An unusual histologic variant of necrobiotic xanthogranuloma.

Necrobiotic xanthogranuloma (NXG) usually shows a stereotypical histopathologic presentation. However, few unusual cases have been published. We present a patient with NXG showing exceptional histopathologic features. NXG in our patient presents with exclusively dermal granulomatous inflammation mimicking interstitial granuloma annulare. Not only subcutaneous involvement, but also, evident zones of degenerated collagen, foam cells, and cholesterol clefts were missing. Moreover, the case shows overlaps with recently published granulomatous scleromyxedema. Some common clinical and histopathologic features of NXG and scleromyxedema might be based on shared underlying paraproteinemia.

Erythema elevatum diutinum - a chronic leukocytoclastic vasculitis microscopically indistinguishable from granuloma faciale?

BACKGROUND: As the sequential inflammatory changes are the same in erythema elevatum diutinum (EED) and granuloma faciale (GF), histopathologic distinction may be difficult. METHODS: All available cases from 1998 to 2009 with the diagnosis of EED and GF were collected and reviewed, both clinically and histopathologically. Nine cases of EED and 41 cases of GF were reviewed in a blinded fashion using a checklist of 26 histopathologic criteria. RESULTS: Only four of the evaluated criteria showed differences between GF and EED. High density of the infiltrate was noted in 97% of cases of GF but only in 56% of cases of EED. Eosinophils were the predominant cell type in 59% of cases of GF but in none of the cases of EED. Plasma cells were more frequent in GF (64%) than in EED (22%), and granulomas were never found in GF but in 22% of EED. A zone of perijunctional sparing (Grenz zone) was observed in about three quarters of the cases in both the groups. CONCLUSIONS: The histopathology of GF and EED is very similar and overlapping. The presence of a Grenz zone and patterned fibrosis does not distinguish the two diseases. However, granulomatous nodules are only seen in EED, and a predominance of eosinophils in the infiltrate favors a diagnosis of GF.

Clinical application of multiphoton tomography in combination with confocal laser scanning microscopy for in vivo evaluation of skin diseases.

Multiphoton tomography (MPT) is an in vivo imaging technique with very high spatial resolution and efforts are made to combine MPT with other non-invasive imaging methods. The goals of the present study were the description of the features of different dermatological entities as seen in MPT and confocal laser scanning microscopy (CLSM) comparison of these two novel techniques and the 'classical' diagnostic measures visual inspection, dermoscopy and histology with respect to the strengths and weaknesses of the different methods and the potential benefit from their combined implementation. After study approval by the local Ethics Committee, 47 patients (31 male, 16 female, age range: 24-88 years) were recruited from the Department of Dermatology of the University Hospital Jena. In this work, we present an illustrative selection of eleven cases from a clinical study combining in vivo MPT with in vivo CLSM. The patients presented with a broad range of dermatological disorders including seborrheic keratoses, angioma, actinic keratoses, melanocytic nevi, malignant melanoma, psoriasis, pemphigus vulgaris and scarring. Both methods, CLSM and MPT, were found to be suitable for in vivo imaging of superficial skin layers and may therefore be useful in dermatological practice for the diagnosis of skin diseases. However, both methods differ in their technical and physical principles. Thus, despite of many similarities concerning the morphological presentation of cells and tissues, important differences are recognized. Synergies of the combination of CLSM and MPT may be obtained by combined implementation in order to benefit from the fast overview given by CLSM and the detailed imaging of skin structures by MPT.

Non-invasive imaging techniques in the diagnosis of skin diseases.

INTRODUCTION: In recent years, there has been an increasing interest in non-invasive imaging techniques in clinical and investigational dermatology. Besides the growing number of biophysical methods for the assessment of skin properties, novel imaging tools have emerged and classical imaging methods are substantially improved. AREAS COVERED: This review focuses on well established and some of the most promising imaging techniques for application in dermatology and cutaneous research. These comprise dermoscopy, sonography, confocal microscopy, multiphoton tomography and optical coherence tomography. Non-invasive imaging techniques are presented concerning their functional principles, the history of their development and their current clinical and research application. Advantages and limitations of each of the methods are discussed. EXPERT OPINION: Available non-invasive imaging techniques in dermatology show substantial differences concerning their limitations and opportunities, potential clinical applicability and practicability. Also, the current data available differ largely between these methods due to different levels of experience in research and clinical application. Future research will not only aim at improving current technical limitations, but also investigate the potential synergistic effects of combining two or more techniques in order to enhance their diagnostic impact.

In vivo measurement of the human epidermal thickness in different localizations by multiphoton laser tomography.

BACKGROUND: The in vivo measurement of epidermal thickness is still challenging. While ultrasound, optical coherence tomography and confocal laser microscopy are used with moderate success, this issue has not been addressed by multiphoton laser tomography. OBJECTIVES: In the present study, an in vivo measurement of four different morphometric epidermal parameters is performed. METHODS: Thirty healthy volunteers aged 21-82 years were included in the study after informed consent and approval of the local ethics committee. At the dorsal forearm and the dorsum of the hand, the thicknesses of the total epidermis, viable epidermis and stratum corneum and the depth of the papillary dermis were calculated from depth-resolved intensity curves after correlation with multiphoton images. RESULTS: We have shown consistently that in all age groups, the four morphometric parameters are significantly higher at the hand compared with the forearm, while there were no differences between age groups. This is consistent with most previous findings. CONCLUSION: The method presented here provides a novel in vivo investigation tool for the measurement of epidermal morphometric parameters that may be useful for the observation of epidermal changes over time in skin disorders, therapy side effects or in cosmetic science.

Depth-resolved measurement of the dermal matrix composition by multiphoton laser tomography.

BACKGROUND: In the last years, multiphoton laser tomography (MLT) has emerged as a promising tool for non-invasive diagnostics in dermatology and other medical specialties. The present work is dedicated to the question to what degree the measurement depth and the thickness of the epidermis influence the evaluation of dermal matrix composition and if recommendations for future measurement procedures can be given. METHODS: In a study group of 30 healthy volunteers aged 21-82 years multiphoton depth-resolved measurements of autofluorescence and second harmonics have been performed in order to evaluate the dermal matrix composition. RESULTS: Characteristic intensity curves depending on the penetration depth were derived and differences between age groups were found. CONCLUSION: With the present work we provide evidence for the accuracy of the measurement of dermal matrix composition by MLT and give detailed advice for the measurement procedure. Furthermore, we propose the use of depth-dependent emission intensity curves for monitoring of anti-aging treatment.

Intrinsic, solar and sunbed-induced skin aging measured in vivo by multiphoton laser tomography and biophysical methods.

BACKGROUND: Skin aging is accelerated by extrinsic factors, particularly actinic damage. Over the last decades, both clinical and pathological differences between intrinsic and actinic aging have been characterized. In this work, we aimed at quantifying skin aging by non-invasive in vivo methods. METHODS: Young healthy volunteers using indoor tanning facilities and aged people were compared with appropriate controls by measurements of skin elasticity with the Cutometer and the Reviscometer and by semi-quantitative evaluation of the dermal matrix composition by the multiphoton laser tomograph DermaInspect. RESULTS: We found differences between the sun-protected volar forearm and the dorsal side as well as between young and old test persons with all three methods. No significant differences were found between the skin of indoor-tanned test persons and control. Also, gender had no influence on the severity of skin aging. CONCLUSION: The most consistent results were obtained with the DermaInspect. The considerable inter-individual variation due to the cross-sectional design of the study may have disguised the factual skin damage caused by tanning beds.

Spectral fluorescence lifetime detection and selective melanin imaging by multiphoton laser tomography for melanoma diagnosis.

Multiphoton excited tissue fluorescence summarises the emission of all naturally occurring endogenous fluorescent bio-molecules with their often overlapping fluorescence spectra. Common fluorescence intensity measurements could not be utilised to distinguish between different fluorophores or metabolic states. To overcome this limitation, we investigated new procedures of selective melanin imaging and spectral fluorescence lifetime imaging in combination with high resolution multiphoton laser tomography. Overall 46 melanocytic lesions of human skin were analysed. We suggested that fluorescence light, detected in such a way, may yield additional information for melanoma diagnostics. Remarkable differences in lifetime behaviour of keratinocytes in contrast to melanocytes were observed. Fluorescence lifetime distribution was found in correlation with the intracellular amount of melanin. Spectral analysis of melanoma revealed a main fluorescence peak around 470 nm in combination with an additional peak close to 550 nm throughout all epidermal layers. Excitation at 800 nm shows a selectively observable fluorescence of melanin containing cells and offers the possibility of cell classification. Procedures of selective imaging as well as spectral fluorescence lifetime imaging by means of multiphoton laser tomography support diagnostic decisions and may improve the process of non-invasive early detection of melanoma.

Sensitivity and specificity of multiphoton laser tomography for in vivo and ex vivo diagnosis of malignant melanoma.

The incidence of malignant melanoma has shown a dramatic increase over the past three decades. Patient outcome and curability depend on early diagnosis. In vivo multiphoton laser tomography represents a recently developed diagnostic tool that allows non-invasive tissue imaging. We aim to demonstrate the application of multiphoton laser tomography for the in vivo differentiation and diagnosis of melanoma. Laser radiation in the near infrared spectrum was used to image endogenous fluorophores by multiphoton excitation. Eighty-three melanocytic skin lesions have been investigated. The results showed distinct morphological differences in melanoma compared with melanocytic nevi. In particular, six characteristic features of malignant melanoma were specified and statistically evaluated. Sensitivity values up to 95% (range: 71-95%) and specificity values up to 97% (range: 69-97%) were achieved for diagnostic classification. Logistic regression analysis was performed to identify the most significant diagnostic criteria. We found that architectural disarray of the epidermis, poorly defined keratinocyte cell borders as well as the presence of pleomorphic or dendritic cells were of prime importance. By means of this procedure accuracy values up to 97% were reached. These findings underline the potential applicability of multiphoton laser tomography in melanoma diagnosis of melanocytic skin lesions.

Changes in skin topography during hormone therapy.

The influence of female sex hormones on skin aging has repeatedly been investigated with contradictory results. In our study, the skin roughness of eight women receiving hormone therapy decreased significantly by approximately 15% in 12 months. Our results provide new evidence of the antiaging effect of female sex hormones.

Morphological skin ageing criteria by multiphoton laser scanning tomography: non-invasive in vivo scoring of the dermal fibre network.

BACKGROUND: Morphological changes in the dermal collagen and elastin fibre network are characteristic for skin ageing and for pathological skin conditions of the dermis. OBJECTIVES: To characterize pathological and physiological conditions by multiphoton laser scanning tomography (MLT) in vivo, it is necessary to investigate and identify morphological alterations related to ageing. METHODS: In vivo MLT was used to image two-photon excited autofluorescence (AF) and second harmonics generation (SHG) in human dermis of 18 volunteers of different ages. Criteria for the evaluation of age-dependent morphological changes in MLT images were fibre tension and morphology, network pattern, clot formation and image homogeneity. These criteria were weighted and a score was calculated. RESULTS: The resulting MLT-based Dermis Morphology Score is correlated with age (R2 = -0.90) and with the previously published SHG to AF Ageing Index of Dermis (R2 = 0.66). The two groups of young (age 21-38) and old (age 66-84) volunteers showed a significant difference in MLT score values (P < 0.001). CONCLUSIONS: We could demonstrate an in vivo relationship between morphological characteristics of human dermis assessed by MLT and age. The present score allows the semi-quantitative evaluation of specific morphological changes of the dermal fibre network in ageing skin by in vivo AF and SHG imaging. This method will be useful for diagnostics of pathological conditions and their differentiation from ageing effects.

In vivo assessment of human skin aging by multiphoton laser scanning tomography.

Changes of dermal collagen and elastin content are characteristic for skin aging as well as for pathological skin conditions. To evaluate these changes, we used in vivo multiphoton laser tomography to measure two-photon excited autofluorescence (AF) and second harmonic generation (SHG). We tested 18 patients of all ages and calculated the SHG-to-AF aging index of dermis (SAAID). We observed a negative relationship between the SAAID and age, which was accelerated for the female (n=7) subgroup. The current findings are the first in vivo demonstration of this relationship, and they show that specific characteristics of aged skin such as the ratio of extracellular matrix components collagen and elastin can be evaluated by in vivo AF and SHG measurements using near-IR femtosecond laser pulses.