Dermoscopy of Merkel cell carcinoma.

INTRODUCTION: Merkel cell carcinoma (MCC) is an aggressive cutaneous tumor whose clinical presentation, usually a pink nodule, is not specific. We aimed in this study to determine the dermoscopic criteria encountered in MCC. METHODS: From our image database we selected the patients diagnosed with MCC and scored the dermoscopic criteria shown by these tumors. RESULTS: Ten patients coming from three different academic hospitals were studied. Vascular structures were the more relevant dermoscopic features. In 8 out of 10 (80%) patients a polymorphic vascular pattern was seen, composed of milky-red clods/areas in association with one or more additional vascular structures. CONCLUSION: Although an overlap existed between the dermoscopic features observed in MCC and amelanotic melanoma, the presence of a polymorphous vascular pattern may constitute an additional clinical clue to accurately diagnose this rare tumor.

Embryonic vasculogenesis in nodular melanomas and tumour differentiation.

The relationship of vasculogenic mimicry to pigment in nodular vertical growth phase [VGP] cutaneous melanomas is assessed in this study. 10 nodules each from 27 tumors, 15 pigmented and 12 amelanotic were sampled in proportion to the pigment level. Serial frozen and paraffin sections subjected to HE, Reticulin, PAS to assess the vascular pattern; Dopa Oxidase and Immunopositivity for HMB45, LN5 [laminin 5] & integrin[α(5)ß(1)], and EM [electron microscopy] to identify Weibel-Palade bodies within endothelial cells. The vascular pattern, pigment and the immunopositivity was mapped to assess the percentage VM [vasculogenic sinusoids] vs INC [incorporated microvasculature]. In pigmented melanomas, INC from pre-existing stromal vessels is predominant. Amelanotic melanomas show embryonic vasculogenic mimicry, a self-propagating system of spaces within the sheets of tumors cells. Both INC and VM co-exist in tumors with both amelanotic and melanotic nodules. In areas with VM, loci of LN5 and α(5)ß(1) integrin positive cells appear within the proliferating columns, positivity in these cells suggesting a switch to a more aggressive form. Irregular spaces appear lined by tumor cells, with initial hemopoeitic activity, coalesce and interlink into tubular networks. Spaces lined by tumor cells extend into an intricate network which then connects with the angiogenetic system. The tumor cells lining the vasculogenic spaces are positive for LN5, α(5)ß(1) integrin. Statistically, INC is significantly higher in pigmented melanomas, whereas amelanotic melanomas show significantly higher VM. Pigmentation is correlated positively with INC and negatively with VM. INC and VM are negatively correlated with each other.

How to diagnose nonpigmented skin tumors: a review of vascular structures seen with dermoscopy: part I. Melanocytic skin tumors.

Dermoscopy is a noninvasive tool that can be helpful in the diagnosis of nonpigmented skin tumors. This is because dermoscopy permits the visualization of key vascular structures that are usually not visible to the naked eye. Much work has concentrated on the identification of specific morphologic types of vessels that allow a classification into melanocytic versus nonmelanocytic and benign versus malignant nonpigmented skin tumors. Among a broad spectrum of different types of vascular patterns, six main morphologies can be identified. These are comma-like, dotted, linear-irregular, hairpin, glomerular, and arborizing vessels. With some exceptions, comma, dotted, and linear irregular vessels are associated with melanocytic tumors, while the latter three vascular types are generally indicative of keratinocytic tumors. Aside from vascular morphology, the architectural arrangement of vessels within the tumor and the presence of additional dermoscopic clues are equally important for the diagnosis. This article provides a general overview of the dermoscopic evaluation of nonpigmented skin tumors and is divided into two parts. Part I discusses the dermoscopic vascular patterns of benign and malignant melanocytic skin tumors. Part II discusses the dermoscopic vascular patterns of benign and malignant nonmelanocytic nonpigmented skin tumors. In each part, additional special management guidelines for melanocytic and nonmelanocytic nonpigmented skin tumors, respectively, will be discussed.

How to diagnose nonpigmented skin tumors: a review of vascular structures seen with dermoscopy: part II. Nonmelanocytic skin tumors.

Nonmelanoma skin cancer refers to a broad class of tumors, including actinic keratosis, basal cell carcinoma, and squamous cell carcinoma, and as a group these are the most frequent cancers occurring in light skinned humans. In contrast to the rarity of amelanotic melanoma, nonmelanoma skin cancer commonly lacks pigmentation. Although these tumors rarely cause death related to metastases, they commonly destroy underlying tissues and should be removed at the earliest possible stage. Dermoscopy improves the clinical diagnosis of nonpigmented skin tumors by allowing the visualization of specific vascular structures that are usually not visible to the naked eye. Dermoscopic vascular patterns of several nonmelanocytic nonpigmented skin tumors, such as sebaceous hyperplasia, seborrheic keratosis, clear cell acanthoma, Bowen disease, or nodular cystic basal cell carcinoma are highly specific, allowing a ready diagnosis in most cases. Others, such as actinic keratosis, pyogenic granuloma, or uncommon adnexal tumors, may be difficult to differentiate even with the aid of dermoscopy. For this reason, general guidelines have been established to assist in making the most appropriate management decision. In the second part of this review of dermoscopic vascular structures of nonpigmented skin tumors, the dermoscopic patterns associated with benign and malignant nonmelanocytic skin tumors and recommendations for the management of these tumors will be discussed.

[Cancer-to-cancer metastasis: amelanotic melanoma into renal cell carcinoma]. / Karzinom-in-Karzinom-Metastasierung eines amelanotischen Melanoms in ein Nierenzellkarzinom.

HISTORY AND PHYSICAL FINDINGS: A 54-year old man was admitted because of motor aphasia, behavioral changes and weight loss and suffered from a widely disseminated cancer with unknown primary origin (CUP) syndrome. DIAGNOSIS: The autopsy revealed that he was affected by two malignant neoplasms simultaneously: an amelanotic malignant melanoma metastasizing into a localized renal cell carcinoma. CONCLUSION: Cancer-to-cancer metastasis is an exceedingly rare, but well documented phenomenon. This is the third reported case of a malignant melanoma as donor tumor spreading into a renal cell carcinoma. Well-vascularized and slowly growing renal tumors are typical recipients for cancer-to-cancer metastases. The amelanotic character of the melanoma exerted a special diagnostic challenge. Clinical and autopsy findings as well as the immunophenotypical features of the metastatic amelanotic melanoma (HMB-45, Melan-A/MART-1, S100) and the renal cell carcinoma are described with a review of the relevant literature.

Poppyfield bleeding: a new dermatoscopic sign and its histopathological background.

Dermatoscopy increases the accuracy of diagnosis of melanoma. An atypical vascular pattern may be an indicator of cutaneous malignant melanoma (CMM). During dermatoscopy of certain CMMs numerous ruby droplets of blood appear when the dermatoscope is pressed firmly against the lesion. The aim of this paper was to examine the histopathological background for this observation. CMMs from 8 patients showing the poppyfield sign, i.e. squirts of ruby blood droplets, were paired with 8 CMMs of equal Breslow thickness not showing this sign. The 16 CMMs were placed in an unsystematic sequence and presented to two dermato-pathologists who assessed the lesions independently for confirmation of Breslow thickness, Clark level, ulceration and presence of dilated tumour vessels. There was no disagreement between the pathologists' assessments. Age of the patients and Breslow thickness of the cutaneous malignant melanoma were similar in the two groups. All 8 poppyfield CMMs had dilated tumour vessels compared with 25% (2/8) of the non-poppyfield CMMs (p< 0.007). Histological ulceration was observed in all poppyfield CMMs and none of the non-poppyfield CMMs (p< 0.001). The poppyfield bleeding sign is a dermatoscopic clue to dilated tumour vessels. It may be a dermatoscopic reflection of increased vascular density described in primary CMMs compared with adjacent skin and may also reflect the presence of primitive vessels in CMMs displaying increased fragility.

Comparison of tumor blood perfusion assessed by dynamic contrast-enhanced MRI with tumor blood supply assessed by invasive imaging.

PURPOSE: To evaluate the potential of Gd-DTPA-based dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for providing high-resolution tumor blood perfusion images. MATERIALS AND METHODS: Xenografted tumors from two amelanotic human melanoma lines (A-07 and R-18) were used as preclinical models of human cancer. DCE-MRI was performed at a voxel size of 0.5 x 0.2 x 2.0 mm(3) with the use of spoiled gradient recalled sequences. We produced tumor images of E . F (where E is the initial extraction fraction, and F is perfusion) by subjecting the DCE-MRI data to Kety analysis, and then compared those images with images of tumor blood supply. We obtained high-resolution tumor blood supply images using the Bioscope silicon strip detector system to measure the uptake of Na(99m)TcO(4) in histological preparations. We assessed the global blood supply by measuring the tumor uptake of three freely diffusible blood flow tracers: (86)RbCl, [(14)C]IAP, and Na(99m)TcO(4). RESULTS: E . F was found to mirror the blood supply well in A-07 and R-18 tumors. The mean E . F differed between the A-07 and R-18 tumors by a factor of approximately 1.6, and this difference was similar to the difference in the global blood supply. The intratumor heterogeneity in E . F was significant for tumors of both lines, and this heterogeneity was similar to the intratumor heterogeneity in the blood supply. The intratumor heterogeneity in the blood supply differed slightly between the A-07 and R-18 tumors, and even this difference was mirrored by the E . F images. CONCLUSION: E . F images of xenografted tumors reflect blood perfusion. This implies that E . F may be a useful parameter for improving cancer diagnostics and individualizing cancer treatment. This possibility deserves to be investigated thoroughly in clinical studies.

Amelanotic/hypomelanotic melanoma: clinical and dermoscopic features.

BACKGROUND: Amelanotic malignant melanoma is a subtype of cutaneous melanoma with little or no pigment on visual inspection. It may mimic benign and malignant variants of both melanocytic and nonmelanocytic lesions. OBJECTIVES: To evaluate whether dermoscopy is also a useful technique for the diagnosis of amelanotic/hypomelanotic melanoma (AHM). METHODS: We conducted a retrospective clinical study of 151 amelanotic/hypomelanotic skin lesions from 151 patients with a mean age of 47 years (+/- 17.5 SD). Digitized images of amelanotic/hypomelanotic skin lesions were converted to JPEG format and sent by e-mail from the five participating centres. Lesions included 55 amelanotic/hypomelanotic nonmelanocytic lesions (AHNML), 52 amelanotic/hypomelanotic benign melanocytic lesions (AHBML), and 44 AHM, 10 (23%) of which were nonpigmented, truly amelanotic melanomas (AM). The 44 AHM lesions were divided into thin melanomas (TnM) 1 mm (15 cases), according to the Breslow index. Five clinical features (elevation, ulceration, shape, borders and colour) as well as 10 dermoscopic criteria (pigment network, pigmentation, streaks, dots/globules, blue-whitish veil, regression structures, hypopigmentation, leaf-like areas, multiple grey-bluish globules, central white patch) and eight vascular patterns (comma, arborizing, hairpin, dotted, linear irregular, dotted and linear irregular vessels, and milky-red areas) were evaluated in order to achieve clinical and dermoscopic diagnoses. Statistical analyses were performed with the chi2-test and Fisher's exact test, when appropriate. RESULTS: The most frequent and significant clinical features for TnM and TkM were asymmetry and ulceration (the latter only for TkM) compared with AHBML. Irregular dots/globules (62% vs. 35%; P

Hyperthermia induces T1 relaxation and blood flow changes in tumors. A MRI thermometry study in vivo.

Regional hyperthermia in combination with chemotherapy and/or radiotherapy has proven to be an effective treatment concept for locally advanced deep-seated tumors. Simultaneous MR-imaging could be a promising approach for therapy optimization. Purpose of this study was the in vivo investigation of temperature induced longitudinal relaxation time (T(1)) and blood flow changes in a tumor model. Using a 1.5 Tesla MR system, the T(1) sensitivity on temperature and the onset of tissue changes at temperatures >44 degrees C were investigated in muscle samples. Also, fourteen Syrian Golden Hamsters with amelanotic melanoma A-MEL-3 were examined during heating of the tumors. Temperature induced blood flow and T(1) changes were determined continuously during hyperthermia. Changes of T(1) correlated linearly with temperature over a wide range (27-44 degrees C) in the tissue sample. Tissue changes became notable above 44 degrees C. In the tumor model, relative changes of T(1) (unlike blood flow) showed linear correlation with temperature over the entire range of hyperthermia relevant temperatures (32-44 degrees C). For a low thermal dose, T(1) allows the assessment of temperature changes in tumors in vivo. At higher thermal doses, in addition to temperature changes, T(1) also shows tissue changes. Both temperature and tissue changes supply important information for hyperthermia.

Apoptosis and leucocyte-endothelium interactions contribute to the delayed effects of cryotherapy on tumours in vivo.

In dermatology, cryotherapy is commonly used to treat benign and malignant skin lesions. However, studies investigating the time-course of the direct and delayed effects on the microvasculature and subsequent tissue destruction are lacking. Amelanotic melanomas (A-Mel-3) were implanted into the dorsal skinfold chamber of Syrian Golden hamsters (n=51). Tumour and normal tissue were frozen to -20 masculine C (cooling rate 150 masculine C/min). Intravital fluorescence microscopy was performed to assess microvascular changes and leucocyte-endothelium interactions up to 24 h. The relative degrees of necrosis and apoptosis and the accumulation of leucocytes were investigated by histology and immunohistochemistry. Apoptosis was quantified using the TUNEL assay in combination with computer-assisted image analysis. After cryotherapy, red blood cell velocity (RBCV) decreased in postcapillary venules and tumour vessels, whereas functional vessel density (FVD) was significantly reduced in tumour vessels as compared with postcapillary venules. Leucocyte-endothelium interaction increased first in normal and tumour tissue, and then after 24 h leucocytes accumulated in normal tissue close to the tumour margin. Necrosis was induced in the cryolesions directly after freezing and remained constant over the entire observation period. In contrast, apoptosis increased in the periphery of the tumour tissue up to 24 h following cryotherapy. In conclusion, tissue destruction by cryotherapy is not only induced by direct necrosis and microvascular stasis, but also by the inflammatory infiltrate and subsequent apoptosis. This could be an important finding regarding the generation of an immune response.

Intratumor heterogeneity in perfusion in human melanoma xenografts measured by contrast-enhanced magnetic resonance imaging.

The perfusion in tumors shows substantial spatial heterogeneity compared to that in normal tissues. The aim of the present study was to evaluate the intratumor heterogeneity in perfusion in tumors of two amelanotic human melanoma xenograft lines, A-07 and R-18, grown intradermally in Balb/c nu/nu mice. A non-invasive contrast-enhanced magnetic resonance imaging method yielding results in absolute values was applied. The perfusion was determined in manually defined regions of interest, corresponding to a whole tumor or to subregions of a tumor. The mean perfusion and the intertumor heterogeneity in perfusion were similar for the two tumor lines. For whole A-07 tumors, the perfusion ranged from 0.089 mL/(g . min) to 0.20 mL/(g . min) [mean: 0.15 mL/(g . min)], and for whole R-18 tumors, from 0.030 mL/(g . min) to 0.17 mL/(g . min) [mean: 0.13 mL/(g . min)]. The intratumor heterogeneity, on the other hand, was estimated to be 6.4 times larger in A-07 tumors than in R-18 tumors. The highest perfusion values, up to 0.69 mL/(g . min), were found in subregions of A-07 tumors. The intratumor heterogeneity was substantially larger than the intertumor heterogeneity in A-07 tumors, whereas in R-18 tumors, the intratumor heterogeneity was similar to the intertumor heterogeneity. These observations imply that measurements of mean tumor perfusion may have limited value as a predictive assay for outcome of treatment.

Evaluation of microvascularization pattern visibility in human choroidal melanomas: comparison of confocal fluorescein with indocyanine green angiography.

BACKGROUND: The presence of specific microvascularization patterns (networks, parallel with and without crosslinking, silent) in histological sections of human choroidal melanomas has prognostic significance for survival. We showed previously in selected patients that the identification of these microvascularization patterns is possible in vivo by using confocal scanning laser indocyanine green angiography and that this technique is superior to fluorescein angiography using a conventional acquisition technique with a fundus camera. We now routinely use simultaneous confocal fluorescein/indocyanine green angiography to study microvascularization patterns in choroidal melanomas. The purpose of this study was to compare the visibility of tumor vessels and microvascularization patterns in fluorescein and indocyanine green angiography in simultaneous confocal series taken with the same instrument in a large prospective series of patients. PATIENTS AND METHODS: The simultaneously procured confocal fluorescein and indocyanine green angiograms of 50 patients with untreated choroidal melanomas (maximal apical height according to standardized A-scan between 2 and 8 mm) were studied for the visibility of tumor vessels and microvascularization patterns. At least one simultaneous confocal optical series (32 images in sequential depth order) during the early arterial venous phase was obtained per patient. RESULTS: Confocal forescein angiography disclosed signs of tumor vascularization in 12 (24%) of the 50 patients examined. However, in only 3 patients (6%) could microvascularization patterns be identified using confocal fluorescein angiography, and only in the very early arterial phase, which is often difficult to capture. In contrast, simultaneously obtained confocal indocyanine green angiograms disclosed tumor vessels in 47 (94%) of the examined 50 patients and microvascularization patterns could be identified in all of these cases. In 3 patients (6%) no tumor vessels could be detected within the tumor borders. CONCLUSION: This study demonstrates that confocal indocyanine green angiography images microvascularization patterns in choroidal melanomas better than fluorescein angiography, even when the images are acquired with the same technique. This can be explained with the different absorption, fluorescence and exudation characteristics of these dyes. In vivo imaging of these microvascularization patterns using confocal indocyanine green angiography offers the possibility of assessing the prognosis of choroidal melanomas without the removal of tissue.

Targeting of the tumor microcirculation by photodynamic therapy with a synthetic porphycene.

9-acetoxy-2,7,12,17-tetrakis-(beta-methoxyethyl)-porphycene (ATMPn) is a chemically pure substance with fast pharmacokinetics and superior photodynamic properties in vitro as compared to Photofrin. In this study the pharmacokinetics, photodynamic efficacy and tissue localization of ATMPn were investigated in vivo. Amelanotic melanomas (A-Mel-3) were implanted in dorsal skin fold chambers fitted to Syrian Golden hamsters. Fluorescence kinetics of ATMPn (1.4 mumol kg-1 b.w.i.v.; n = 8) were monitored by intravital microscopy. Quantitative measurements of fluorescence intensity were carried out by digital image analysis. For tumor growth studies 1.4 mumol kg-1 was injected 24 h (n = 3), 3 h (n = 3), 1 min (n = 6) and 2.8 mumol kg-1 1 min (n = 6) before PDT (Laser (630 nm) or lamp (600-750 nm), 100 mW cm-2, 100 J cm-2). Tumor volume was measured for 28 d. Solid tumors (n = 3) were excised 1 min after injection of ATMPn (2.8 mumol kg-1) and cryostat sections (20 mm) were analyzed by confocal laser scanning microscopy (CLSM) for tissue localization of the dye. Maximal fluorescence (mean +/- S.E.) arose in the tumor (94 +/- 7%) and surrounding host tissue (67 +/- 5%) 30 s post injection followed by a rapid decrease. Hardly any fluorescence was detectable 12 h after administration. Only PDT 1 min after injection of ATMPn was effective yielding 3/6 complete remissions (2.8 mmol kg-1, laser) and 6/6 complete remissions (2.8 mumol kg-1, lamp), respectively. One minute after injection the dye is primarily localized in the vascular wall of normal and tumor vessels as shown by CLSM. PDT at a time, when the dye is localized primarily in the tumor microcirculation, exhibits the best tumor killing effects showing that vascular targeting is effective in treating solid malignant tumors. ATMPn in liposomes makes administration and light irradiation in one session possible due to its fast pharmacokinetics. Thus, using ATMPn as a photosensitizer may provide more flexibility to perform PDT after surgical exploration and debulking as adjuvant therapy.

Photodynamic therapy-induced alterations in interstitial fluid pressure, volume and water content of an amelanotic melanoma in the hamster.

The effect of photodynamic therapy (PDT) on interstitial fluid pressure (IFP), tumour volume and water content was measured in melanomas grown in hamsters. Unlike control tumours, treated tumours exhibited a 40-60% increase in volume at 1, 3 and 6 h post PDT. IFP also increased at 1 and 3 h after PDT, but decreased to 50% of control value after 24 h, presumably as a result of PDT-induced microcirculatory impairment.

Amelanotic melanoma of the lung and brain with fenestrated intrinsic tumor capillaries.

Tissue from an amelanotic melanoma which involved the lung and brain was studied by electron microscopy. Endothelial fenestrae were found in the intrinsic tumor capillaries at both locations, a finding which does not appear to have been previously reported for amelanotic melanoma. Pitfalls in the diagnosis of this rare tumor are discussed.