Pars Plana Vitrectomy and Endoresection of a Retinal Vasoproliferative TumorVitrectomy and Endoresection of Vasoproliferative Tumor FREE

Retinal vasoproliferative tumors are histologically benign–appearing vascular lesions that can lead to visual loss due to subretinal and intraretinal exudation, vitreous hemorrhage, and exudative or tractional retinal detachments.^{1 - 2} Differentiating between retinal vasoproliferative tumors and von Hippel-Lindau (VHL) disease–associated retinal hemangioblastomas is important for patient counseling and systemic monitoring. While these lesions may be differentiated by characteristic pathologic findings, obtaining tissue for accurate diagnosis prior to enucleation is rare, and retinal vascular lesions may be treated based on characteristic ophthalmic findings. In some cases in which the diagnosis is unclear, the diagnosis of VHL may be made by genetic testing for mutations in the VHL gene, a negative history of VHL disease–associated tumors (eg, renal cell carcinoma, pheochromocytoma), and a negative family history of VHL disease in some cases.^{3 - 6} Cryotherapy, plaque radiotherapy, and enucleation have been described for the management of retinal vasoproliferative lesions.^{1 ,7 - 8} We describe herein the surgical technique of pars plana vitrectomy and endoresection of 2 retinal vasoproliferative lesions associated with vitreous hemorrhage in 1 patient for diagnostic, therapeutic, and patient counseling purposes.

A 31-year-old healthy woman presented with a 2-month history of decreased vision in her right eye. Visual acuities were 20/50 OD and 20/20 OS. Her pupils were briskly reactive to light in both eyes; no relative afferent pupillary defect was seen. Slitlamp examination of the right eye revealed 2+ red blood cells in the anterior vitreous of the right eye. Dilated funduscopic examination of the right eye revealed a grade 2 vitreous hemorrhage (Figure 1) with 2 midperipheral, retinal vascular lesions with overlying hemorrhage and associated subretinal exudation. One lesion was located superotemporally and associated with a tortuous feeder vessel. A second, larger lesion was located inferotemporally. Findings of slitlamp and dilated funduscopy were normal in the left eye.

B-scan ultrasonography demonstrated a 3 mm (height) × 6 mm (base diameter) inferotemporal lesion. B-scan of the superotemporal lesion showed a flatter elevation profile, and A-scan evaluation showed high internal reflectivity of both lesions. Both lesions were concerning for possible retinal hemangioblastomas vs a retinal vasoproliferative lesion.

Fluorescein angiography demonstrated a large, tortuous feeder vessel entering the substance of the superotemporal tumor in arterial phase of the angiogram. In the venous and recirculation phases of the angiogram, there was a web of vascular channels with late hyperfluorescence and leakage from the vascular channels.

Because of concern for VHL-associated hemangioblastomas, ophthalmic genetic counseling was performed. Family history was unremarkable for von Hippel-Lindau disease. Subsequent genetic testing for deletions or point mutations in the VHL gene using relative quantitative polymerase chain reaction and VHL gene sequence analysis for all 3 exons of the VHL gene was also negative.

Given the unlikelihood of the patient having 2 retinal vascular lesions in the absence of VHL disease and the presence of a nonclearing vitreous hemorrhage, pars plana vitrectomy with endoresection of the tumors for pathologic diagnosis, systemic follow-up, and prognostic considerations were discussed with the patient. Other treatment modalities considered included photodynamic therapy, cryotherapy, and brachytherapy. However, the view was too poor for photodynamic therapy, and there was a concern for exudative retinal detachment with cryotherapy and brachytherapy. Radiation retinopathy and optic neuropathy, as well as the multifocality of the retinal vascular lesions, also made brachytherapy less desirable, particularly in the face of an unclear diagnosis.

First, an infusion cannula with a chandelier illumination system was secured 4 mm posterior to the limbus to ensure adequate visualization of the tumors for bimanual manipulation of retinal tissue. A standard 3-port, 20-gauge vitrectomy with scleral depression-assisted peripheral vitrectomy was performed to ensure that all vitreous adhesions overlying the tumor had been dissected freely. Confluent indirect laser was then applied 360° around the tumors to be resected. Endodiathermy was then performed to the tortuous vessels feeding the tumor. Two independent retinectomies were then performed using intraocular scissors to isolate the superotemporal and inferotemporal tumors, respectively. The superotemporal sclerotomy was then enlarged, and the specimens were placed in formalin for histologic evaluation. An air-fluid exchange was then performed, followed by instillation of 16% C₃F₈ gas. The retina remained fully attached at the conclusion of surgery.

Pathologic evaluation of the superotemporal tumor disclosed a vascular anomaly within the retina that consisted of multiple large vessels with multiple lumens and collagenous tissue. The surrounding retina appeared edematous but there were no cells consistent with hemangioblastoma.

Microscopic evaluation of the inferotemporal lesion showed a similar specimen with multiple large intraretinal vessels with thick walls. A lymphocytic infiltrate was also identified within the retina, surrounding some of the large telangiectatic vessels. Surrounding retinal edema was also seen in this specimen. In one region within the retina, there were pigmented cells present that appeared to correspond to an area of retinochoroidal adhesion noted during surgical excision.

The patient was treated with topical prednisolone acetate, 1%, 4 times per day, ofloxacin 4 times per day, and atropine, 1%, twice per day following surgery. She was also instructed to maintain face-down head positioning. At postoperative week 1, the patient's retina remained attached under gas with mild subretinal heme at the surgical resection sites. Visual acuity improved to 20/30 by postoperative week 5 following dissipation of most of the intraocular gas bubble. At this visit, the subretinal heme had resolved and excellent chorioretinal laser scarring was observed in the 2 areas of surgical resection.

At her final follow-up visit 9 months after surgery, visual acuity was 20/40 OD. Slitlamp examination revealed a mild posterior subcapsular cataract. The retina remained attached with good chorioretinal adhesion around the superotemporal and inferotemporal resection sites. There were no signs of recurrent vascular lesions at the resection sites or retinal periphery (Figure 2).

Retinal vasoproliferative tumors may be difficult to distinguish clinically from VHL disease–associated hemangioblastomas but the difference between these 2 entities is important for patient counseling and prognosis. Shields et al² described a series of 129 vasoproliferative tumors in 113 eyes of 103 patients and their ophthalmic disease associations, clinical features, and treatment modalities. These tumors were found to develop in association with congenital, inflammatory, vascular, infectious, and traumatic ocular conditions. While 49% of these tumors were observed, other lesions were treated with cryotherapy (42%), laser photocoagulation (5%), and plaque radiation therapy (2%). Both retinal vasoproliferative tumors and VHL disease–associated hemangioblastomas may lead to visual loss from intraretinal and subretinal exudation, vitreous hemorrhage, and exudative or traction retinal detachments. However, these entities may be distinguished by histopathology or by a history consistent with VHL disease (ie, history of renal cell carcinoma, pheochromocytoma, or family history of VHL disease).

The resected lesions from this patient revealed vascular lumens with surrounding collagenous tissue; this differentiated it pathologically from hemangioblastoma lesions, which feature abnormal capillarylike fenestrated channels surrounded by vacuolated foamy cells. Reactive glial cells may also be found in some hemangioblastomas.^{6 ,8}

Histopathologic assessment of retinal vasoproliferative lesions prior to enucleation has been rarely described in the literature. An enucleation specimen from a blind, painful eye showed a proliferation of spindle-shaped glial cells and small blood vessels embedded in a hyalinized stromal matrix.¹ Transscleral resection of retinal vasoproliferative tumors in 2 patients with suspected melanoma was reported; in these patients, pathologic examination revealed a benign glial cell proliferative process with secondary vasoproliferation.⁹ Endoresection of posterior segment tumors has been advocated as globe-conserving therapy for selected cases of choroidal melanoma.^{10 - 13} The techniques described for endoresection of choroidal melanoma bear some similarities to those described in this article including a complete pars plana vitrectomy and meticulous posterior hyaloid dissection. However, retinal reattachment with perfluorocarbon liquid and silicone oil was not required in our patient, as has been described in endoresection procedures for melanoma.¹³

Kreuser et al¹⁴ initially described successful endoresection of a juxtapapillary retinal angioma in a patient with VHL. Schlesinger et al¹⁵ subsequently described the internal en bloc resection of VHL-associated hemangioblastomas in 3 patients. A similar technique was used in this patient except that diathermy alone was used to close feeder vessels, whereas a combination of diathermy and suture ligation of the feeder vessels was used to maintain hemostasis during prior excision of VHL disease–associated hemangioblastomas. Air-fluid exchange, laser photocoagulation, and gas tamponade were also used in this case to maintain retinal attachment postoperatively.

The patient's need for pars plana vitrectomy to remove the vitreous hemorrhage and the concern for VHL disease–associated hemangioblastomas were important factors in our recommendation to proceed with pars plana vitrectomy and endoresection of the tumor. The peripheral location of the tumors also made them more amenable to surgical excision with minimal visual sequelae. The histology of both tumors was most consistent with retinal vasoproliferative lesions, and these findings were important for patient counseling from visual and systemic health perspectives. Although our patient's postoperative course was uneventful, risks inherent to this procedure include pain, bleeding, infection, retinal detachment, and tumor recurrence. These risks were discussed with the patient in detail, and while other options (observation, photodynamic therapy, cryotherapy, brachytherapy) were strongly considered, their attendant risks, the patient's desire for visual rehabilitation, the effect of a definitive diagnosis for the patient's perspective on systemic health, and the potential need for future VHL disease screening played a role in the decision to proceed with surgical management.

In summary, we have described the successful management of retinal vasoproliferative lesions using pars plana vitrectomy, endoresection, laser, air-fluid exchange, and long-acting gas tamponade. This surgical procedure may potentially be beneficial for select patients with retinal vascular lesions for diagnostic and therapeutic purposes.

Correspondence: David J. Wilson, MD, Department of Ophthalmology, Eye Pathology Laboratory, Casey Eye Institute, 3375 SW Terwilliger Blvd, Portland, OR 97239-4197 (wilsonda@ohsu.edu).

Submitted for Publication: September 19, 2009; final revision received January 19, 2010; accepted February 8, 2010.

Financial Disclosure: None reported.

Funding/Support: This study was supported by an unrestricted grant to the Casey Eye Institute from Research to Prevent Blindness.

Previous Presentations: This research was presented in part at the J. D. M. Gass Fluorescein Angiography Meeting; November 2008; Atlanta, Georgia.