Time-sequence histologic imaging of laser-treated cherry angiomas with in vivo confocal microscopy

How efficient is laser therapy for telangiectasias, spider veins, and cherry angiomas?-A study using dynamic optical coherence tomography

OBJECTIVES

A clinical study to investigate the effectiveness of pulsed dye laser (PDL) versus Nd:YAG laser in the treatment of telangiectasias, spider veins and cherry angiomas. Dynamic optical coherence tomography (D-OCT) was introduced as an innovative follow-up tool for evaluation of blood flow within superficial vessels and to allow visualization of morphological changes of the vasculature in vivo. The final aim of this study was to demonstrate a possible treatment benefit comparing both laser types.

MATERIALS AND METHODS

Vessel structures of 102 skin lesions were documented photographically and dermoscopically. Subsequently, lesions were imaged using optical coherence tomography before laser therapy (a), directly after the treatment (p) and after a follow-up 4-6 weeks after laser treatment. All lesions were treated using either a 595 nm PDL or a 1064 nm Nd:YAG laser. Two main vessel parameters, namely density and diameter, and their possible changes during follow-up were observed in 150/300/500 µm penetration depth using D-OCT and were subsequently compared between both treatment groups. Other analyzed vessel parameters were depth of the plexus, mean diameter, mean density, top edge of the vessel, columns, and spikes.

RESULTS

Both laser types are suitable options for the treatment of vascular skin lesions, with the most significant effect on cherry angiomas. PDL shows better results treating smaller vessels in upper skin regions, in comparison to Nd:YAG laser, achieving better results on deeper vessels, like spider veins. Using the applied laser settings, there was no statistically significant effect on telangiectasias.

CONCLUSION

D-OCT represents a new, noninvasive imaging method to evaluate blood flow and vessel morphology in the follow-up of telangiectasias, spider veins, and cherry angiomas, which underwent laser therapy.

Reflectance confocal microscopy in pediatric dermatology: A state-of-the-art review

Reflectance confocal microscopy is an innovative imaging modality, which noninvasively provides an optical image to aid in the diagnosis of skin lesions. While performing a skin biopsy for histopathologic analysis is the gold standard to definitively diagnose skin disease, this may prove to be more difficult in the pediatric population. This will occasionally necessitate sedation or general anesthesia as an approach, which carries a number of different risks. Reflectance confocal microscopy is an exciting new avenue in the support of diagnosing skin pathology, with the goal of improving pediatric patient tolerance and experience when examining epidermal and superficial dermal skin lesions. This review discusses the utility of reflectance confocal microscopy for pediatric dermatology patients pertaining to melanocytic and non-melanocytic skin neoplasms and inflammatory and infectious skin diseases in children.

Treatment Modalities for Cherry Angiomas: A Systematic Review

BACKGROUND

Cherry angiomas are benign vascular proliferations of endothelial cells associated with aging. Currently, no mainstay of treatment for these vascular anomalies exists.

OBJECTIVE

To review existing evidence-based therapies for the treatment of cherry angiomas.

METHODS

A literature search in May 2019 was performed with PubMed Database and Cochrane Library using the following terms: "cherry angioma," "senile hemangioma," "senile angioma," "cherry hemangioma," and "Campbell de Morgan spots."

RESULTS

Ten studies included in this systematic review reported laser therapy and nonlaser therapy as efficacious treatments for cherry angiomas. Among the laser therapies, pulsed dye laser (PDL) was preferred over potassium-titanyl-phosphate (KTP) and electrodessication (ED), based on decreased procedure-related pain. The neodymium-doped yttrium aluminum garnet (Nd:YAG) laser 1064 nm produced less pigmentary complications, whereas KTP and PDL risked pigmentary changes in darker-skinned individuals. Nonlaser therapies included cryotherapy, sclerotherapy, electrosurgery (i.e., ED, electrocoagulation), and radiofrequency ablation. No therapy proved to be superior.

CONCLUSION

A variety of therapeutic modalities exist for the treatment of cherry angiomas. However, a limited number of high-quality studies explored the efficacy of treatments and compared treatment modalities. Light-based methods such as argon, KTP, Nd:YAG, intense pulsed light, and PDL, along with non-light-based interventions such as cryotherapy, electrosurgery, and sclerotherapy effectively treated cherry angiomas.

Vascular diseases in the mature patient

Aging results in both anatomic and physiologic changes in the skin's structure and vascular system. These vascular changes result in a wide array of dermatologic findings, ranging from the benign to the highly morbid. Herein, we review the impact of both intrinsic and common extrinsic factors of aging on cutaneous vasculature and highlight the manifestations of microvascular, venous, arterial, lymphatic, and neuropathic alterations in the geriatric population.

The use of reflectance confocal microscopy for examination of benign and malignant skin tumors

Reflectance confocal microscopy (RCM) is a modern, non-invasive diagnostic method that enables real-time imaging of epidermis and upper layers of the dermis with a nearly histological precision and high contrast. The application of this technology in skin imaging in the last few years has resulted in the progress of dermatological diagnosis, providing virtual access to the living skin erasing the need for conventional histopathology. The RCM has a potential of wide application in the dermatological diagnostic process with a particular reference to benign and malignant skin tumors. This article provides a summary of the latest reports and previous achievements in the field of RCM application in the diagnostic process of skin neoplasms. A range of dermatological indications and general characteristics of confocal images in various types of tumors are presented.

Acute effects of local cold therapy in superficial burns on pain, in vivo microcirculation, edema formation and histomorphology

BACKGROUND

Local cold therapy for burns is generally recommended to relief pain and limit tissue damage, however, there is limited data of its physiological benefit. This study aimed to evaluate pathophysiological effects of cold therapy in superficial burn on microcirculation, edema formation, and histomorphology.

METHODS

In 12 volunteers (8f, 4m; aged 30.4±14.1 years) circumscribed superficial burn was induced on both hand back and either left untreated as control (control-group) or treated by local-cold-application (cold-treatment-group). Prior to burn (t0), immediately (t1), 15 min (t2), and 30 min (t3) following cold therapy, following parameter was evaluated using intravital-microscopy; epidermal-thickness (ET), granular-cell-size (GCS), individual-blood-cell-flow (IBCF), and functional-capillary-density (FCD).

RESULTS

Both ET and GCS increased significantly more in control-group and slightly in cold-treatment-group in t1, while turns to insignificant t2 onwards. IBCF and FCD raised up in control-group compared to dramatically decrease in cold-treatment-group in t1. In t2 both parameter remains in control-group and increased in cold-treatment-group. Comparison of both groups for IBCF and FCD indicates significant difference in t1 and t2, however, insignificant in t0 and t3.

CONCLUSIONS

Microcirculation, edema formation, and histomorphology of superficial burn has been significantly influenced through immediate cold therapy, however, this alterations are transient and turns to ineffective after 30 min.

The assessment of pulsed dye laser treatment of port-wine stains with reflectance confocal microscopy

BACKGROUND

Reflectance confocal microscopy (RCM) is a noninvasive technique for evaluating cutaneous lesions with cellular level resolution close to conventional histopathology. The aim of this study is to observe the vascular changes in Port-wine (PWS) lesions and assess the clinical efficacy of Pulsed Dye Laser (PDL) treatment by examining vessel diameter and density with RCM.

MATERIALS AND METHODS

Eleven adult patients with PWS, each had four test patches carried out with different pulse durations (1.5, 3, 6, and 10 ms), respectively; fluences of 9-12 J/cm²; and a spot size of 7 mm. The PDL treatment was repeated 3-5 times at a 2-month interval. Photographs and measurements with RCM were taken before each treatment and 2 months after the last treatment.

RESULTS

The PDL treatment exhibited increasing clearance with reducing pulse durations. Vessel diameters and densities were significantly decreased in the same pulse-duration groups after treatment. There was significant difference between 1.5 ms pulse-duration group and other pulse-duration groups in reducing blood vessel diameter at the depth of 150 μm.

CONCLUSIONS

RCM can be used to assess the clinical efficacy of PDL treatment.

Reflectance confocal microscopy allows in vivo real-time noninvasive assessment of the outcome of methyl aminolaevulinate photodynamic therapy of basal cell carcinoma

BACKGROUND

Photodynamic therapy (PDT) with methyl aminolaevulinate (MAL) is an approved noninvasive treatment option for basal cell carcinoma (BCC). In vivo reflectance confocal microscopy (RCM) is a noninvasive imaging technique that has proved useful for in vivo real-time cytomorphological analysis of BCC cells infiltrating the epidermis.

OBJECTIVES

  To investigate the use of in vivo RCM to assess the persistence of BCC cells surviving MAL-PDT.

METHODS

In vivo  RCM images of 20 biopsy-proven BCCs were taken before patients underwent a treatment cycle with MAL-PDT. Follow-up after 3months was performed using clinical examination, RCM and conventional dermoscopy. Treated areas also underwent a targeted 3-mm punch biopsy for standard haematoxylin and eosin histology stain to establish the clinical and instrumental correlation of the treatment outcome.

RESULTS

  Three months after PDT, clinical examination established that two out of 20 BCCs were persistent; dermoscopy found three out of 20 residual BCCs, but RCM showed that one of these lesions was a false positive, and showed persistent BCC foci in five out of 20 lesions. Histological analysis of targeted biopsies confirmed these results.

CONCLUSIONS

  RCM provided noninvasive, early detection of incipient recurrences of BCC after MAL-PDT. RCM findings steered targeted biopsies and surgical removal, or a new MAL-PDT, of these subclinical recurrences with minimal invasiveness.

Dermoscopy, confocal laser microscopy, and hi-tech evaluation of vascular skin lesions: diagnostic and therapeutic perspectives

Vascular skin lesions comprise a wide and heterogeneous group of malformations and tumors that can be correctly diagnosed based on natural history and physical examination. However, considering the high incidence of such lesions, a great number of them can be misdiagnosed. In addition, it is not so rare that an aggressive amelanotic melanoma can be misdiagnosed as a vascular lesion. In this regard, dermoscopy and confocal laser microscopy examination can play a central role in increasing the specificity of the diagnosis of such lesions. In fact, the superiority of these tools over clinical examination has encouraged dermatologists to adopt these devices for routine clinical practice, with a progressive spread of their use. In this review, we will go through the dermoscopic and the confocal laser microscopy of diagnosis of most frequent vascular lesions (i.e., hemangiomas angiokeratoma, pyogenic granuloma, angiosarcoma) taking into particular consideration the differential diagnosis with amelanotic melanoma.

The use of reflectance confocal microscopy for monitoring response to therapy of skin malignancies

SUMMARY

Reflectance confocal microscopy (RCM) is a new non-invasive imaging technique that enables visualizing cells and structures in living skin in real-time with resolution close to that of histological analysis. RCM has been successfully implemented in the assessment of benign and malignant lesions. Most importantly, it also enables monitoring dynamic changes in the skin over time and in response to different therapies, e.g., imiquimod, photodynamic therapy, and others. Given the often traumatic nature of skin cancer that affects both the physiology and the psychology of the patients, it is crucial to have methods that enable monitoring the response to treatment but that minimize the distress and discomfort associated with such process. This article provides a very brief overview of the fundamentals of RCM and then focuses on its recent employment as a monitoring tool in skin cancer and other pathologies that may require frequent follow-up.

In vivo reflectance confocal microscopy: usefulness for diagnosing hair diseases

BACKGROUND

Reflectance confocal laser scanning microscopy (R-CSLM) is a new diagnostic technique which allows visualization of "optical intersections" within the epidermis and superficial layers of the dermis. Outlines of cells and their architecture are imaged and may be analyzed both horizontally and vertically to the skin surface. The method proved useful in early melanoma detection. We evaluated the potential usefulness of this method in a short series of patients with hair diseases.

MAIN OBSERVATIONS

Two healthy persons and 6 patients with hair diseases (1 with alopecia areata, 1 with androgenic alopecia and 4 with genetic hair shaft abnormalities) were examined with the use of Vivascope 1500. In all patients one scalp location and one location in the mid forearm were evaluated. R-CSLM examination gave in all cases high quality images of the hair shaft intersections, at 1µm intervals, which allowed detailed analysis of the hair structure. Hair follicles could be partly visualized at a depth of up to 200µm, which allowed analysis of only superficial parts of the hair follicles. An additional hurdle was bright reflection within the follicular ostia, which decreased the perception of details in these images. Hair could be best visualized, when analyzed on flat surfaces. Receiving good quality images from convex surfaces on the scalp required additional effort from the patient (to not move) and from the physician (to obtain best possible fit of the "optic window" to the scalp).

CONCLUSIONS

These preliminary data show that R-CSLM may develop into a valuable tool in evaluation of hair shaft diseases. Further development is needed to apply this technique in abnormalities of the hair follicle and the perifollicular area.

Advances and short comings in the early diagnosis of melanoma

Malignant melanoma kills more people each year than any other skin cancer, with approximately 8000 lives lost and a cost of over 3 billion dollars annually in the US alone. Tumor depth is the most important prognostic factor in melanoma. Thus, early detection has the potential to diagnose melanoma when lesions are thinner, and to improve survival in primary melanomas. In this review, we discuss the implications, barriers, and advantages of melanoma screening, and describe the currently employed methods of detection, newly available modalities, and current areas of research. We also discuss the efficacy, advantages and disadvantages, and clinical practicality of each, and suggest various means of combining different methodologies as well as tailoring various strategies to individual patient needs.

Preliminary evaluation of benign vascular lesions using in vivo reflectance confocal microscopy

BACKGROUND

Reflectance confocal microscopy (RCM) is a novel noninvasive imaging technique for in vivo evaluation of cutaneous lesions at near-histologic resolution. The applicability of RCM for various neoplastic and inflammatory skin diseases has been shown, but a descriptive evaluation of different vascular lesions has not yet been performed.

OBJECTIVES

To define specific RCM criteria for congenital and acquired vascular lesions and to determine whether these criteria may assist in their differential diagnosis.

MATERIALS AND METHODS

Seven patients with a clinical diagnosis of vascular lesion, including spider angioma, venous lake, cherry angioma, pyogenic granuloma, port wine stain, angiokeratoma, and lymphangioma, participated in this study. Skin sites were systematically analyzed using RCM, and biopsy was obtained for clinically indeterminate lesions.

RESULTS

For each entity, characteristic RCM criteria could be identified and selected parameters correlated well to established histopathologic findings. The most relevant criteria included the diameter of the vessels and degree of vascular tortuosity or dilation. Additional findings such as flow velocity, inflammation, and disruption of the epidermal architecture could be documented.

CONCLUSION

The findings of this preliminary evaluation indicate that RCM may aid in the noninvasive characterization of inflammatory, proliferative, and ectatic vascular malformations in vivo.

Cherry Angiomas on the Scalp

Cherry angiomas are a common cutaneous vascular proliferation which manifests as single or multiple spots and occurs predominantly on the upper trunk and arms. They typically appear as round-to-oval, bright, red, dome-shaped papules and pinpoint macules measuring up to several millimeters in diameter. The histopathologic findings of a cherry angioma are consistent with a true capillary hemangioma, which is formed by numerous, newly developed capillaries with narrow lumens and prominent endothelial cells arranged in a lobular fashion in the papillary dermis. Herein, we report a case of multiple cherry angiomas on the scalp, an uncommon location for cherry angiomas.

Histometric and histomorphologic comparison of combustion and ambustion using in vivo reflectance-confocal microscopy

BACKGROUND

When combustion and ambustion induce a superficial injury, they are summarized as superficial burns, regardless of the underlying cause. Reflectance-confocal microscopy (RCM) allows noninvasive imaging of the human skin on morphological features. We hypothesized that combustion and ambustion have different histomorphological effects on the human skin.

METHODS

Superficial burns caused by combustion (CO-group, five females, three males; aged 26.8 +/- 14.2 years) and caused by ambustion (AM-group, four females, four males; aged 28.1 +/- 13.8 years) were evaluated 24 h after injury. The following parameters were obtained using RCM on injured and noninjured (control) site: horny layer thickness, epidermal thickness, granular cell size, basal layer thickness.

RESULTS

Compared with the controls (12.8 +/- 2.5 microm), horny layer thickness decreased significantly to 10.6 +/- 2.1 microm in the CO-group, whereas it increased significantly to 17.8 +/- 2.8 microm in the AM-group. The epidermal thickness did not differ significantly in CO-group (47.9 +/- 2.1 microm) and AM-group (49.0 +/- 3.1 microm), however, both increased significantly compared with the controls (42.7 +/- 1.6 microm). The basal layer thickness increased more in AM-group (17.0 +/- 1.2 microm) compared to CO-group (15.4 +/- 1.1 microm). Both differed significantly compared with their controls (13.9 +/- 0.9 microm). The granular cell size increased significantly in both groups compared to the controls (721 +/- 42 microm), however, a significantly higher increase was observed in CO-group compared to AM-group (871 +/- 55 microm vs. 831 +/- 51 microm).

CONCLUSIONS

RCM evaluates significant histomorphological differences in superficial burns caused by combustion and ambustion. The term "superficial burn" should consider the underlying cause and thus supplemented by the term "combustion" or "ambustion."

Melanoma early detection

Recognizing early forms of melanoma may have significant impact on decreasing mortality from this malignancy. As a result, multiple efforts have focused on developing new and improving current early detection strategies. These include educating patients about the importance of performing skin self-examination, increasing rates of complete skin examinations by physicians in the context of routine care, initiating mass screening campaigns, creating specialized skin cancer clinics, and developing better diagnostic tools through advances in technology. In this article, the current state of these efforts is reviewed.

Tonic inhibition of chemotaxis in human plasma

We found exaggerated chemotaxis in plasma treated with EDTA and thought that the EDTA might itself be inhibiting a tonic inhibitor(s) of chemotaxis. Our plasma fractionations suggested that evidence should be sought for a lipid moiety carrying this activity, and on spectrometry (LC-MS-MS together with GC-MS analyses), the biologically active but not the inactive fraction contained oleic and arachidonic acids. Because fatty acids are largely protein bound, we flooded plasma preparations with delipidated albumin, reasoning that it would bind enough fatty acids, including inhibitory ones, to counter their tonic inhibition. Indeed, we observed dramatic increases in chemotaxis. Hence, adding delipidated albumin to plasma has a similar effect to that of adding EDTA--amplification of the chemotactic response. Oleic acid in physiologic concentrations diminishes the magnifying effects of both EDTA and of delipidated albumin, and in fact diminishes the chemotactic response even without the presence of the amplifiers of chemotaxis. In contrast, arachidonic acid amplifies further the effect of EDTA but not of delipidated albumin, and this augmentation appears to be caused by an EDTA-dependent enrichment of the chemotactic gradient with leukotriene B4 (LTB4). We conclude that oleic acid, the blood levels of which vary among individuals, is at least one tonic inhibitor of chemotaxis in plasma.

Skin imaging with reflectance confocal microscopy

Confocal microscopy is a new imaging modality for noninvasive real-time tissue imaging with high resolution and contrast comparable with conventional histology. Application of this technology to skin imaging during the last decade has been an exciting advance in dermatology, allowing a virtual widow into living skin without the need for a conventional biopsy or histologic processing of tissue. High-resolution noninvasive skin imaging with confocal microscopy has potential broad applications in the clinical and research arenas, including differentiating between benign and malignant skin lesions, tumor margin mapping, monitoring response to medical or surgical treatments, and pathophysiologic study of inflammatory processes.

Differentiation of superficial-partial vs. deep-partial thickness burn injuries in vivo by confocal-laser-scanning microscopy

OBJECTIVE

The current determination of burn depth is based both on a visual and clinical assessment. Confocal-laser-scanning microscopy (CLSM) enables in vivo histomorphological images. We hypothesized that CLSM can differentiate superficial-partial vs. deep-partial thickness burns on a histomorphological level.

METHODS

Thirty-eight burn wounds in 14 patients were clinically divided in three groups from superficial (group 1), superficial-partial (group 2) to deep-partial (group 3) thickness burns. CLSM was performed with the Vivascope 1500 (Lucid Inc., Rochester, NY, USA) 24h after burn. The following parameters were assessed: cell size of the granular-layer, thickness of the basal-layer, minimal thickness of the epidermis and number of perfused dermal papillae.

RESULTS

Superficial burns resulted in a significant increase of the cell size of the granular-layer and a higher increase of the minimal thickness of the epidermis as in superficial-partial thickness burns. The granular-layer in partial thickness burns was destroyed. Superficial burns had an increased thickness of the basal-layer; in superficial-partial thickness burns the basal-layer was partly destroyed with complete destruction in deep-partial thickness burns. In superficial burns the perfused dermal papillae were increased significantly, while decreased in superficial-partial thickness, and completely destroyed in deep-partial thickness burns up to a depth of 350 microm.

CONCLUSIONS

In vivo confocal-laser-scanning microscopy can differentiate superficial-partial vs. deep-partial thickness burns on a histomorphological level.

Real-time imaging and characterization of human breast tissue by reflectance confocal microscopy

Real-time technologies can increase the efficiency of obtaining informative biopsies and accelerate interpretation of biopsy pathological review. Cellular aberrations inherent to cancer cells, including nuclear size, can currently be detected, but few technologies are available to evaluate adequacy of specimens in real time. The aims of this study are: 1. to determine if near-infrared reflectance confocal microscopy (RCM) can be used to assess epithelial/stromal content of core needle breast biopsy samples in real time, 2. to determine if epithelial cell nuclear size can be measured on RCM images, and 3. to test if RCM images can be accurately read for presence/absence of histologically relevant features of malignancy. Breast biopsies are obtained following a medically indicated breast core needle diagnostic biopsy for RCM examination. Acetic acid is used as a contrast agent to visualize structures within breast tissue. Structures are identified and optically serially sectioned, and digital images are cataloged. Relative amounts of epithelial, fatty, and collagenous tissue are determined. RCM biopsies are formalin-fixed and stained for hematoxylin and eosin (H and E) comparison with RCM images. RCM data are comparable to data from H and E sections. Epithelial cell nuclear size is measured on stored digital RCM images. We compare RCM and H and E images from 16 patients and 25 core needle biopsy samples.

Stratum corneum architecture of reconstructed human skin models monitored by fluorescent confocal laser scanning microscopy

Fluorescence confocal scanning laser microscopy (CLSM) using a handheld scanner, was performed to visualize the microscopic architecture of stratum corneum (SC) of the three reconstructed human epidermal (RHE) models: EpiDermTM (MatTek Corporation, Ashland, MA), EPISKIN® (EPISKIN SNC, Lyon, France) and SkinEthic® (SkinEthic Laboratories, Nice, France). To compare the differences between the SC structure of the RHE models and human SC, experiments were also performed on normal human epidermis in vivo. Sodium fluorescein stained skin cultures and human skin were imaged continuously using the confocal laser microscope Stratum, Optiscan. Fluorescein was excited at 488 nm and the fluorescent emission was detected at > 505 nm. In each experiment, a series of representative images of each visualized layer of the RHE models and human SC was collected. Our early observations confirmed that the reconstructed human skin models closely resemble human SC. After improving the experimental conditions, the method might be used for studying the effects of topically applied compounds e.g. pharmaceuticals and cosmetic to the SC.

In vivo confocal scanning laser microscopy in dermatology

The need to improve the diagnostic accuracy and sensitivity for skin tumours has led to the development of new non-invasive, in vivo techniques including ultrasound, dermoscopy, digital photography, confocal scanning laser microscopy, magnetic resonance imaging and optical coherence tomography. Of all these in vivo techniques, only confocal scanning laser microscopy allows for the examination of the epidermis and papillary dermis at a resolution approaching histological detail. This review article looks at some of the most important applications of this new technology, highlighting its qualities and limitations.

Reflectance confocal microscopy of pigmented basal cell carcinoma

BACKGROUND

Reflectance confocal microscopy (RCM) is a high-resolution imaging tool for in vivo noninvasive evaluation of skin lesions.

OBJECTIVE

We sought to describe the relevant RCM features for pigmented basal cell carcinoma (BCC).

METHODS

Pigmented skin lesions with a differential diagnosis of pigmented BCC were imaged using dermoscopy and RCM, followed by excision for histologic analysis.

RESULTS

RCM demonstrated aggregations of tightly packed cells with palisading, forming cordlike structures and nodules with irregular borders and variable brightness; these represented nests of pigmented basaloid tumor cells on histopathology, and blue-gray ovoid areas on dermoscopy. These tumor nests were associated with bright dendritic structures, identified histologically as either melanocytes or Langerhans cells, together with numerous bright oval to stellate-shaped structures with indistinct borders representing melanophages, and with highly refractile granules of melanin.

LIMITATIONS

The pigmented BCCs imaged in this study were predominantly nodular; a different set or additional criteria may be necessary for detection of infiltrative and metatypical BCCs.

CONCLUSION

RCM may permit in vivo diagnosis of pigmented BCC.

Terapia fotodinámica en dermatología

Photodynamic therapy (PDT) is a therapeutic modality based on the photooxidation of biological materials induced by a photosensitizer, which selectively locates itself in certain tumorous cells or tissues, so that when illuminated by a light of the right length and at a sufficient dose, these cells are destroyed. In dermatology, PDT with topical 5-aminolevulinic acid or 5-methyl aminolevulinate is very effective in the treatment of actinic keratoses, basal cell carcinomas and Bowen's disease. In addition, very promising results have been obtained in inflammatory pathologies like morphea or sarcoidosis, infections like warts, and cosmetic processes such as photoaging, among others. This article reviews the most significant aspects of PDT in dermatology. First of all, we will review the basic fundamentals of photodynamic treatment. Next, we will outline its clinical applications in dermatology, both in oncological applications and all those dermatological processes in which PDT may play a role in their management. We will also discuss its promising cosmetic application in the treatment of photoaging. We will complete the review with photodiagnosis and the different non-invasive ways to monitor the effectiveness of PDT.

Fluorescence fibre-optic confocal microscopy of skin in vivo: microscope and fluorophores

BACKGROUND/AIMS

Fibre-optic confocal imaging in vivo is a new approach in the assessment of human skin. The objective is to describe a novel instrument and its operation and use in combination with fluorophores.

METHODS

The Stratum is a fibre-optic fluorescence confocal microscope especially developed for the study of skin and mucous membranes. The system is flexible and any body site can be studied with a hand-held scanner. The light source is a 488 nm argon ion laser. Horizontal (en face) images of the epidermis and outer dermis are produced with cellular resolution. Magnification is approximately 1000 x . Fluorescein sodium is routinely used as fluorophore (intradermal injection or application to the skin surface). This fluorophore is safe for human use in vivo, but other substances (rhodamine B, Acridine Orange, green fluorescent protein, curcumin) have also been studied.

RESULTS

The instrument produces sharp images of epidermal cell layers from the epidermal surface to the sub-papillary dermis, with sub-cellular resolution. The scanner is flexible in use. The technique of intradermal fluorophore injection requires some skill.

CONCLUSIONS

We consider this fibre-optic instrument a potentially important tool in skin research for non-invasive optical biopsy of primarily the epidermis. Present use is focussed on research applications, where the fluorophore distribution in the skin may illustrate morphological changes in the epidermis.

Selective photothermolysis of blood vessels following flashlamp-pumped pulsed dye laser irradiation: in vivo results and mathematical modelling are in agreement

Laser therapy using the pulsed dye laser is the standard treatment for port-wine stains (PWS). But the mechanism of action has not been elucidated completely, yet. The dorsal skin-fold chamber model in hamsters was used to investigate the effects of laser treatment (lambda(em)=585 nm; pulse duration: 0.45 ms; fluence: 6 J per cm2) on blood vessels. Vessels (n=3394) were marked with FITC dextran (MW 150 kDa) and diameters (2-186 microm) were measured using intravital fluorescence microscopy up to 24 h following irradiation. Histology (H&E, TUNEL, CD31) was taken 1 or 24 h after irradiation. The experimental results were compared with the predictions of a mathematical model based on the finite-element method. Following irradiation treatment the number of unperfused vessels decreases with decreasing vessel diameter in vivo. Histology indicated a restriction of tissue injury to the irradiated area after 1 h. Blood vessels contained aggregated red blood cells. After 24 h tissue damage occurred also outside the irradiated area and thrombus formation was visible. These results were in agreement with the mathematical calculations. In addition to initial physical effects after pulsed dye laser treatment delayed biological processes contribute significantly to the reduction of perfused blood vessels. Because of incomplete photocoagulation of smaller blood vessels (diameter 2-16 microm) a complete bleaching of PWS seems to be unlikely.

Sensitivity and specificity of reflectance-mode confocal microscopy for in vivo diagnosis of basal cell carcinoma: a multicenter study

BACKGROUND

The current standard diagnostic procedure for basal cell carcinoma (BCC) is histologic examination after invasive biopsy. Reflectance-mode confocal microscopy (RCM) offers noninvasive high-resolution imaging of human skin in vivo.

OBJECTIVE

The objective of this study was to explore the sensitivity and specificity of RCM for diagnosis of BCC.

METHODS

This was a retrospective study of RCM images from 4 institutions of 152 skin lesions representing a variety of benign and malignant diagnoses. These 152 lesions were examined clinically, with biopsies recorded for all the 83 BCCs detected. Based on a previous study, a set of 5 histologically correlated confocal imaging criteria for diagnosing BCC was established, eg, the presence of elongated monomorphic nuclei. Blinded retrospective analysis of the images from the 152 lesions was carried out by a single novice reviewer to determine the sensitivity and specificity of these 5 RCM criteria for diagnosing BCC. The accuracy of combining the probability of BCC based on examination of clinical photographs with the predicted probability of BCC based on confocal criteria was also evaluated.

RESULTS

The presence of two or more criteria is 100% sensitive for the diagnosis of BCC, and with 4 or more RCM criteria present the specificity was 95.7% and sensitivity was 82.9%. These results were found to have little variability across study sites and across BCC subtypes. The combination of RCM with photography-based predictions of clinical probability of BCC significantly improved the accuracy for noninvasive diagnosis of BCC.

CONCLUSION

RCM offers a sensitive and specific tool for the noninvasive diagnosis of BCC in vivo.

Diagnostic Applicability of In Vivo Confocal Laser Scanning Microscopy in Melanocytic Skin Tumors

In vivo confocal laser scanning microscopy (CLSM) represents a novel imaging tool that allows the examination of skin morphology in real time at a resolution equal to that of conventional microscopes. The aim of the study was to test the applicability of CLSM to the diagnostic discrimination of benign nevi and melanoma. five independent observers without previous experience in CLSM received a standardized instruction about diagnostic CLSM features. Subsequently, 117 melanocytic skin tumors (90 benign nevi and 27 melanoma), imaged using a commercially available, near-infrared, reflectance confocal laser scanning microscope, were evaluated by each observer. Overall, sensitivity of 88.15% and specificity of 97.60% was achieved by the five observers. Logistic regression analysis revealed that mainly cytomorphology, architecture and keratinocyte cell borders should be taken into account for diagnostic decisions. Remarkably, using the presence or absence of monomorphic melanocytes as a single diagnostic criterion, the classification results with a sensitivity of 98.15% and a specificity of 98.89% were superior to the intuitive, integrative judgement of the observers. This first sensitivity and specificity study with CLSM has yielded promising results. CLSM provides new and useful information to the clinician diagnosing melanocytic skin tumors.

Changing paradigms in dermatology: confocal microscopy in clinical and surgical dermatology

The current practice of pathology and dermatopathology depends upon the evaluation of tissue in some manner extirpated from the patient and then processed and stained. While high resolution of detail can be accomplished by this method, there are certain risks and disadvantages. Recent imaging techniques now allow for a potential of achieving noninvasive high-resolution analysis of lesions in situ in the patient. Of these, Reflectance mode confocal microscopy offers the highest resolution imaging comparable to routine histology. Being entirely non invasive, skin can be observed in its native, dynamic state. This chapter will review the fundamentals of in vivo confocal imaging and the clinical applications in general and surgical dermatology.

Time and depth resolved visualisation of the diffusion of a lipophilic dye into the hair follicle of fresh unfixed human scalp skin

Visualising the penetration pathway of a lipophilic model dye into the hair follicle of fresh unfixed human skin would facilitate optimisation of drug formulations for local delivery to the pilosebaceous unit. A block of fresh human scalp skin was mechanically fixed in a newly designed combination of cutting device/on-line diffusion cell, manual cross-sectioned perpendicular to the skin surface and sealed to create the donor and acceptor compartment. The donor phase consisted of a saturated solution of Bodipy FL C(5) in a citric acid buffer solution. Images were obtained on-line by confocal laser scanning microscopy (CLSM) every 30 min for 16 h. For each time point and each skin region relative intensity values were calculated. The on-line visualisation showed a fast diffusion of the label into the gap of the hair follicle followed by a fluorescent staining in the gap itself. The data strongly indicate that the fluorescence in the cuticle originates mainly from the dye of the gap and not from the surrounding epidermis. The on-line visualisation provides a new and excellent tool to monitor simultaneous changes in distribution profiles in the various skin layers including the hair follicle. This information can be used to determine penetration pathways in the skin.

Hemangioma rubi no couro cabeludo

O hemangioma rubi (HR) é dermatose de origem vascular extremamente freqüente, acometendo mais de 75% da população acima de 70 anos de idade. Em geral compõe-se de lesões múltiplas,localizadas predominantemente no alto do tronco e braços. Clinicamente é caracterizado por lesões que variam desde máculas puntiformes até lesões papulosas com cinco milímetros de diâmetro. As mais novas são vermelhas, em tons vivos, e as mais antigas podem ser azuladas. O HR é de etiologia desconhecida. Histologicamente chama atenção uma neoformação de vasos capilares, que se tornam dilatados e com fenestrações em suas paredes. A membrana basal está muito espessada e existe abundante estroma de colágeno entre os vasos. O presente trabalho demonstra a alta incidência do HR no couro cabeludo Em amostra de 171 pacientes, sendo 85 homens e 86 mulheres, o autor observou que 123 deles (72%) tinham HR no couro cabeludo, localização em que o HR nunca foi descrito na literatura.

View of Normal Human Skin In Vivo as Observed Using Fluorescent Fiber-Optic Confocal Microscopic Imaging

Fluorescence confocal scanning laser microscopy, using a miniaturized handheld scanner, was performed to visualize the microscopic architecture of normal human epidermis in vivo. Fluorescein sodium (approximately 20 microL of 0.2% wt/vol) was administered via intradermal injection to normal skin on the volar forearm of 22 patients. The skin was imaged continuously from 1 to 15 min after injection. Fluorescein was excited at 488 nm and the fluorescent emission was detected at > 505 nm. In each subject, a series of images was collected at increasing depth, from superficial stratum corneum to papillary dermis. Features observed in confocal images were compared to those seen in hematoxylin- and eosin-stained sections of skin. The confocal images demonstrated the architecture of superficial skin in the horizontal plane. There was a transition in keratinocyte size, shape, and morphology with progressive imaging into the deeper epidermal layers. Superficial dermis and microscopic capillaries with blood flow were easily observed. The morphologic patterns associated with the major cell types of the epidermis were consistent with those known from conventional histology. We report the ability of in vivo fluorescence point scanning laser confocal microscopy to produce real-time, high-resolution images of the microscopic architecture of normal human epidermis using a noninvasive imaging technology.

Detection of intraepidermal malignant melanoma in vivo by confocal scanning laser microscopy

The early detection of malignant melanoma remains challenging for physicians. New techniques are being explored in order to improve diagnostic accuracy. Confocal scanning laser microscopy (CSLM) represents one such novel imaging modality. It allows in vivo microscopic analysis of skin lesions at a level of resolution approaching histological detail. Therefore, interpretation of optical sections represents in principle a histopathological analysis. Pigmented lesions are particularly amenable to examination by CSLM, since melanin pigment provides endogenous contrast, facilitating the recognition of melanocytes and their distribution within the epidermis. As a first step to explore the use of CSLM in the detection of melanoma, we sought to determine whether images obtained by CSLM are suitable for analysis by established histopathological criteria for the diagnosis of melanoma. We examined five pigmented lesions clinically suspicious for melanoma from five individual patients. Following imaging by CSLM, the clinical lesions were excised for examination by conventional histology. The melanocytes in the confocal images were recognized within the epidermis by their bright cytoplasmic signal intensity. They were round to oval in shape and frequently showed dendritic processes of various lengths. Confocal images of melanoma showed an increased number of intraepidermal melanocytes in solitary units at all layers of the epidermis, including the upper spinous and granular cell layers. Our results demonstrate that intraepidermal melanoma can be recognized by CSLM through analysis of the intraepidermal growth patterns of melanocytes using the same criteria as established for conventional histology. Thus, the application of CSLM represents a new tool for non-invasive screening of intraepidermal pigmented lesions in vivo and offers the opportunity to bring histopathological analysis to the bedside.

Morphologic features of melanocytes, pigmented keratinocytes, and melanophages by in vivo confocal scanning laser microscopy

Confocal scanning laser microscopy (CSLM) represents a novel imaging technique for in vivo microscopic analysis of skin lesions at a level of resolution that allows morphologic analysis of microanatomic structures. We investigated the feasibility of recognizing the cellular constituents of pigmented skin lesions, such as pigmented keratinocytes, melanocytes, and melanophages, by CSLM. Fifteen pigmented lesions (five pigmented seborrheic keratoses, and 10 compound melanocytic nevi) from 15 patients were studied, as well as normal skin. After the clinical lesions were imaged by CSLM, they were biopsied or excised for examination by conventional histology for comparison of the morphologic features. In images obtained by CSLM, pigmented keratinocytes were seen as polygonal cohesive cells with variably bright granular cytoplasm. Melanocytes appeared as bright round, oval, fusiform, or dendritic cells. The architectural growth pattern of melanocytes could be analyzed. Melanocytes were identified by their nested growth pattern as aggregates of bright round to oval structures at the dermoepidermal junction or in the superficial dermis. Melanocytes were also recognizable as single cells along the dermoepidermal junction, usually separated from each other by a variable number of keratinocytes. Melanophages appeared as large bright plump cells with ill-defined cytoplasmic borders, usually located around or near vessels of the superficial dermis. Our results demonstrate that the cellular constituents of pigmented lesions can be recognized by CSLM. This technique sets a new paradigm for noninvasive quasihistologic examination of pigmented lesions in vivo and merits further evaluation for diagnostic use.