouting and collapsed lymphatic vessels. In vitro, LYVE-1 expression was induced in 25-40% of murine bone marrow-derived macrophages upon exposure to B16F1 melanoma-conditioned medium and IL-4/dexamethasone. By FACS analysis, 11.5% of bone marrow-derived macrophages were LYVE-1(+), stabilin-1(+) double-positive, while 9.9% were LYVE-1(+), stabilin-1(-) and 33.5% were LYVE-1(-), stabilin-1(+). Northern and western analyses confirmed expression of LYVE-1 mRNA and protein in bone marrow-derived macrophages. In the light of the current debate about true endothelial trans-differentiation versus endothelial mimicry of monocytes/macrophages, LYVE-1(+), stabilin-1(+) non-continuous endothelial-like macrophages will require further developmental and functional analyses. In conclusion, the findings imply that LYVE-1 staining must be supplemented by double labelling with macrophage markers in order to differentiate clearly between LYVE-1(+) lymphatics and LYVE-1(+) tumour-infiltrating macrophages. This improved approach will help to clarify the prognostic significance of lymphangiogenesis in malignant tumours.

Das extraneuronale cholinerge System der Haut

Acetylcholine (ACh) is a prototypical neurotransmitter that has recently been recognized to occur extraneuronally in a large variety of cells. ACh and its nicotinic and muscarinic receptors are produced in the epidermis and in the adnexal structures of the skin in a highly complicated pattern. They are also produced in melanocytes, fibroblasts, endothelial cells and immune cells. Through autocrine, paracrine and endocrine mechanisms, the cholinergic system is involved in the basic functions of the skin, such as keratinocyte differentiation, epidermal barrier formation, sweating, sebum production, blood circulation, angiogenesis and a variety of immune reactions. Hence diseases like acne vulgaris, vitiligo, psoriasis, pemphigus vulgaris and atopic dermatitis may be influenced. The exploration of the extraneuronal cholinergic system of the skin has only just begun.

[Benign cellular fibrous histiocytoma with erosion of the phalanx]

Fibrohistiocytic tumors are characterized by the presence of fibroblast like spindle cells and histiocytes. The benign fibrous histiocytoma (dermatofibroma, BFH) as well as the malignant dermatofibrosarcoma protuberans (DFSP) and the malignant fibrous histiocytoma (MFH) belong to this group. A recurrent painful, hard 2 cm tumor on the left hallux of a 54-year-old woman led to an erosion of the underlying phalanx. The patient had suffered from ingrown toenails for more than 10 years. Histologically there was a deep penetrating fibrohistiocytic tumor that grew in a storiform pattern with interspersed foam cells. The tumor was CD34 negative and mitoses were scarce. The diagnosis was benign cellular fibrous histiocytoma (BZFH). BZFH belong to the group of BFH with a high recurrence rate especially after incomplete removal. Damage to the underlying bone has not been reported so far.

Cytokeratins as markers of follicular differentiation: an immunohistochemical study of trichoblastoma and basal cell carcinoma

Trichoblastoma(s) (TB) are benign neoplasms of follicular differentiation frequently found in nevus sebaceus. Many morphologic features are shared with nodular basal cell carcinoma(s) (BCC), sometimes rendering the differential diagnosis difficult. Because both neoplasms can simulate components of mature hair follicles histologically, we attempted to corroborate this by immunohistochemical examination of cytokeratins and hair keratins differentially expressed in the hair follicle. Trichoblastoma(s) and BCC showed homogenous expression of CK14 and CK17. The innermost cells of the tumor nodules in all TB and in 72% of BCC were positive for CK6hf. Using a specific CK15 antibody, 38% of TB showed a focal labeling and all BCC remained negative; 70% of TB and 22% of BCC expressed CK19. CK8 was expressed by numerous Merkel cells present in all TB but in none of the BCC examined. All type I and II hair keratins tested, (especially hHa1, hHa5, and hHa8) remained negative in all tumors examined. Trichoblastoma(s) and BCC show consistent expression of CK6hf, CK14, and CK17; variable expression of CK15 and CK19; and absence of hair keratins. This indicates a differentiation toward the outer root sheath epithelium or the companion layer and not toward the inner root sheath, matrix, or cortex.

Malignant transformation of multiple dermal cylindromas

Cylindromas are benign tumours arising as small, solitary, slow-growing nodules on the head and neck. Multiple cylindromas may form a 'turban tumour' in the autosomal dominant Brooke-Spiegler syndrome. We report two unusual cases of multiple cylindromas with transformation into cylindrocarcinomas. The first patient, a 63-year-old white woman, developed a cylindrocarcinoma on pre-existing multiple cylindromas on her right shoulder. Eight months after resection she developed a lymph node metastasis in the right axilla. The second patient, a 68-year-old white woman, presented with multiple cylindromas of the scalp. One of these transformed into a cylindrocarcinoma, infiltrating the dura mater, with local recurrence 2 years after incomplete resection and postoperative radiation.

Koebner phenomenon due to scratch test in scleromyxoedema

The Koebner phenomenon or isomorphic response was originally described in psoriasis and has subsequently been observed in various other diseases. We report a patient with isomorphic response in scleromyxoedema, a variant of papular mucinosis with diffuse infiltration of the skin. The Koebner phenomenon was due to a scratch test performed 4 weeks before the appearance of streaky, lichenoid infiltrations on the forearms.

Kongenitale multiple disseminierte Glomustumoren

Glomangiome sind benigne Gefäßtumoren, welche vom neuromyoarteriellen Anteil der Glomuskörperchen abstammen. Glomustumoren treten zumeist solitär als schmerzhafte Knoten auf, können aber auch segmental oder am gesamten Integument disseminiert vorkommen. In der Regel manifestieren sich diese Tumoren in der Kindheit. Kongenitale multiple Glomustumoren sind als Rarität einzustufen und wurden bisher nur in Einzelfällen publiziert.

Wir berichten über einen 20-jährigen Patienten mit multiplen, disseminierten, kongenitalen Glomangiomen. Neben den histologischen und immunhistologischen Befunden werden die verschiedenen Therapiemöglichkeiten wie Exzision, Sklerosierung, Kontaktkryotherapie und Lasertherapie dargestellt und die Differenzialdiagnose dieses seltenen Krankheitsbildes diskutiert.

Forms of epithelial differentiation of draining sinus in acne inversa (hidradenitis suppurativa)

The draining sinus is a late complication of several forms of severe acne, leading to extensive, periodically inflamed lesions that are undermined by a system of fistulas, supposed to be of follicular origin. We investigated the expression of various cytokeratins (CKs) and desmosomal proteins in the draining sinus of acne inversa (hidradenitis suppurativa) using monoclonal antibodies in immunohistochemistry on paraffin-embedded sections. We were able to define three different phenotypes of stratified squamous epithelia covering the sinus tracts. Type I epithelium was cornifying and characterized by the presence of CK 10, desmogleins 1-3 and desmocollins 1-3 in an epidermis-like pattern. Type II epithelium was non-cornifying, negative for CK 10 and positive for CK 13. It was negative for desmocollin 1 but strongly immunopositive for desmoglein 1 suprabasally and for desmoglein 2 in the basal cells. Type III epithelium was non-cornifying and strongly inflamed. It was marked by the presence of CK 7, CK 19 and desmoglein 2 and the absence of CK 10, desmoglein 1 and desmocollin 1. In both type II and III epithelium, desmoglein 3, desmocollin 2 and desmocollin 3 showed an inverted staining pattern as compared with normal epidermis and type I epithelium. Desmoglein 2 and CK 5/14 always remained restricted to the basal cell layer. Antibodies against CK 6 and CK 13/15/16 were immunopositive in all three phenotypes and CK 17 was predominantly immunolocalized to suprabasal layers of type II and III epithelium. The three phenotypes are characterized as pathological stratified squamous epithelia reflecting the dynamic process of inflammation, proliferation and stratification taking place in acne inversa.

Compositionally different desmosomes in the various compartments of the human hair follicle

Hair follicles are complex organs of the skin, in morphological and ontogenic continuity with the epidermis. We have examined the location of desmosomal cadherins and desmosomal plaque proteins in the hair follicle of adult and fetal human scalp skin by immunohistochemistry and have established a localization "map" of the hair follicle. Using antibodies against the plaque proteins desmoplakin I and II, plakoglobin, and plakophilin 1, we have found that these occur in most, if not all hair follicle desmosomes, whereas plakophilin 2 was absent, except in the basal cells of the outer root sheath, where a weak reactivity was found. By contrast, the desmosomal cadherins were mostly differentially synthesized, displaying a complicated map. While desmocollin Dsc3 was detected in all cell types examined, Dsc1 was detected only in the outer root sheath companion cell layer and the inner root sheath, and Dsc2 showed practically a mutually exclusive presence. Desmoglein Dsg2 was observed in basal cells of the outer root sheath as well as in the central cell layers of the subinfundibular outer rood sheath, matrix cells and trichocytes, in partial overlap with the otherwise different immunopositive reactions of Dsg1 and Dsg3. We have also determined when these proteins are synthesized during fetal hair follicle development. The differential molecular composition of desmosomes is discussed in relation to possible functional differences between the individual cell types.

The distribution of the desmosomal protein, plakophilin 1, in human skin and skin tumors

Desmosomes are predominant among the types of plaque-bearing adhering junctions found in human skin. These structures contain a set of desmosomal cadherins and cytoplasmic plaque proteins, the synthesis of which is differentiation dependent. As plakophilin 1, a member of the armadillo gene family, is an important accessory desmosomal plaque protein, we raised several monoclonal antibodies specific for this protein and applied immunohistochemical and immunoblotting procedures to study the distribution of plakophilin 1 in desmosomes in adult and fetal skin, psoriatic epidermis, various epithelial skin tumors, and keratinocyte sheets grown in culture. In epidermis, the spinous layers were prominently immunostained by plakophilin 1 antibodies, whereas the basal cell layer was only weakly stained and the stratum corneum was entirely unstained. The staining observed in psoriatic epidermis was somewhat heterogeneous. In hair follicles, the outer root sheath (ORS) was delineated in its suprabasal cell layers, with variable staining in its upper and lower parts. All basal cells of the ORS remained unstained, as did upper inner root sheath (IRS) and matrix cells of lower bulb. In eccrine sweat glands, the reaction was confined to inner dermal ductal cells, with the acini remaining unstained. The desmosomal immunostaining observed in basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) was very heterogeneous: In general, junctions in well-differentiated stratified tumor regions were more intensely stained than sections of poorly differentiated and invasively growing BCCs and SCCs. Plakophilin 1 was also prominent in the desmosomes of keratinocyte sheets grown in culture. The cell type-specific, i.e., differentiation-dependent, distribution of desmosomal plakophilin 1 is discussed in relation both to the stratification of the cutaneous epithelia and to tumor differentiation and growth.