Iris melanomas. Diagnostic problems

Pathological and Molecular Diagnosis of Uveal Melanoma

(1) Background: Uveal melanoma (UM) is a common malignant intraocular tumor that presents with significant genetic differences to cutaneous melanoma and has a high genetic burden in terms of prognosis. (2) Methods: A systematic literature search of several repositories on uveal melanoma diagnosis, prognosis, molecular analysis, and treatment was conducted. (3) Results: Recent genetic understanding of oncogene-initiation mutations in GNAQ, GNA11, PLCB4, and CYSLTR2 and secondary progression drivers of BAP1 inactivation and SF3B1 and EIF1AX mutations offers an appealing explanation to the high prognostic impact of adding genetic profiling to clinical UM classification. Genetic information could help better explain peculiarities in uveal melanoma, such as the low long-term survival despite effective primary tumor treatment, the overwhelming propensity to metastasize to the liver, and possibly therapeutic behaviors. (4) Conclusions: Understanding of uveal melanoma has improved step-by-step from histopathology to clinical classification to more recent genetic understanding of oncogenic initiation and progression.

Imaging of Anterior Segment Tumours: A Comparison of Ultrasound Biomicroscopy Versus Anterior Segment Optical Coherence Tomography

Anterior segment tumours of the eye are relatively rare but can pose significant morbidity and mortality. We conducted a literature review to compare the performance of ultrasound biomicroscopy to anterior segment optical coherence tomography in the imaging of these tumours. A total of seven studies were included accounting for a cumulative 1,114 eyes. Ultrasound biomicroscopy has traditionally formed, and remains, the mainstay of tumour imaging due to its ability to penetrate pigmented lesions and delineate the posterior border of tumours, and the current evidence supports this.

Clinical and ultrasound biomicroscopy features associated with growth in iris melanocytic lesions

PURPOSE

To determine the clinical and ultrasound biomicroscopy (UBM) features associated with growth in iris melanocytic lesions.

STUDY DESIGN

Retrospective case series analysis.

METHODS

We included all iris melanocytic lesions that were monitored between January 2005 and November 2009. At the end of the analysis, 44 eyes of 44 patients were included in the final analysis. The clinical features analyzed were: iris color, largest base diameter, radial location of the lesion epicenter, circumferential location of the lesion epicenter, lesion configuration, lesion pigmentation, intrinsic vascularity within the lesion, presence of associated pigmentation, the impact on the pupil, presence of iris atrophy, and lesion-induced localized cataracts. The UBM features included lesion thickness, presence of corneal touch, presence of surface plaque, internal structure, and internal reflectivity. Regression analysis was performed to define the features associated with growth.

RESULTS

Twenty-three percent of the lesions showed documented growth. Mean follow-up was 21.4 months (range: 10-48). Clinical features associated with growth were a large basal diameter at baseline (P = .004) and inferior location (P = .004). UBM features associated with growth were: a greater baseline thickness (P = .01), presence of corneal touch (P = .007), an irregular internal structure (P = .0001), and the presence of dots and linear streaks (P < .0001). Clinical features that were not associated with growth were the radial location of the lesion in the iris (P > .999), lesion configuration (P > .999), lesion pigmentation (P > .999), the presence of pigment dispersion (P = .70), iris freckles (P = .15), corectopia (P > .999), ectropion (P > .999), and intrinsic vascularity (P = .70). UBM features not associated with growth were the presence of a surface plaque (P = .07) and the internal reflectivity (P = .77).

CONCLUSION

Substantial growth in iris melanocytic lesions is associated with original larger basal diameter and inferior lesion location. On UBM growth is associated with greater original thickness, presence of corneal touch, and an irregular internal structure. Presence of these features could modify the frequency of observation of those lesions.

Anterior segment tumor biopsy using an aspiration cutter technique: clinical experience

PURPOSE

To report the results and complications of an aspiration cutter-assisted anterior segment tumor biopsy performed under viscoelastic.

DESIGN

Retrospective, consecutive, interventional case series.

METHODS

Fifty-five patients with anterior segment tumors underwent aspiration cutter-assisted biopsy at a single center. Fifty-six biopsies were performed, because 1 eye underwent biopsy twice. Indications for biopsy included: suspected anterior segment malignancy, patient's desire for pathologic confirmation before treatment, atypical tumor, and genetic tumor analysis. The main evaluated outcomes were the perioperative visual acuity, the biopsy technique, and related complications.

RESULTS

The initial sample comprised 55 consecutively biopsied patients, from which a minimum 1-month follow-up existed for 52 biopsy samples. The median total follow-up was 30.4 months (range, 1 to 190 months). The mean initial visual acuity was 20/50 before and 20/50 1 month after biopsy. No patient lost vision. Most cases were suspected iris melanoma (n = 39/56; 69.6%), followed by suspicious iris nevi (n = 4/56; 7.1%) and melanocytoma (n = 4/56; 7.1%). Seven (n = 7/52; 13.4%) wounds required a single 10-0 nylon suture to achieve negative Seidel test results at the corneal entry site. Postoperative surgical findings included transiently increased intraocular pressure (n = 6/52; 11.5%), 1 hyphema, 1 flare, and 1 persistent pupillary defect. All but the pupillary defect resolved within 4 weeks of the biopsy procedure. There were no secondary infections or cataracts.

CONCLUSIONS

This study suggests that small-incision, aspiration cutter-assisted anterior segment biopsy seems to be a safe and effective procedure. No short- or long-term complications that would prevent its use were noted.

Estimating the risk of malignant transformation of a choroidal nevus

PURPOSE

To estimate the risk of malignant transformation of a choroidal nevus in the white population.

DESIGN

Systematic literature review.

METHODS

A literature review was performed to obtain data on the prevalence of choroidal nevi in the white population. Data from studies that used indirect ophthalmoscopy or otherwise corrected data to include the entire fundus were selected. Only studies reporting on the United States population were included. The number of affected individuals was estimated using 2000 U.S. census data. The estimate of annual incident choroidal melanoma cases in the corresponding age- and race-matched population was calculated using the Surveillance, Epidemiology, and End Result database (1973-2000). Average annual age-specific incidence rates for 1973 to 2000 for each of the 5-year age groups (adjusted for the U.S. 2000 population) were calculated and applied to the corresponding census data. The ratio of numbers of affected individuals with choroidal melanoma and choroidal nevi gave the annual rate of malignant transformation of a choroidal nevus.

MAIN OUTCOME MEASURES

Annual rate of malignant transformation of a choroidal nevus in the white population of the U.S.

RESULTS

The prevalence of choroidal nevus in the white U.S. population ranged from 4.6% to 7.9%. It was estimated that, on average, 8864625 individuals in the U.S. had a choroidal nevus. The number of individuals with choroidal melanoma in the corresponding age- and race-matched population ranged from 989 to 1008 (mean, 1002). The annual rate of malignant transformation of a choroidal nevus was estimated to be 1 in 8845.

CONCLUSIONS

If it is assumed that all choroidal melanomas arise from preexisting nevi, then the published data suggest a low rate (1/8845) of malignant transformation of a choroidal nevus in the U.S. white population.

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.

Ocular melanoma

This article reviews the current pathogenesis, molecular changes, diagnosis, and treatment of ocular melanomas. Ocular melanomas can involve the eyelid, conjunctiva, intraocular structures, and the orbit. The most common eye melanoma involves the uveal tract and is responsible for approximately 13% of melanoma deaths. Uveal melanomas account for 10% of all melanomas.

Ring melanoma of the anterior chamber angle: a report of fourteen cases

PURPOSE

Ring melanoma of the anterior chamber angle is a rare variant of uveal melanoma that manifests as circumferential, flat tumor growth predominantly confined to the trabecular meshwork and other anterior chamber angle structures. We report the clinical and histopathological features, management, and prognosis of ring melanoma of anterior chamber angle.

METHODS

A retrospective review of clinical features, management, histopathologic features, and prognosis was performed. Of 8800 patients with uveal melanoma examined on the Oncology Service at Wills Eye Hospital over a 25-year period, only 14 patients (0.2%; 14 eyes) were classified clinically as ring melanoma of the anterior chamber angle. In no case was there appreciable involvement of the iris or ciliary body on clinical examination.

RESULTS

The patients were followed elsewhere for a mean of 8 months before intraocular malignancy was suspected. Upon referral to the Oncology Service, the intraocular pressure was greater than 22 mm Hg in the affected eye in all patients (mean, 36 mm Hg; median, 35 mm Hg; range, 24 to 48 mm Hg), and all patients were using at least two glaucoma medications. The melanoma infiltrated the anterior chamber angle for a mean of 10 clock hours (range, 8 to 12 clock hours). Tumor management consisted of enucleation in 13 cases and plaque radiotherapy in one case. Histopathologic examination revealed epithelioid cell type melanoma in one case, mixed cell type in nine, and spindle cell type in four. Of the 13 patients who underwent enucleation, tumor cells were found within the Schlemm canal in all cases. Five cases displayed invasion of the intrascleral canals, and three showed episcleral invasion. With the exception of two recent cases, 12 patients were followed for a mean of 64 months (median, 47 months; range, 23 to 225 months). Distant metastasis to the liver was detected in three of 12 patients (25%) after a mean follow-up of 78 months (median, 70; range, 37 to 128 months).

CONCLUSIONS

Ring melanoma of the trabecular meshwork and angle structures is a rare variant of diffuse uveal melanoma. It often masquerades as unilateral glaucoma and can be difficult to recognize clinically unless careful comparative gonioscopy is performed. Despite the relatively small tumor volume, life prognosis is guarded with distant metastasis in 25% at mean 6 years follow-up.

Iris melanoma: risk factors for metastasis in 169 consecutive patients

OBJECTIVE

To identify risk factors that predict distant metastases of iris malignant melanoma.

DESIGN

Retrospective case series.

PARTICIPANTS

The participants included 169 consecutive patients with microscopically confirmed iris malignant melanoma managed on the Oncology Service at Wills Eye Hospital between 1974 and 1999.

MAIN OUTCOME MEASURES

The main outcome measure was the development of distant tumor metastasis. Cox proportional regression models were used to calculate the risk of eventual metastatic spread.

RESULTS

Of 1054 patients referred with suspicious iris melanocytic tumors (rule out malignant melanoma) over a 25-year period, 169 patients (16%) had microscopically proven iris melanoma, and the remainder (84%) had clinically diagnosed iris nevus. Of the patients with iris melanoma, the mean age at the time of diagnosis was 43 years (median, 45 years; range, 1-90 years). All patients were Caucasian. The mean tumor base was 6 mm (median, 5 mm; range, 1-17 mm), and mean tumor thickness was 2 mm (median, 2 mm; range, 1-4 mm). The mean number of clock hours of tumor involvement in the iris was four, tumor seeding on the iris was four, and tumor seeding into the anterior chamber angle was four. Extraocular extension was present in 10 eyes (6%). The tumor management consisted of local resection (iridectomy, iridocyclectomy, or iridocyclogoniectomy) in 102 patients (60%), enucleation in 51 (30%), plaque radiotherapy in 9 (5%), and observation in 7 patients (4%). Metastasis developed in nine patients (5%). Using Kaplan-Meier life table analysis, metastasis was found in 3% of patients at 5 years, 5% at 10 years, and 10% at 20 years. The clinical factors at initial evaluation predictive of eventual metastasis from iris melanoma included increasing age at diagnosis (P = 0.03), elevated intraocular pressure (P = 0.03), posterior tumor margin at angle or iris root (versus midzone) (P = 0.02), extraocular extension (P: = 0.02), and prior surgical treatment of the tumor elsewhere before referral (versus observation) (P = 0.006). The method of management (resection, radiotherapy, or enucleation) did not have an impact on metastasis.

CONCLUSIONS

Microscopically confirmed iris melanoma demonstrates distant metastasis in 5% of patients at 10 years follow-up. Metastases are more likely to develop in those patients who are older and show tumor features of iris root/angle location with elevated intraocular pressure and extraocular extension.