Handheld optical-resolution photoacoustic microscopy.

Optical-resolution photoacoustic microscopy (OR-PAM) offers label-free

Separating melanin from hemodynamics in nevi using multimode hyperspectral dermoscopy and spatial frequency domain spectroscopy.

Changes in the pattern and distribution of both melanocytes (pigment producing) and vasculature (hemoglobin containing) are important in distinguishing melanocytic proliferations. The ability to accurately measure melanin distribution at different depths and to distinguish it from hemoglobin is clearly important when assessing pigmented lesions (benign versus malignant). We have developed a multimode hyperspectral dermoscope (SkinSpect™) able to more accurately image both melanin and hemoglobin distribution in skin. SkinSpect uses both hyperspectral and polarization-sensitive measurements. SkinSpect's higher accuracy has been obtained by correcting for the effect of melanin absorption on hemoglobin absorption in measurements of melanocytic nevi. In vivo human skin pigmented nevi (N=20) were evaluated with the SkinSpect, and measured melanin and hemoglobin concentrations were compared with spatial frequency domain spectroscopy (SFDS) measurements. We confirm that both systems show low correlation of hemoglobin concentrations with regions containing different melanin concentrations (R=0.13 for SFDS, R=0.07 for SkinSpect).

Vascular structures in dermoscopy.

Dermoscopy is an aiding method in the visualization of the epidermis and dermis. It is usually used to diagnose melanocytic lesions. In recent years, dermoscopy has increasingly been used to diagnose non-melanocytic lesions. Certain vascular structures, their patterns of arrangement and additional criteria may demonstrate lesion-specific characteristics. In this review, vascular structures and their arrangements are discussed separately in the light of conflicting views and an overview of recent literature.

Vascular structures in dermoscopy

AbstractDermoscopy is an aiding method in the visualization of the epidermis and dermis. It is usually used to diagnose melanocytic lesions. In recent years, dermoscopy has increasingly been used to diagnose non-melanocytic lesions. Certain vascular structures, their patterns of arrangement and additional criteria may demonstrate lesion-specific characteristics. In this review, vascular structures and their arrangements are discussed separately in the light of conflicting views and an overview of recent literature.

Implications of ultrasound frequency in optoacoustic mesoscopy of the skin.

Raster-scan optoacoustic mesoscopy (RSOM) comes with high potential for in vivo diagnostic imaging in dermatology, since it allows for high resolution imaging of the natural chromophores melanin, and hemoglobin at depths of several millimeters. We have applied ultra-wideband RSOM, in the 10-160 MHz frequency band, to image healthy human skin at distinct locations. We analyzed the anatomical information contained at different frequency ranges of the optoacoustic (photoacoustic) signals in relation to resolving features of different skin layers in vivo. We further compared results obtained from glabrous and hairy skin and identify that frequencies above 60 MHz are necessary for revealing the epidermal thickness, a prerequisite for determining the invasion depth of melanoma in future studies. By imaging a benign nevus we show that the applied RSOM system provides strong contrast of melanin-rich structures. We further identify the spectral bands responsible for imaging the fine structures in the stratum corneum, assessing dermal papillae, and resolving microvascular structures in the horizontal plexus.

A congenital smooth muscle hamartoma masquerading as a reticulate vascular naevus.

Smooth muscle hamartoma (SMH) is a benign congenital or acquired hamartomatous lesion comprising a dermal proliferation of smooth muscle bundles. We report a case of congenital SMH with an unusual clinical appearance. A 3-year-old girl presented with an asymptomatic atrophic linear lesion on the posterior surface of her right thigh, which had been present since birth. The striking resemblance to a vascular lesion initially led to the erroneous clinical diagnosis of atrophic reticulate vascular naevus. However, a skin biopsy showed typical features of SMH. To our knowledge, SMH with linear configuration has only been described in two previous cases, and there are no previous reports of SMH with such a marked resemblance to a vascular lesion.

Intraocular biopsy using special forceps: a new instrument and refined surgical technique.

AIM: The aim was to investigate the Essen biopsy forceps as a new instrument and surgical approach for biopsy of intraocular tumours. Biopsy is indicated for assessment of any uncertain intraocular process or confirmation for presumed diagnosis before treatment. There is increasing interest for further genetic and immunocytological information in order to characterise the neoplasm, especially grading and prognosis of micrometastasis in uveal melanoma. The authors have developed a new surgical technique using special intraocular biopsy forceps. METHODS: Twenty patients with uncertain intraocular subretinal tumour underwent biopsies carried out using the special Essen biopsy forceps. Biopsies were obtained through sutureless 23-gauge three-port vitrectomy. A small retinotomy tumour specimen was taken by the forceps branches. For further processing, the specimens were flushed out into a sterile tube and then sent to pathologists. RESULTS: The prebioptical tumour had a mean thickness of 3.48 mm (1.1 to 9.8 mm). In all cases (n=20) biopsies (0.3-2.1 mm in size) were obtained, in 19 cases (95%) allowing precise histological and immunohistochemical typing of the lesions following cytoblock embedding. Uveal melanoma was diagnosed in 50% (n=10), choroidal metastasis in 15% (n=3) and choroidal naevus in 15% (n=3); other diagnoses (n=3) included choroidal haemangioma, B cell lymphoma and old subretinal haemorrhage. Apart from three patients with temporary punctual bleeding on the surface, there were no intra- and postoperative complications. CONCLUSIONS: Biopsy using special forceps is a promising new approach and precise surgical procedure. Especially for small intraocular tumours, this technique has the advantage in providing enough tissue for improved histological examination and presenting a low risk for complications.

Dermoscopic evaluation of vascular structures of various skin tumors in Japanese patients.

Dermoscopic analysis of skin tumor has been mainly focused on pigmented structures. Recently, several different morphological types of vessels were found to be well associated with pigmented or non-pigmented skin tumors in white subjects. Therefore, the recognition of such vascular structures has been applied for diagnostic purposes. As little statistical information on the various pigmented skin tumor vessels of Japanese patients has been reported, we therefore tried to evaluate the association between various vascular structures and 741 tumor lesions of Japanese patients. Vascular structures were dermoscopically recognized in 41 of 102 cases of melanoma, 104 of 119 basal cell carcinoma (BCC), 86 of 257 seborrheic keratosis (SK), 35 of 210 dermal and compound nevus (DN/CN), six of 12 squamous cell carcinoma (SCC) and 16 of 41 Bowen disease (BD). The structures of arborizing and glomerular vessels statistically revealed diagnostic specificity for BCC and BD, respectively, and hairpin vessels were helpful for differentiating SK from other pigmented tumors, as already reported in white patients. The most common vascular pattern observed in melanoma was the linear-irregular structure, but this pattern in Japanese patients had less diagnostic value than in white patients, because its sensitivity was not significantly higher than in SCC. The most remarkable differences between our study and previous reports with white patients were low frequency and sensitivity of dotted, comma and polymorphous vessels in lesions of melanoma, BCC and DN/CN; these vessels had less diagnostic value for Japanese patients. Finally, the frequency of vascular structures observed in melanoma rose along with the increase of the Breslow's tumor thickness, and 88% of melanomas with vascular vessels revealed tumor thicknesses of more than 2 mm.

Lymphatic vessel density is significantly increased in melanoma.

BACKGROUND: Melanoma is well known for its ability to involve regional lymph nodes in the early stage. However, the presence of lymphangiogenesis in melanoma is still controversial due to lack of lymphatic-specific markers. The purpose of this study was to determine the intra- and peritumoral lymphatic vessel density (LVD) using a novel lymphatic vessel-specific marker D2-40 and compare it to general vessel density (GVD) as determined by CD31 immunostaining in a series of melanocytic lesions. METHODS: The intra- and peritumoral GVD and LVD were examined by immunohistochemistry using D2-40 and CD31 antibodies in a series of melanocytic lesions. RESULTS: We found significantly higher intratumoral LVD in melanomas as compared to either common acquired or dysplastic nevi (p < 0.01). Although peritumoral LVD in melanoma and malignant melanoma in situ was higher compared to nevi, the difference did not reach statistical significance (p = 0.059). There was no significant difference in GVD among the various groups of melanocytic lesions. CONCLUSIONS: Our results show that intratumoral LVD is significantly increased in melanomas compared to benign nevi. The higher intratumoral lymphatic density in invasive melanomas suggests that melanoma cells might promote lymphangiogenesis. In addition, assessment of intratumoral LVD may be potentially useful in the differential diagnosis of melanocytic lesions.

Naevus anaemicus with teleangiectatic vessels.

We describe a 20-year-old man with naevus anaemicus on the chest where, after dermabrasion of the epidermis, enlarged teleangiectatic dark-red vessels were seen within the previously pale area. They were clearly different from those seen on dermabrasion at this site in normal skin and in patients with vitiligo where the area is lighter red with only small punctual bleedings from arterial capillaries. The naevus anaemicus and a port-wine stain (naevus flammeus) in the same location is a phenomenon of vascular twin spotting, which was revealed when the epidermis was removed. The area was transplanted with thin epidermal grafts and healed within 2 weeks. One year later the naevus looked the same as before grafting. Much thicker grafts than those used by us will be needed, but they are not cosmetically acceptable.

An unusual hematopoietic proliferation seen in a nevus sebaceous.

Nevus sebaceous is a tumor of primary epithelial germ cells that is generally first noticed at birth. It is relatively quiescent until puberty when a variety of benign and potentially malignant tumors may arise within it. We describe a nevus sebaceous with immature fat cells, vascular ectasia, and extramedullary hematopoiesis that was present at birth. At 4 months, the immature adipose and hematopoietic elements, as well as the vascular changes, had resolved.

Blood flow compared in benign melanocytic naevi, malignant melanomas and basal cell carcinomas.

Histologically, increasing malignancy is reflected by increased tumour vascularization. We therefore assessed whether laser Doppler perfusion imaging might allow differentiation between different types of skin tumour. The perfusion patterns of 27 melanocytic naevi, 16 basal cell carcinomas and six malignant melanomas were examined with a laser Doppler perfusion imager before excision for precise diagnosis. Malignant melanomas were significantly more perfused than basal cell carcinomas and tended also to be more so than melanocytic naevi. Further, for the first time, the perfusion pattern of the entire tumour area was visualized two-dimensionally; it was higher in the centre of the tumours than at the periphery for malignant melanomas and melanocytic naevi but was the same throughout for basal cell carcinomas. Laser Doppler perfusion imaging can thus provide information to assist in the differential diagnosis of skin tumours. In addition, with increases in resolution of the technique such data may well become steadily more useful in the future.

Value of high-frequency US for preoperative assessment of skin tumors.

The purpose of this study was to evaluate the accuracy of high-frequency ultrasound (US) in the preoperative assessment of skin tumors. A US scanner with a 20-MHz probe was used to visualize and evaluate 70 skin lesions (38 clinically suspected melanomas and 32 suspected basilar cell carcinomas [BCCs]) before surgical resection. A US morphologic study and a Doppler analysis of vascularity were performed for each tumor. Of the 70 tumors, 62 were clearly visualized, including 19 melanomas, 12 nonmalignant nevi, and 31 BCCs. Most lesions were hypoechoic. In 13 of 19 proved melanomas, the difference between the histologic and US measurements was equal to or less than 0.2 mm. Vessels were visualized in melanomas with thicknesses greater than 3 mm. All BCCs were visualized, and in 29% of cases of BCC, tumor size at US was greater than that at clinical examination. High-frequency, high-resolution US is a simple, reliable, noninvasive method for accurate preoperative assessment of skin tumor dimensions. This technique allows surgical planning to be adapted and reexcision to be avoided. However, its role is limited in the differential diagnosis of malignant and benign skin lesions.

[Incident light microscopic characterization of vascular patterns in skin tumors]. / Auflichtmikroskopische Charakterisierung von Gefässmustern in Hauttumoren.

The search for vascular structures in skin tumors by incident light microscopy has revealed a surprisingly high proportion of vascularized tumours. Characteristic vascular patterns, in some cases highly tumour-specific, have been defined. The vascular structure is a valuable feature for characterization and differentiation of skin tumours, especially for amelanotic malignant melanoma. We propose a flowchart procedure for analysis and diagnosis of skin tumours using incident light microscopy, which appears to be valuable for advanced image analytic techniques.