Microcirculation architecture of melanocytic nevi and malignant melanomas of the ciliary body and choroid. A comparative histopathologic and ultrastructural study

Vascular Lakes in Uveal Melanoma and Their Association With Outcome

Purpose

Prognostic predictors in uveal melanoma (UM) consist of clinical, histomorphologic, and genetic features. Vascular lakes (VLs) are immature blood vessels within UM with unknown significance for metastatic risk.

Methods

A clinically well-phenotyped cohort of 136 hematoxylin and eosin–stained slides of UM enucleation specimens were retrospectively analyzed on scanned whole-slide images. These were annotated for VL in QuPath, assessing VL number and area. Using SPSS (V27.0), the Mann–Whitney U test and Cox regression were applied to evaluate whether there was any correlation between VL number and area within the tumor (VL-TA) compared with other prognostic parameters and patient survival times.

Results

UMs with monosomy 3 (M3) have significant differences in their VL numbers (P = 0.008) and VL-TA ratios (P = 0.002) compared with disomy 3-UM. Nuclear BAP1-negative (nBAP1^–) UMs have significant differences in their VL-TA ratio (P = 0.002) compared to nBAP1⁺ UMs. Survival times of patients with UM with epithelioid-celled tumors varied depending on their VL-TA ratio (P = 0.057). Similarly, in M3-UM, significant differences in survival (P = 0.009) were seen in patients, depending on VL number. Finally, patients with UM with shorter overall survival showed significant differences in their tumor VL-TA ratios (P = 0.043) and the number of VLs present (P = 0.002) than patients with UM who had longer survival.

Conclusions

Our pilot data suggest that VL-TA is an additional poor prognostic parameter in UM.

Translational Relevance

Digital analysis of UM can be easily performed to assess various prognostic parameters. Our pilot study demonstrates that UM-VL could be combined with other parameters to determine metastatic risk of patients with UM.

SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN SMALL CHOROIDAL MELANOMAS AND CHOROIDAL NEVI

PURPOSE

To evaluate the use of swept-source optical coherence tomography angiography to detect distinct vascular features in small choroidal melanomas and choroidal nevi.

METHODS

Patients with a choroidal nevus or a treatment-naïve choroidal melanoma were imaged with color fundus photography, ultrasound, and swept-source optical coherence tomography angiography (12 × 12 mm). High-risk features including overlying fluid, orange pigment, shaggy photoreceptors, acoustic hollowness, depth >2 mm, and basal diameter >5 mm were assessed. Optical coherence tomography angiography vascular markers included: choroidal vessel visualization, choroidal vessel depth, and choriocapillaris flow signal, assessed qualitatively by comparison with surrounding, unaffected choriocapillaris.

RESULTS

Twenty-nine lesions were included in this study, seven flat choroidal nevi, 17 elevated choroidal nevi, and 5 choroidal melanomas. Distinct vascular patterns were noted between flat nevi, elevated nevi, and small choroidal melanomas. Choroidal melanomas displayed two types of vasculature: "nevus-like" vasculature with straight parallel vessels and complex vasculature with vascular loops and crosslinking. Visualized choroidal vessels were significantly deeper in melanomas (110 µm) than elevated (84 µm) or flat nevi (70 µm). In a size-matched subanalysis of 5 elevated choroidal nevi and 5 choroidal melanomas, choroidal melanomas had increased mean choroidal vessel depth (P = 0.015), deepest choroidal vessel visualized (P = 0.034), and presence of a deep choroidal vessel >155 µm (P = 0.048).

CONCLUSION

Swept-source optical coherence tomography angiography may detect distinct vascular features in choroidal nevi and small choroidal melanomas.

[Results of optical coherence tomography angiography in choroidal melanoma]

Blood supply is known to be required for tumor growth and metastasis, and the formation of the tumor's own vasculature plays a critical role in the development of solid neoplasms. The method of optical coherence tomography angiography (OCTA) is considered promising for the study of angioarchitectonics.

PURPOSE

To evaluate the OCTA signs of choroidal melanoma (CM) depending on its sizes.

MATERIAL AND METHODS

The study included 24 patients with CM (24 eyes, of them with small CM - 22 eyes) aged 55.0±12.08 years (37 to 80 years old) with mean prominence of 2.35±0.87 mm (1.0 to 4.7 mm).

RESULTS AND DISCUSSION

Retinal vascular attenuation in the tumor area was observed in 21 eyes. Changes in angioarchitectonics in the area of CM localization can be detected at a thickness of 1 mm, and the tumor's own vasculature - starting with a thickness of 1.4 mm. The development of vascular changes in CM can be represented as follows: initially, with CM prominence of up to 1.4 mm, indirect signs of increased blood flow in the overlaying choriocapillaris layer are visualized, most likely due to its compression; as the tumor grows and its thickness increases in its most dominant part, the choriocapillaris layer is completely destroyed, which leads to reactive expansion of the choroidal capillaries along the layer's edges. This is manifested as attenuation of the vascular signal in the central part of the tumor and its intensification along its edges. In the meantime, collaterals begin to form in the deep vascular plexus of the retina. Later on, chaotic vascular arches begin to form in the inner layers of the choroid along the tumor edge; as the tumor grows, they anastomose with the retinal vessels. Identification of the tumor's own vessels in the deeper-lying layers is possible with tumor prominence of at least 1.4 mm. At the level of the deep choroidal layers, the tumor's vascular pattern is more consistent with the angiographic data and patterns of vasculogenic mimicry described in literature.

CONCLUSION

Changes in angioarchitectonics in the area of CM localization can be detected at a thickness of 1 mm, and the tumor's own vasculature - starting with a thickness of 1.4 mm. The vascular pattern at the level of the deep choroidal layers best corresponds to the reported angiographic picture and patterns of vasculogenic mimicry.

Imaging the Choroid: From Indocyanine Green Angiography to Optical Coherence Tomography Angiography

The choroid is the vascular structure nourishing the retinal pigment epithelium and the outer retina and it plays a key role in the homeostasis of the eye both under physiological and pathological conditions. In the last 20 years we have moved from "guessing" what was happening beyond the retinal pigment epithelium to actually visualize structural and functional changes of the choroid in vivo noninvasively. In this review we describe the state of the art of choroidal imaging, focusing on the multiple techniques available in the clinical and research setting including indocyanine green angiography, labeled-cells angiographies, optical coherence tomography (OCT), enhanced depth imaging, swept source OCT, and OCT angiography. In the first section of the article, we describe their main applications and the basic principles to interpret the imaging results. Increasing evidence suggests that the choroid is much more involved than we used to think in many pathological conditions from uveitis to intraocular tumors, from vascular diseases to age-related macular degeneration. All clinicians should hence know which is the most appropriate imaging investigation to explore the choroid in the disease they are dealing with and how to interpret the results. For this reason the second section of this review summarizes the best imaging approach and the most common findings visible on choroidal imaging in different diseases of the eye.

Is optical coherence tomography angiography helpful in the differential diagnosis of choroidal nevus versus melanoma?

PURPOSE

To describe the imaging features of choroidal nevus and melanoma using optical coherence tomography angiography, and evaluate the ability of this technique to establish the differential diagnosis based on the display of the tumor's intrinsic vasculature.

METHODS

Comparative analysis of optical coherence tomography angiography findings in consecutive patients diagnosed with choroidal nevus or choroidal melanoma following a complete ophthalmic evaluation, including best-corrected visual acuity and several imaging studies: color fundus photography, B-scan ultrasound, spectral-domain optical coherence tomography, and optical coherence tomography angiography. Optical coherence tomography angiography was used to investigate qualitative differences in the tumor vasculature.

RESULTS

Thirty-six eyes (18 cases of choroidal nevus and 18 cases of choroidal melanoma) from 36 consecutive patients were included in the study. Only cases located posterior to equator were included to enable performance of all tests. On optical coherence tomography angiography, choroidal nevus showed well-delimited margins (78%), hyperreflective choroid capillary vasculature (83%), fewer avascular areas (17%), and neovascular membrane in one case (6%). Choroidal melanoma showed imprecise margins (72%), hyporeflective choroidal capillary vasculature (72%), multiple avascular areas (78%), and choroidal vascular changes (e.g. thick vascular networks or vascular loops; 45%).

CONCLUSION

Optical coherence tomography angiography can provide useful information for assessing and differentiating between choroidal nevi and small melanomas. Significant differences between these conditions were found for the pattern of reflectivity, and presence/absence of avascular zones and vascular anomalies, which could be helpful for supporting the diagnosis.

Use of OCT Angiography in Choroidal Melanocytic Tumors

Objective

To describe OCTA findings in choroidal melanocytic tumors, especially the microcirculation patterns, and to try to correlate with the histopathological studies.

Methods

Cross-sectional, comparative, observational study. 70 cases, including 55 choroidal nevi and 15 choroidal melanomas. Three different observers evaluated specific variables in the choriocapillaris layer on AOCT images and searched for images which described histopathologic vascular patterns, and also, a general description of the images was made. Complementary multi-imaging studies included EDI SD-OCT, color and autofluorescence fundus imaging, Doppler ultrasound, and indocyanine/fluorescein angiography.

Main Results

Good quality studies were acquired in 80% of the cases, with kappa indexes 0.768-0.958. Nevus OCTA images were described mainly as hyperreflective (72.7%), whereas choroidal melanoma as iso/hyporeflective (62.5%). Avascular areas were found in 50.96% and in 33.3% of choroidal nevus and choroidal melanomas, respectively. A neovascular membrane was found only in cases of choroidal nevus (16.3%). Only in cases of choroidal melanomas, we found vascular loops (6.6%) or vascular networks (6.6%).

Conclusion

OCTA is a promising new technology that can be used to study in vivo the differential characteristics of microcirculations between posterior segment melanocytic lesions. Today, larger studies are needed to corroborate these findings and to correlate it with malignancy.

MuSIC report III: tumour microcirculation patterns and development of metastasis in long-term follow-up of melanocytic uveal tumours

PURPOSE

To statistically determine differences in microcirculation patterns between nevi and uveal melanomas and the influence of these patterns on metastatic potential in the long-term follow-up of 112 patients with melanocytic uveal tumours. In vivo markers indicating malignancy and metastatic potential have implications for treatment decision.

METHODS

Primary diagnosis and work-up included clinical examination, fundus photography, standardized A and B scan echography as well as evaluation of tumour microcirculation patterns via confocal fluorescein and indocyanine green angiography (ICGA). Patient data were collected from the patient files, the tumour registry or personal contact. Statistical analysis was performed with spss 22.0 using chi-square, Fisher's exact test and Kaplan-Meier survival analysis.

RESULTS

Forty-three uveal melanocytic lesions remained untreated and were retrospectively classified as benign nevi, whereas 69 lesions were malignant melanomas (T1: 32, T2: 28, T3: 6 and T4: 3). 'Silent' and 'arcs without branching' were found significantly more often in nevi (p = 0.001 and p = 0.010), whereas 'parallel with cross-linking' and 'networks' were significantly more frequent in melanomas (p = 0.022 and p = 0.029). The microcirculation pattern 'parallel with cross-linking' proved significantly more frequent in patients who developed metastases (p = 0.001).

CONCLUSIONS

Certain microcirculation patterns may guide us in differentiating uveal nevi from malignant melanomas. A non-invasive prognostic marker can be of great value for borderline lesions in which cytology is less likely taken. 'Parallel with cross-linking' did not only indicate malignancy, but it was also associated with later tumour metastasis.

Swept-source optical coherence tomography features of choroidal nevi

PURPOSE

To investigate the morphologic characteristics of choroidal nevi using swept-source optical coherence tomography and compare this with enhanced-depth optical coherence tomography.

DESIGN

Retrospective observational case series.

METHODS

One choroidal nevus each from 30 eyes of 30 patients was included and received imaging with swept-source OCT (SS-OCT) and enhanced-depth imaging OCT (EDI-OCT). For SS-OCT, a scan acquisition protocol was used involving 12 mm horizontal and vertical scans in the posterior fundus. The main outcome measures were morphologic features of choroidal nevi obtained with SS-OCT imaging. These features were compared to images obtained with EDI-OCT. A 2-tailed Fisher exact test was the statistical method used.

RESULTS

SS-OCT allowed for an appreciation of intralesional details: Of the 30 nevi imaged, intralesional vessels were apparent in 30 (100%), intralesional cavities in 6 (20%), intralesional granularity in 14 (47%), abnormal choriocapillaris in 25 (83%), and abnormal choriocapillaris confined to the tumor apex in 17 (58%). Distended bordering vessels were identified in 22 nevi (73%) and were significantly associated with the presence of previous or persistent subretinal fluid. Intrinsic hyperreflectivity with hyporeflective shadowing was significantly (P = .05) more apparent in 14 of 21 melanotic nevi (67%) compared with 2 of 9 amelanotic nevi (22%). Visualization of the complete nevus-scleral interface was significantly (P = .02) more apparent in 7 of 9 amelanotic nevi (78%) compared with 6 of 21 melanotic nevi (29%), and was not significantly related to tumor thickness (measured by ultrasound) or to tumor configuration. Tumor diameter (but not tumor height) was statistically significantly associated with secondary retinal changes (P = .05) and configuration (P = .01). EDI-OCT was equivalent at determining secondary retinal changes (P = .29), the presence of distended bordering vessels (P = 1), visualization of the nevus-scleral interface (P = .6), and hyporeflective gradation at the nevus-scleral interface (P = .33). However, in melanotic lesions, SS-OCT was significantly superior at visualizing intralesional vessels (P = .0002), intralesional granularity (P = .0005), and abnormal choriocapillaris (P = .0001).

CONCLUSION

Imaging of choroidal nevi with SS-OCT enables visualization of intralesional details such as vessels (present in 100% of tumors imaged), cavities, and granularity. For melanotic lesions, SS-OCT is significantly better at depicting certain intralesional characteristics compared to EDI-OCT. Distended bordering vessels were recognized in over two thirds of the nevi imaged and were significantly associated with previous or persistent subretinal fluid.

Clinical, pathologic, and imaging features and biological markers of uveal melanoma

Uveal melanoma has unique clinical and pathologic features including virtually exclusive metastasis to the liver in high-risk cases. In this chapter, the clinical findings in uveal melanoma and diagnostic methods including imaging tests and serum markers are described. Additionally, the histopathologic features including the modified Callender classification and immunohistochemical findings of uveal melanoma are described.

Why is melanoma so metastatic?

Malignant melanoma is one of the most aggressive cancers and can disseminate from a relatively small primary tumor and metastasize to multiple sites, including the lung, liver, brain, bone, and lymph nodes. Elucidating the molecular and genetic changes that take place during the metastatic process has led to a better understanding of why melanoma is so metastatic. Herein, we describe the unique features that distinguish melanoma from other solid tumors and contribute to the malignant phenotype of melanoma cells. For example, although melanoma cells are highly antigenic, they are extremely efficient at evading host immune response. Melanoma cells share numerous cell surface molecules with vascular cells, are highly angiogenic, are mesenchymal in nature, and possess a higher degree of 'stemness' than do other solid tumors. Finally, analysis of melanoma mutations has revealed that the gene expression profile of malignant melanoma is different from that of other cancers. Elucidating these molecular and genetic processes in highly metastatic melanoma can lead to the development of improved treatment and individualized therapy options.

Expression of vascular endothelial growth factor a, matrix metalloproteinase 9 and extravascular matrix patterns in iris and ciliary body melanomas

PURPOSE

It was the aim of this study to assess the expression of vascular endothelial growth factor (VEGF)-A, matrix metalloproteinase (MMP)-9 and extravascular matrix patterns (EMPs) in iris and ciliary body melanomas and their correlations with histopathologic parameters.

METHODS

The study was conducted on 3 iris and 15 ciliary body melanomas. All tumors were subjected to immunohistochemical techniques for VEGF-A and MMP-9 expressions, the presence of EMPs was assessed, and routine paraffin sections were stained with hematoxylin-eosin. Cell type, tumor localization, degree of pigmentation, necrosis, mitotic index, lymphocytic infiltration and sclera invasion were analyzed using light microscopy.

RESULTS

The mean patient age at the time of treatment was 43 years (range 19-69, median 39.5); 10 (55.6%) patients were males and 8 (44.4%) females. Histopathological cell types were spindle cells in 55.6%, mixed cells in 16.7%, and epithelioid cell types in 27.8% of tumors. Positive reaction for VEGF-A and MMP-9 was present in 66.7 and 72.3% of the tumors, respectively. Microvascular loops and/or networks were seen in 33.4% of the tumors, with the remaining 66.7% of tumors displaying one or more of the other patterns. Metastatic disease developed in only 1 patient during follow-up. Tumor cell type, tumor size, mitotic rate, degree of pigmentation and EMPs were not correlated with metastasis.

CONCLUSIONS

This study suggests that VEGF-A and MMP-9 were positive in the majority of iris and ciliary body melanomas. No correlation was found between VEGF-A and MMP-9 immunoreactivity and EMPs and occurrence of metastases in cases of anterior uveal melanoma.

A gene transfer comparative study of HSA-conjugated antiangiogenic factors in a transgenic mouse model of metastatic ocular cancer

Different antiangiogenic and antimetastatic recombinant adenoviruses were tested in a transgenic mouse model of metastatic ocular cancer (TRP1/SV40 Tag transgenic mice), which is a highly aggressive tumor, developed from the pigmented epithelium of the retina. These vectors, encoding amino-terminal fragments of urokinase plasminogen activator (ATF), angiostatin Kringles (K1-3), endostatin (ES) and canstatin (Can) coupled to human serum albumin (HSA) were injected to assess their metastatic and antiangiogenic activities in our model. Compared to AdCO1 control group, AdATF-HSA did not significantly reduce metastatic growth. In contrast, mice treated with AdK1-3-HSA, AdES-HSA and AdCan-HSA displayed significantly smaller metastases (1.19+/-1.19, 0.87+/-1.5, 0.43+/-0.56 vs controls 4.04+/-5.12 mm3). Moreover, a stronger inhibition of metastatic growth was obtained with AdCan-HSA than with AdK1-3-HSA (P=0.04). Median survival was improved by 4 weeks. A close correlation was observed between the effects of these viruses on metastatic growth and their capacity to inhibit tumor angiogenesis. Our study indicates that systemic antiangiogenic factors production by recombinant adenoviruses, particularly Can, might represent an effective way of delaying metastatic growth via inhibition of angiogenesis.

Selected pigmented fundus lesions of children

BACKGROUND

Ocular cells that accumulate melanin pigment are derived from 1 of 2 sources, the optic vesicle or the neural crest. Migration and distribution of pigment containing cells may go awry during fetal development or these cells may be altered before or after birth either by local or systemic stimuli. Specific recognition patterns of pigment distribution often exist and may relate directly to a single disease process.

METHODS

Records of pediatric patients with disorders of pigment distribution in the ocular fundi who had been examined by the author were reviewed.

RESULTS

Five disorders with recognizable patterns of retinal pigment epithelium (optic vesicle derivation) disturbance (congenital hypertrophy of the retinal pigment epithelium, Gardner syndrome, chronic granulomatous disease, preserved para-arteriole retinal pigment epithelium in (autosomal-recessive) retinitis pigmentosa, and combined hamartoma of the retina and retinal pigment epithelium), and 5 disorders of cells originating from the neural crest (choroidal nevi, choroidal melanoma, melanocytoma, ocular melanosis, and oculodermal melanosis), were selected for illustration and discussion.

CONCLUSIONS

These arbitrarily selected groups of disorders affect or involve patterns of pigment deposition in the ocular fundus. These patterns are recognizable and distinguishable one from another but have different implications for treatment and follow-up. Progress in recognizing distinguishing characteristics, diagnostic implications, understanding, and treatment of these disorders during the past 40 years is compared and contrasted between the 2 groups.

Morphology of angiogenesis in human cancer: a conceptual overview, histoprognostic perspective and significance of neoangiogenesis

This paper reviews the histomorphological aspects of angiogenesis and neoangiogenesis, quantitative and qualitative, and their applications in prognostic evaluation of neoplastic diseases. The merits and weak points of intratumoral microvessel density (MVD), a widely regarded bona fide predictor of tumour growth, metastases and patient survival, are discussed. Total microvascular area (TVA) has been found useful in recent prognostic studies utilizing newer immunohistochemical vascular markers. Of particular significance is the fact that MVD and TVA are most predictive of patient outcome in those tumours that induce significant neoangiogenesis, namely carcinomas of breast and prostate, and haematological malignancies. In contrast, carcinomas of lung and urinary bladder do not show significant associations of MVD and TVA with poor prognosis, reflecting differences in angiogenic mechanisms. In gliomas, MVD appears to correlate with outcome in high-grade, but not low-grade tumours, and does not correlate with tumour cellularity in the infiltrating portions of the tumour, reflecting a paucity of neoangiogenesis and directional vascular growth. Recent studies have found CD105, Tie-2/Tek and vascular endothelial growth factor receptors to be the best markers of neoangiogenesis. The vascular parameters so measured correlate better with overall and disease-free survival in breast, colon and lung carcinoma than panendothelial markers such as CD31. A correlation of vascular patterns with prognosis has been established in ocular melanomas, glioblastomas and squamous carcinomas of head and neck region. Vascular networks with closed loops are closely associated with mortality due to metastases in uveal melanomas. Fewer bizarre glomeruloid vessels and prominent classical capillary pattern was an independent predictor of longer survival in glioblastoma. Therefore a judicious combination of quantitative and qualitative microscopic angiogenic parameters, with emphasis on neoangiogenesis and vascular patterns wherever applicable, should be an integral component of a more consistent tumour staging system for accurate prognostic evaluation of tumours, selection of optimal anti-angiogenic therapy and pertinent research.

Vasculogenic mimicry

The term vasculogenic mimicry describes the formation of fluid-conducting channels by highly invasive and genetically dysregulated tumor cells. Two distinctive types of vasculogenic mimicry have been described. Vasculogenic mimicry of the tubular type may be confused morphologically with endothelial cell-lined blood vessels. Vasculogenic mimicry of the patterned matrix type in no way resembles blood vessels morphologically or topologically. Matrix proteins such as laminin, heparan sulfate proteoglycan, and collagens IV and VI have been identified in these patterns. The patterned matrix anastomoses with blood vessels, and systemically injected tracers co-localize to these patterns. Vasculogenic mimicry of the patterned matrix type has been identified in uveal, cutaneous and mucous membrane melanomas, inflammatory and ductal breast carcinoma, ovarian and prostatic carcinoma, and soft tissue sarcomas, including synovial sarcoma rhabdomyosarcoma, osteosarcoma, and pheochromocytoma. Because the microcirculation of many tumors may be heterogeneous -- including incorporated or co-opted vessels, angiogenic vessels, mosaic vessels, and vasculogenic mimicry of the tubular and patterned matrix types -- therapeutic regimens that target angiogenesis alone may be ineffective against highly invasive tumors that contain patterned matrices. Vasculogenic mimicry provides an opportunity to investigate the interrelationships between the genetically dysregulated invasive tumor cell, the microenvironment, and the malignant switch.

Microvascular loops and networks in uveal melanoma

Microvascular patterns--three-dimensional architectural arrangements of microvessels and extravascular matrix in uveal melanoma--were discovered when investigators were looking for histopathological features of sufficient size to be imaged clinically. Evidence that these patterns may be formed by tumour cells and that they may be able to conduct plasma and blood as well as discovery of similar elements in other cancers make them of general importance. Of nine different patterns described, closed microvascular loops and networks have been studied most extensively. When cell type, microvascular density and nucleolar size are controlled for, these two patterns independently predict time to metastasis. In addition to visualization in tumour specimens stained with periodic acid-Schiff reagent, they can often be visualized clinically on confocal indocyanine green angiography. The presence of networks is clinically associated with probability of growth of small uveal melanocytic tumours and with the rate of regression of uveal melanoma after brachytherapy. Networks are also associated with development of exudative retinal detachment from uveal melanoma. Histopathological studies show that loops and networks are less common in tumours enucleated after irradiation and that they are frequently repeated in metastases of uveal melanoma. Avenues for immediate future research include detailed elucidation of the histogenesis of microvascular patterns and determination of these patterns in metastatic melanoma to identify new histopathological characteristics for prognostication when clinical metastases have developed.

Anterior segment tumors: current concepts and innovations

The most common anterior segment tumors are primary neuroepithelial cysts, uveal melanomas, metastatic tumors, and benign tumors. In the majority of cases, the diagnosis can be made utilizing a careful clinical history and ocular examination. Ultrasound examination (low and high frequency) has become an indispensable tool used to determine tumor extension and involvement of the surrounding structures. In particular, high-frequency ultrasound has been used to uncover iris pigment epithelial cysts, to allow for the diagnosis of small ciliary body melanomas, and to measure tumors for plaque radiation planning. Whereas fluorescein angiography and computerized tomography have come to play a limited role, fine-needle aspiration biopsy has been found to be quite helpful in selected cases. Once the diagnosis is established, treatment decisions depend on the tumors' location, size, local extension, patterns of growth, and secondary complications. Most anterior segment tumors can be observed for growth prior to treatment. Other options include local resection (iridectomy, lamellar sclerouvectomy, or eye-wall resection) and radiation (ophthalmic plaque or external beam). Enucleation is typically employed if these eye- and vision-sparing treatments are not possible and for uncontrollable secondary glaucoma. This review examines the unique role of high-frequency ultrasonography for the diagnosis and treatment of anterior segment tumors as well as an overview of clinical practice.

Complex microcirculation patterns detected by confocal indocyanine green angiography predict time to growth of small choroidal melanocytic tumors: MuSIC Report II

PURPOSE

Multiple independent laboratories have confirmed the histologic observation that some tumor microcirculation patterns (MCPs) in uveal melanomas are associated strongly with death resulting from metastatic disease. Because these patterns are imageable with confocal indocyanine green angiography (ICG), we designed a prospective study to evaluate whether these angiographically detectable MCPs predict time to tumor growth.

DESIGN

Observational case series, prospective, non-randomized.

PARTICIPANTS

Ninety-eight patients with unilateral, small, choroidal melanocytic tumors.

METHODS

The following information and tumor characteristics were recorded for each patient: demographic parameters, best-corrected visual acuity, intraocular pressure, related visual symptoms, location and dimension of tumor, pigmentation, orange pigment, drusen, tumor-associated hemorrhage, subretinal fluid, and confocal ICG angiographically determined microcirculation patterns-silent (avascularity), normal (preexisting normal choroidal vessels within the tumor), straight vessels, parallel without and with cross-linking, arcs without and with branching, loops, and networks.

MAIN OUTCOME MEASURES

Time to growth of the tumor, with growth defined as an increase in the maximal apical tumor height of 0.5 mm measured by standardized A-scan ultrasonography, photographic documentation of an increase of the largest basal diameter of at least 1.5 mm, advancement of one tumor border of at least 0.75 mm, or a combination thereof.

RESULTS

Twenty-eight of the 98 tumors in this study (29%) met the predetermined criteria for tumor growth. The median time to growth was 127 days (range, 51-625 days). The following tumor characteristics were significantly associated with time to tumor growth: flashes (P = 0.0224), orange pigment (P = 0.012), subretinal fluid (P < 0.001), maximum basal tumor diameter at initial examination (P = 0.015), maximum apical tumor height (P < 0.001), parallel with cross-linking MCP (P < 0.001), arcs with branching MCP (P = 0.006), loops (P < 0.001), and networks (P < 0.001). Of these, the angiographic documentation of any of the complex MCPs (parallel with cross-linking, arcs with branching, loops, networks, or a combination thereof) showed the strongest association with the time to tumor growth in a Cox proportional hazard model.

CONCLUSIONS

The characteristics of our patient cohort are comparable by clinical and echographic parameters with cohorts for predicting tumor growth, described previously in the literature. In addition, we detected a novel clinical predictor of tumor growth: the confocal ICG angiographic detection of complex MCPs.

An orthotopic model for human uveal melanoma in SCID mice

The microcirculation of primary uveal melanomas, their precursors, and their metastases is distinctive. Medium-sized and even large primary uveal melanomas typically lack significant zones of necrosis, suggesting that either these tumors are relatively well perfused or they are capable of growth in a severely blood-deprived microenvironment. In addition to normal choroidal vessels that are incorporated into nevi and most primary uveal melanomas, aggressive primary and metastatic uveal melanomas tend to contain patterns of extracellular matrix that surround spheroidal or cylindrical packets of tumor cells. Some components of this branching, looping, and interconnected system of matrix may be perfused. It is now known that the generation of this patterning is a characteristic of genetically dysregulated melanoma cells (nonaggressive tumor cells do not form these patterns and melanomas lacking branching, looping, or interconnected matrix patterns tend to follow a relatively indolent course). We developed an orthotopic model of an aggressive human uveal melanoma by injecting suspensions of the primary human choroidal melanoma cell line (OCM1) into the subretinal space of one eye of 20 SCID mice. All mice were examined daily for tumor growth and tumors developed in every eye within 3 weeks of injection. The tumors were characterized by extraocular extension and the development of looping matrix patterns characteristic of those seen in aggressive human uveal melanoma. As in human uveal melanomas, these patterns were perfused by blood in areas. The orthotopic injection of human uveal melanoma cells into the SCID mouse eye generates a model reproducing the matrix-associated microcirculatory patterns of aggressive primary human uveal melanomas. This model can be used to explore the molecular pathogenesis and modulation of this novel circulation in vivo, to facilitate our understanding of the blood flow to these tumors providing insight into perfusion and drug delivery, to enable testing of pharmacologic modulation of pattern formation and intratumoral blood flow, and to refine noninvasive methods such as confocal scanning laser ophthalmoscopy to detect the presence of these patterns by which ophthalmologists might assess the biological behavior of tumors as noninvasive substitute for biopsy.

Control of melanoma morphogenesis, endothelial survival, and perfusion by extracellular matrix

The morphogenetic properties of endothelial cells and melanoma cells were tested under varying matrix quantities and distributions and under constant and saturating levels of growth factors. Aggressive melanoma cells self-assembled into cords vasculogenically only when seeded on thin matrices: nonaggressive melanoma cells did not mimic endothelial cell behavior under any matrix thickness. When buried in matrix, however, aggressive melanoma cells generated looping patterns that contained tumor cells and matrix. These patterns were different topologically and compositionally from cord-like structures or blood vessels but were nevertheless capable of conducting dye by microinjection or passive diffusion. When seeded on three-dimensional cultures of nonaggressive nonpattern-forming melanoma cells, prelabeled endothelial cells attached to, penetrated through, and survived for 2 weeks but failed to form vasculogenic cords. In cocultures containing aggressive melanoma cells, endothelial cells survived briefly but formed short cords only in contact with looping patterns formed by the aggressive tumor cells. Time-lapse recording showed that endothelial cells were lysed upon direct contact with aggressive melanoma cells. Looping patterns identified in human tissue samples were composed ultrastructurally of electron-dense material on either side of a layer of tumor cells; scattered red blood cells were seen in this central cellular layer. By immunohistochemistry, patterns labeled with laminin and fibrinogen colocalized to these looping laminin-positive patterns, suggesting the presence of plasma within these patterns from contiguous leaky tumor vessels. These observations are consistent with the perfusion of these patterns in vitro and with repeated demonstrations of the colocalization of intravenous tracers to looping laminin patterns in animal xenograft models by independent groups. Thus, the distribution and localized quantity of extracellular matrix in aggressive melanomas contributes to the regulation of tumor cell morphogenesis, modulates interactions between tumor cells and endothelial cells, and may contribute to an extravascular matrix-directed circulation.

Imaging the microcirculation of untreated and treated human choroidal melanomas

INTRODUCTION

Histologically demonstrable microcirculation patterns (microcirculation pattern) of human choroidal melanomas have prognostic significance for the patient. We report on our experience in imaging these microcirculation pattern in vivo using simultaneous confocal Fluorescein (FA)- and Indocyaninegreen (ICG) angiography before and after brachytherapy.

PATIENTS AND METHODS

The simultaneously procured confocal FA- and ICG angiograms of 50 patients with untreated choroidal melanomas were studied for the visibility of microcirculation pattern. Patients were also followed with simultaneous FA/ICG after brachytherapy.

RESULTS

Confocal FA disclosed signs of tumor vascularization in 12 (24%) of the 50 examined patients but microcirculation pattern only in 3 patients (6%). In contrast, simultaneously obtained confocal ICG disclosed microcirculation pattern in 47 patients (94%). In 10 (77%) of the 13 patients the tumor microcirculation changed considerably after brachytherapy: Distortion, thickening, thinning, as well as complete obliteration of vessels could be observed.

CONCLUSION

Histologically demonstrated microcirculation pattern can be imaged in vivo. This offers the possibility to assess the likely biologic behavior of the individual tumor without the need for obtaining a cytologic or histologic specimen via enucleation or fine-needle biopsy. Confocal ICG angiogiography images microcirculation pattern better than FA which can be explained by the different absorption-, fluorescence- and exudation-characteristics ICG. Follow-up with confocal ICG of choroidal melanomas after brachytherapy shows different features and allows for visualization of the microcirculation reaction to the treatment which might be a useful tool for studying the effects of future anti-angiogenesis based tumor therapies.

Melanoma-stroma interactions: structural and functional aspects

Cutaneous melanomas are notorious for their tendency to metastasise. Because the tumour microenvironment plays an important part in tumour development and progression, we review the structural and functional aspects of interactions between melanoma and the stroma. We emphasise fibrovascular patterns (both in uveal and cutaneous melanoma), cellular and extracellular composition of the stroma, and the molecules involved. Also, we discuss functional interactions, focusing on melanoma-fibroblast cross-talk by soluble factors and by direct cell-cell contact. On the basis of recent findings we propose that involvement of fibroblasts in melanoma-stromagenesis occurs through different stages: recruitment, activation, and conversion to myofibroblasts, or differentiation to fibrocytes. We reason that this involvement is topographically linked to different areas in and around the tumour, and hypothesise that stromal activation, as seen in tumor ulceration or immunological regression in melanoma, stimulates tumour progression.

Mapping the Location of Prognostically Significant Microcirculatory Patterns in Ciliary Body and Choroidal Melanomas

The microcirculation of choroidal and ciliary body melanomas is remodeled into architecturally distinctive patterns. The presence of two histologic microvascular patterns, networks and parallel vessels with cross-linking, is strongly associated with metastasis. This study was designed to test the hypothesis that networks and parallel vessels with cross-linking patterns are not distributed evenly throughout the tumor. From a set of 234 eyes removed for ciliary body or choroidal melanoma, 152 tumors contained at least one focus of either vascular networks or parallel vessels with cross-linking. Histological cross-sections were digitized and foci of tumor containing these patterns were pseudocolorized so that their location within the periphery or central tumor zone could be mapped. Ciliary body and choroidal melanomas vary widely in size and shape and it is not appropriate to describe the periphery of a tumor as a fixed value because in a small tumor, the periphery thus defined would occupy a larger percent area than in a larger tumor. In this study, the peripheral and central zones of each tumor were described by a function that was constant from tumor to tumor, allowing the width of the peripheral and central zones to vary proportionally with tumor size. Observed counts of vascular patterns per zone were compared statistically with expected counts based upon the percent area occupied by the peripheral and central zones. Discrete foci of networks and parallel with cross-linking vessels are over-represented in the tumor periphery (p < 0.0001).

Vasculogenic mimicry and tumor angiogenesis

Tumors require a blood supply for growth and hematogenous dissemination. Much attention has been focused on the role of angiogenesis-the recruitment of new vessels into a tumor from pre-existing vessels. However, angiogenesis may not be the only mechanism by which tumors acquire a microcirculation. Highly aggressive and metastatic melanoma cells are capable of forming highly patterned vascular channels in vitro that are composed of a basement membrane that stains positive with the periodic acid-Schiff (PAS) reagent in the absence of endothelial cells and fibroblasts. These channels formed in vitro are identical morphologically to PAS-positive channels in histological preparations from highly aggressive primary uveal melanomas, in the vertical growth phase of cutaneous melanomas, and in metastatic uveal and cutaneous melanoma. The generation of microvascular channels by genetically deregulated, aggressive tumor cells was termed "vasculogenic mimicry" to emphasize their de novo generation without participation by endothelial cells and independent of angiogenesis. Techniques designed to identify the tumor microcirculation by the staining of endothelial cells may not be applicable to tumors that express vasculogenic mimicry. Although it is not known if therapeutic strategies targeting endothelial cells will be effective in tumors whose blood supply is formed by tumor cells in the absence of angiogenesis, the biomechanical and molecular events that regulate vasculogenic mimicry provide opportunities for the development of novel forms of tumor-targeted treatments. The unique patterning characteristic of vasculogenic mimicry provides an opportunity to design noninvasive imaging techniques to detect highly aggressive neoplasms and their metastases.

Vascular channel formation by human melanoma cells in vivo and in vitro: vasculogenic mimicry

Tissue sections from aggressive human intraocular (uveal) and metastatic cutaneous melanomas generally lack evidence of significant necrosis and contain patterned networks of interconnected loops of extracellular matrix. The matrix that forms these loops or networks may be solid or hollow. Red blood cells have been detected within the hollow channel components of this patterned matrix histologically, and these vascular channel networks have been detected in human tumors angiographically. Endothelial cells were not identified within these matrix-embedded channels by light microscopy, by transmission electron microscopy, or by using an immunohistochemical panel of endothelial cell markers (Factor VIII-related antigen, Ulex, CD31, CD34, and KDR[Flk-1]). Highly invasive primary and metastatic human melanoma cells formed patterned solid and hollow matrix channels (seen in tissue sections of aggressive primary and metastatic human melanomas) in three-dimensional cultures containing Matrigel or dilute Type I collagen, without endothelial cells or fibroblasts. These tumor cell-generated patterned channels conducted dye, highlighting looping patterns visualized angiographically in human tumors. Neither normal melanocytes nor poorly invasive melanoma cells generated these patterned channels in vitro under identical culture conditions, even after the addition of conditioned medium from metastatic pattern-forming melanoma cells, soluble growth factors, or regimes of hypoxia. Highly invasive and metastatic human melanoma cells, but not poorly invasive melanoma cells, contracted and remodeled floating hydrated gels, providing a biomechanical explanation for the generation of microvessels in vitro. cDNA microarray analysis of highly invasive versus poorly invasive melanoma tumor cells confirmed a genetic reversion to a pluripotent embryonic-like genotype in the highly aggressive melanoma cells. These observations strongly suggest that aggressive melanoma cells may generate vascular channels that facilitate tumor perfusion independent of tumor angiogenesis.

Evaluation of the human choroidal melanoma rabbit model for studying microcirculation patterns with confocal ICG and histology

The aim of this study was to develop consistently focal elevated choroidal masses of human choroidal melanoma in immunosuppressed rabbits and to correlate the visualization of prognostically significant microcirculation patterns from confocal indocyanine green angiography with histologic microcirculation patterns. A human choroidal melanoma cell line (OCM1) was implanted in the choroid of 40 rabbit eyes using three different techniques: transscleral choroidal injection of a cell suspension, injection of a cell suspension in a surgically induced cyclodialysis cleft, and implantation of solid tumor fragments in a surgically induced cyclodialysis cleft. The rabbits were immunosuppressed with daily injections of Cyclosporin A to prevent host versus graft reaction. The eyes were studied weekly with indirect ophthalmoscopy and fundus photography to monitor tumor growth and indocyanine green angiography using a confocal scanning laser ophthalmoscope to identify microcirculation patterns in vivo and correlate these findings with the histologic demonstration of tumor microcirculation patterns. A tumor mass was identified by indirect ophthalmoscopy in 16 of the 40 implanted rabbit eyes (40%). Each of these tumors was confirmed histologically to represent a focal elevated choroidal mass. All 16 elevated choroidal masses grow in eyes in which solid tumor fragments were implanted. In total, a melanoma was identified histologically in 28 of the implanted 40 eyes (70%). In addition to the 16 eyes where the melanoma appeared as a focal elevated choroidal mass, 4 eyes contained a focal elevated mass in the sclera and 8 eyes contained a flat choroidal tumor. Histologically, microcirculation patterns were identified only in the 16 eyes with focal elevated choroidal masses. Confocal indocyanine green angiography imaged microcirculation patterns in 13 of these 16 eyes (81%). The surgical implantation of small solid fragments of human choroidal melanoma in immunosuppressed rabbit eyes provides the best method to consistently obtain focal elevated choroidal masses. These focal elevated choroidal masses resemble booth the localization and the growth pattern of choroidal melanomas in humans. In addition, they also contain microcirculation patterns similar to those seen in humans that are detectable with confocal indocyanine green angiography. The use of indocyanine green angiography with this animal model may be especially useful in designing and evaluating anti-microcirculation treatments directed at uveal melanoma.

Microvascular loops and networks as prognostic indicators in choroidal and ciliary body melanomas

BACKGROUND

Malignant melanoma of the ciliary body and choroid of the eye is a tumor that disseminates frequently, and 50% of the diagnosed patients die within 10 years. We investigated the hypothesis that, by histopathologic analysis of the arrangement of microvessels (i.e., small blood vessels) in loops and networks, we might be able to differentiate better those patients with a favorable prognosis from those with a poor prognosis.

METHODS

We conducted a population-based, retrospective cohort study of melanoma-specific and all-cause mortality for 167 consecutive patients who had an eye surgically removed because of malignant choroidal or ciliary body melanoma during the period from 1972 through 1981. Microvascular loops and networks were evaluated independently by two pathologists who were unaware of patient outcome.

RESULTS

Microvascular patterns could be assessed in 134 (80%) of 167 melanoma specimens. The 10-year probability of melanoma-specific survival was worse if microvascular loops (0.45 versus 0.83; two-sided P<.0001) and networks (0.41 versus 0.72, two-sided P<.0001) were present. In multivariate Cox regression analysis of melanoma-specific survival, the hazard ratios were 1.66 (95% confidence interval [CI] = 1.19-2.30) for the presence of loops and networks as a combined three-category variable, 2.36 (95% CI = 1.37-4.05) for the presence of epithelioid cells, 1.11 (95% CI = 1.03-1.19) for the largest basal tumor diameter (evaluated as a continuous variable), and 2.14 (95% CI = 1.25-3.67) for ciliary body involvement.

CONCLUSIONS

Patients with malignant uveal melanoma who have a favorable prognosis can be distinguished from those with a poor prognosis by histopathologic analysis of microvascular patterns in uveal melanoma tumor specimens.

Ultrastructural and immunohistochemical studies of the periendothelial matrix in human melanoma: evidence for an amorphous matrix containing laminin

Angiogenesis and the extracellular matrix are fundamental to tumor progression from in situ to invasive and metastatic disease. Laminin, a major glycoprotein integrated into basement membranes, is observed in angiogenesis and tumorigenesis. A recent study described an association between melanoma cells and endothelial cells via an amorphous matrix containing laminin. In the current study, we have examined 45 cases of human primary and metastatic melanomas by electron microscopy for the presence of an amorphous matrix. We observed an amorphous matrix without a clearly delineated lamina or basement membrane in 41 of the 45 melanomas studied. 28 cases with tissue blocks available for study were examined by immunohistochemistry for the expression of laminin and type IV collagen. We observed the presence of an angiocentric matrix containing laminin in 24 of the 28 melanomas studied. Since laminin is involved in tumor migration, the presence of laminin between melanoma cells and small vessels suggests a role for this material in periendothelial tumor migration. However, further study is required to characterize the nature of this material and the mechanisms involved.

Microcirculation architecture of metastases from primary ciliary body and choroidal melanomas

PURPOSE

To describe the microcirculation architecture of metastatic choroidal and ciliary body melanoma.

METHOD

Histologic sections of 35 metastases from 19 primary melanomas were stained to demonstrate microcirculation.

RESULT

The appearance of microcirculatory networks in metastases is independent of the target organ but associated with the size of the metastatic deposit (estimated coefficient = 0.5959; SE = 0.3024; P = .0488).

CONCLUSION

The microcirculatory patterns of primary uveal melanomas that are associated with metastatic behavior appear in foci of metastasis, regardless of the site of dissemination.

Ultrasonic mapping of the microvasculature: signal alignment

The ultimate goal of this work was the development of a system capable of estimating the low flow velocities in the microvasculature. Estimation of low velocity flow within these vessels is challenging due to the small signal levels and the effect of cardiac and respiratory motion. Realignment of the signal from a single line-of-sight to remove physiological tissue motion is a critical part of the process of small-vessel flow mapping, and our methods for this alignment are considered in this paper. Each method involves the correlation of pulses acquired from the same line-of-sight. The first method involves the correlation of adjacent pulses (nearest-neighbor), the second involves a single reference line and the third involves averaging the correlation over a set of reference lines. We find that a nearest-neighbor strategy is suboptimal, and that strategies involving a global reference line are superior. A bound on the variance of estimates of the location of the correlation peak is presented. This bound allows us to consider our results in comparison with an absolute limit. Finally, a new algorithm allowing for alignment between lines-of-sight is described, and initial results are presented. Such an algorithm does, in fact, reduce jitter, correct for tissue motion and enables us to better visualize vessel continuity. We find that vessels as small as 40 microm can be mapped in two dimensions using a 50-MHz transducer.

Ocular melanomas and melanocytic lesions of the eye

This article describes several melanocytic lesions of the eye. Benign and malignant lesions will be discussed as well as a review of the dysplastic nevus syndrome and its proposed association with ocular melanoma. Ocular melanomas arise from the same embryologically derived melanocytes as their cutaneous counterparts. However, ocular and cutaneous melanomas differ in many respects. The diagnosis and management of these ocular tumors rely heavily on the ophthalmologist. However, knowledge of melanocytic lesions will aid the dermatologist in detection and in proper referral of these patients.

Fluorescent infrared scanning-laser ophthalmoscope for three-dimensional visualization: automatic random-eye-motion correction and deconvolution

Scanning-laser ophthalmoscope (SLO) technology has provided, among other possibilities, the potential for three-dimensional (3-D) visualization of anatomy in the posterior pole of the eye. The use of indocyanine green (ICG) as an infrared fluorescent marker of vasculature in combination with aninfrared SLO (the Heidelberg Retina Angiograph) is presented. Presently, two main factors among others discussed impede the visualization of 3-D structures in observed SLO data. Random eye motion between optical sections and (to a lesser degree) motion between raster scan lines prevent assessment of spatial orientation and connectivity of vasculature. Second, smear along the optic axis owing to the optics prevents accurate determination of vessel or lesion size and shape, especially for features spanning several optical sections. A novel, to our knowledge, deconvolution algorithm is described that automatically corrects for the poor axial (optical-sectioning) resolution of the SLO and for patient random eye motion during target fixation. Encouraging preliminary results are presented showing the usefulness of applying blind deconvolution toward improving the 3-D clarity of SLO data. Although clinical and medical research applications are broad, the specific medical sample selected shows the potential of examining microvascular 3-D morphology for diagnosis and treatment of choroidal tumors.

The microcirculation of choroidal and ciliary body melanomas

The microcirculation of ciliary body and choroidal melanomas is remodelled into patterns. The presence of microvascular networks, composed of back-to-back loops that encircle microdomains of tumour, and parallel vessels with cross-linking, are associated with death from metastatic melanoma. The formation of these complex vascular patterns may result from reciprocal interactions between the tumour cell and the extracellular matrix, and pattern formation may reflect an invasive tumour cell phenotype. Ciliary body and choroidal melanomas are among the few forms of cancer treated before a pathologist assigns a grade to indicate whether tumour is likely to follow a benign or aggressive course. There is evidence to suggest that prognostically significant microcirculatory patterns may be detectable by non-invasive imaging techniques that may provide a substitute for biopsy to guide the clinical management of patients with these sight- and life-threatening tumours.

Relative importance of quantifying area and vascular patterns in uveal melanomas

PURPOSE

To test whether the cross-sectional area of choroidal and ciliary body melanomas and quantification of microcirculatory networks and parallel vessels with cross-linking are features associated with death from metastatic melanoma, and to compare new with conventional histologic prognostic features.

METHODS

The cross-sectional area of 234 ciliary body or choroidal melanomas was measured from digitized images of histologic sections. The percentage of cross-sectional area occupied by two microcirculatory patterns-networks and parallel vessels with cross-linking-was calculated for the 152 tumors containing at least one focus of either pattern. Kaplan-Meier survival curves were generated based on cross-sectional and percentage of cross-sectional areas of these patterns. Cox proportional hazard regression methods related time to death from melanoma with sets of predictor variables. For each model, percent variation explained was computed.

RESULTS

Patient survival differs significantly when tumors are classified based on cross-sectional area: small (<16 mm2), medium (> or =16 mm2 but <61.4 mm2), and large (> or =61.4 mm2). Patients with tumors containing networks and parallel vessels with cross-linking microcirculation patterns that occupy 2% of cross-sectional area have a significantly worse prognosis than do those patients with tumors containing a smaller percentage of these patterns.

CONCLUSIONS

Quantifying cross-sectional tumor area and the percentage area occupied by networks and parallel vessels with cross-linking microcirculatory patterns in ciliary body and cho. roidal melanomas provides significant prognostic information. Compared with more conventional prognostic characteristics, the most dramatic increase in prognostic information is provided by determination of the presence or absence of microvascular patterns.

Reassessment of the PAS patterns in uveal melanoma

BACKGROUND

Previous work has highlighted the prognostic importance of patterns of periodic acid Schiff (PAS) staining (the Folberg patterns) in uveal melanoma. These patterns have been ascribed to blood vessels but the patterns are different from those seen with other staining techniques for blood vessels. It has recently been shown that microvessel density is the dominant prognostic factor in uveal melanoma. This study reinvestigates the nature and significance of the PAS patterns.

METHODS

The PAS patterns were compared with the patterns seen with conventional connective tissue stains and with the patterns seen in sections stained for the presence of blood vessels (by immunohistochemistry for factor VIII related antigen). The PAS patterns were determined on a panel of 117 cases of uveal melanoma. The prognostic significance of each of these patterns was determined and, as more than one pattern can exist in a tumour, principal components analysis was performed to determine the number of underlying factors.

RESULTS

Comparison of the PAS patterns with other stains demonstrates that they are based on connective tissue including fibrovascular tissue. Five of the nine PAS patterns carried prognostic significance on univariate analysis. Principal components analysis suggested that these patterns represented three underlying factors, which were tentatively identified as representing disordered growth (factor 1), emergence of rapidly growing subclones (factor 2), and section orientation (factor 3).

CONCLUSIONS

The PAS patterns are based on fibrovascular tissue and can be ascribed to three underlying factors. The first two of these factors carried prognostic significance and the first (disordered growth) retained independent prognostic significance in a multivariate Cox model which included microvessel density and tumour size.

Correlation of ultrasound parameter imaging with microcirculatory patterns in uveal melanomas

Previous studies demonstrated a correlation between acoustic backscatter parameters and survival in ocular melanoma. The histologic presence of microvascular networks in ocular melanoma is also associated with death from metastases. This study tests the hypothesis that melanomas grouped on the basis of these microvascular patterns are separable by ultrasound spectrum analysis. We scanned 40 melanomas using a 10-MHz ultrasound unit equipped for digitization of radio frequency data. After enucleation, tumors were sectioned in planes corresponding to the ultrasonographic examination and stained to demonstrate microcirculation. Acoustic spectral parameters were compared between 14 melanomas with a nevuslike microcirculation and 26 with foci of high-risk microvascular structures. Smaller scatterer size, lower acoustic concentration and greater spatial variability were found to correlate with high-risk microvascular patterns and areas of cystic degeneration. We suggest that nonvascular extracellular matrix components associated with microvessels may be responsible for the correlation of acoustic parameters with microvascular pattern and distribution.

Prognostic parameters in uveal melanoma: a review

Histologic cell type, largest tumor diameter and tumor location have traditionally been regarded as the leading predictors of survival for uveal melanoma. Morphological cell typing is, however, subjective to variations in interpretation. More objective classification parameters have emerged from extensive cytomorphometrical and DNA flow cytometrical studies. For patients with uveal melanoma there is no effective therapy if metastases have developed, and the median survival after clinical diagnosis of hepatic metastases is extremely poor. Current research focuses on the mechanisms underlying the metastatic process, including tumor vasculature, cytogenetics, oncogene activation, immunology, melanoma-associated antigens and tumor cell migration (cell-cell and cell-matrix interaction). Several new prognostic parameters have emerged from these studies, such as closed vascular patterns, loss of one chromosome 3, and different indices of cell proliferation. Furthermore, considerable genotypical and phenotypical differences have been found between uveal and cutaneous melanoma. In prospective studies on large series of melanomas a combination of histopathological and/or clinical prognostic parameters might be selected with high sensitivity and specificity, providing a way of selecting patients at high risk of developing metastatic disease, who might be eligible for adjuvant therapy.

Metastatic uveal melanoma. A morphologic and immunohistochemical analysis

BACKGROUND

Uveal melanoma often metastasizes late and preferentially to the liver, in contrast to cutaneous melanoma. The objective of the current study was to evaluate the histopathologic and immunohistochemical changes in primary uveal melanomas and their corresponding metastases.

METHODS

The morphology and immunohistochemical reactivity for the melanoma-associated antibodies HMB-45, S-100 protein, and NKI-C3 were assessed for 29 primary uveal melanomas and their corresponding metastatses.

RESULTS

A significant difference in cell type of the primary and the metastatic uveal melanoma was found (P = 0.0001). The metastases derived from the 29 patient's revealed 82.5% epithelioid or nonclassifiable cells. Positive staining of the primary uvea melanomas and their metastases was found to be 93% and 91%, respectively, for HMB-45, 80% and 66%, respectively, for S-100, and 56% and 71%, respectively, for NKI-C3.

CONCLUSIONS

Metastases of uveal melanomas are comprised of a higher grade of malignant cell types. Nonclassifiable cells can be observed in 40% of metastatic lesions. In the current study, HMB-45 proved to be the most sensitive immunohistochemical marker in the analysis of metastatic uveal melanoma and should be used as part of a panel of monoclonal antibodies in the analysis of any metastatic tumor of unknown origin.

Prognostic value of morphometric features and the callender classification in uveal melanomas

PURPOSE

Cytomorphometric analysis of uveal melanoma has focused on nucleolar characteristics, although nuclear measurements are easier and more reproducible. In this study, we examine a restricted set of nuclear and nucleolar cytomorphometric variables in the search for the most quantifiable and reproducible prognostic parameter among these and discover a means of assessing the malignancy of tumors within the different Callender subgroups.

METHODS

Uveal melanomas from 94 patients with a minimum follow-up of 5 years underwent nuclear and nucleolar morphometric analysis using a digitized interactive video overlay system. Statistical analysis included univariate and multivariate survival analysis on morphometric variables and classic prognostic parameters (such as Callender cell type, size, etc.).

RESULTS

Univariate analysis of cytomorphometric parameters showed the standard deviation of nuclear area (NASD) to be the most significant variable (P < 0.0001: Mantel-Cox, 15.2). This was followed by the difference between nuclear and nucleolar areas (P < 0.002; Mantel-Cox, 9.5), the standard deviation of nucleolar area (SDNA) (P < 0.01; Mantel-Cox, 6.4), and the standard deviation of the shortest nuclear axis (P < 0.02; Mantel-Cox, 6.4). There was a trend for significance with the mean of the ten largest nucleoli (P < 0.07). Multivariate analysis of clinical and cytomorphometric variables showed improvement of prognostic prediction with a combination of the NASD, largest tumor dimension, and glaucoma (P < 0.0001; Mantel-Cox, 26.3). Callender cell type was strongly correlated with the NASD (P < 0.0002), the mean axis ratio of the nuclear area (P < 0.0007), and the mean of the ten largest nucleoli (P < 0.0007).

CONCLUSION

Cytomorphometric analysis of uveal melanoma should include nuclear area and may identify tumors of differing malignancy within the same Callender class.

Histologic findings and prognosis of uveal malignant melanoma in japanese patients

PURPOSE

To determine factors of uveal malignant melanoma that would help to predict prognosis in Japanese patients.

METHODS

From 1969 to 1994, 23 eyes with uveal malignant melanoma were enucleated from 23 Japanese patients, and 16 of these patients were studied. In the 16 patients, enucleated eyes were evaluated for tumor characteristics, including cell type and microvascular architecture. Patient records were reviewed for follow-up therapy and outcome. Mortality rate was evaluated four years after enucleation.

RESULTS

In Japanese patients with uveal malignant melanoma, the average tumor size was larger (average largest diameter, 11.36 mm; average increase, 6.25 mm) and the average patient age was younger (55.2 years old) than previously reported for white populations. Patients with spindle cell type melanoma tended to have a better prognosis than those with epithelioid cell type (four-year mortality rates: spindle cell type, 0%; mixed cell type, 43%; epithelioid cell type, 66%). Microvascular architecture patterns interpreted as either network or closed loop patterns were associated with a poorer prognosis (network pattern, P = .03; closed loop pattern, P = .005).

CONCLUSIONS

The prognosis for Japanese patients with uveal malignant melanoma is poorer, and epithelioid cell-type melanoma is more common, than has been reported in white populations. Mitotic figures are well correlated with poor prognosis, as are two microvascular patterns, the network pattern and the closed loop pattern.

Technique for the digital imaging of histopathologic preparations of eyes for research and publication

BACKGROUND

Although there are excellent techniques to photograph gross ocular pathology specimens, it is difficult to view or photograph the entire eye from a glass slide using equipment designed for photomicrography. This investigation was initiated to develop a technique to image the entire eye from a glass slide.

METHODS

The glass histopathologic slide, placed in a carrier intended for 35-mm film transparencies, is inserted into a 35-mm slide scanner. The glass slide is scanned, creating a digital color image which may be converted to black and white with enhancement of certain histologic features. One may use a digital film recorder to produce 35-mm photographic transparencies or a dye sublimation printer to produce high-resolution color or black and white prints.

RESULTS

More than 400 ocular whole-mount preparations have been digitized in the authors' laboratory to generate illustrations suitable for publication or for analysis in morphologic research.

CONCLUSION

Digital techniques provide easier control over density and contrast than conventional photographic methods. Digitized images are well-suited for morphologic analyses in research. These techniques allow one to publish black and white photographs for books or journals while retaining the original color image for potential CD-ROM editions.