Rhegmatogenous retinal detachment secondary to isolated retinal metastasis from small cell lung carcinoma: An uncommon complication

Introduction

The metastatic carcinoma to the eye is commonly located in choroid, but rarely in retina. Most of the retinal metastases were reported to be originated from cutaneous melanoma. ¹ Retinal metastasis is limited to a few cases in the literature.^1,2 These cases on retinal metastasis have demonstrated different posterior segment findings such as whitish retinal mass lesion, vitreous or retinal hemorrhage, exudative retinal detachment (RD), and intraretinal exudation. ¹ Clinical experience with retinal metastases remains insufficient because retina is uncommon location for metastasis. Therefore, familiarity with the findings of retinal metastasis is of great importance in terms of early diagnosis and treatment.

Herein, we report a case of rhegmatogenous RD (RRD) associated with isolated retinal metastasis as an uncommon complication.

Case report

A 56-year-old man was referred to our clinic with the diagnosis of extrafoveal choroidal neovascularization (CNV) in the left eye (LE) and had three anti-vascular endothelial growth factor (anti-VEGF) injections to the LE, which resulted in 20/20 vision, and he had been followed up since then with wait and extend regimen. He was lost from follow-up for a year and then came back with the complaints of floaters and progressive diminution of vision starting from the superonasal visual field in his right eye (RE) over the past 2 weeks. His history during this period revealed that he was diagnosed with small cell lung cancer 8 months ago and had lobectomy operation followed by chemotherapy, including cisplatin and etoposide during this period. He was a heavy smoker. The ophthalmologic examination of the LE was unremarkable and stable with a scar of extrafoveal CNV with full vision and no activity sign of CNV in spectral-domain optical coherence tomography (SD-OCT, Heidelberg Spectralis, Germany). However, visual acuity was counting fingers from 4 m in the RE with unremarkable anterior segment examination findings. Fundus examination revealed an inferotemporal RD involving macula associated with multiple whitish colored retinal lesions. These lesions were retinal masses, the largest one measuring 6 mm × 5 mm located 6 mm temporal to the fovea and the smaller one measuring 3 mm × 6 mm located 9 mm inferior to fovea, and the smallest one being in between these two lesions in the RE (blue arrows in Figure 1(a)). All lesions had obvious intrinsic vasculature and small areas of intraretinal hemorrhages. Two small spindle-shaped retinal breaks were found in the superior and temporal border of the temporal larger mass lesion (red arrows in Figure 1(a)).

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Figure 1.

(a) Wide-field fundus imaging of the RE: Note the inferotemporal retinal detachment involving macula and whitish colored retinal masses (blue arrows). Two small spindle-shaped retinal breaks were found in the superior and temporal border of the largest mass lesion (red arrows). (b) Orbital MRI demonstrating an isolated retinal mass without any adjacent metastatic spread (red arrow). (c) Wide-field fundus imaging following chemoradiotherapy. Note the decrease in amount of subretinal fluid and the size of retinal metastasis and retinal tears. (d) Ultrasonography demonstrates total RD with retinal metastasis without any choroidal involvement.

Positron emission tomography–computed tomography (PET-CT) and cranial magnetic resonance imaging (MRI), performed to screen for metastasis, demonstrated no recurrence of the tumor or metastasis elsewhere. Orbital MRI confirmed the isolated retinal mass without any choroidal or orbital involvement (Figure 1(b)).

After detection of retinal metastases, he was suggested to begin second-line treatment of the chemotherapy, including carboplatin and paclitaxel once a week, and low-dose prophylactic cranial radiotherapy. He received six cycles of systemic chemotherapy and 25 Gy of cranial radiotherapy with his written informed consent. No surgical intervention like retinal biopsy was scheduled in the first step since there was no doubt about the diagnosis.

The ophthalmic examination 2 months after the start of the second-line chemotherapy revealed some improvement in visual symptoms and decrease in the amount of subretinal fluid. There was also a decrease in size of preexisting retinal metastases and retinal tears (Figure 1(c)). He had some dry eye symptoms then. He came back 8 months later after having surgery for removal of adrenal gland because of metastasis. He was still receiving chemotherapy. Visual acuity of the RE decreased to hand motions level. Ultrasonography revealed the same retinal metastatic lesions with total RD without any choroidal involvement at this last visit (Figure 1(d)). He was still alive at the second year of follow-up.

Discussion

Differential diagnosis of the metastatic spread to retina can be challenging, in patients with no history of malignancy or unknown primary tumor. ³ Isolated retinal metastasis may be misdiagnosed as infectious or inflammatory retinitis because of its clinical picture as subretinal fluid, and subretinal and intraretinal exudation.^1,4 If there is a doubt in the diagnosis, retinal biopsy may be carried out for histopathological confirmation at this point. ⁵ A retinal biopsy was not considered for the presented case since the diagnosis was obvious with the presence of a known lung cancer and lack of other signs of inflammation such as vitritis and hemorrhage.

Previous studies have demonstrated various features related to the appearance and complications of retinal metastases. Mack et al. ⁶ have reported that cutaneous melanoma–associated retinal metastases and vitreous seeds look brown in color, whereas carcinoma-derived retinal metastasis looks whitish with perivascular infiltration. Shields et al. ¹ have underlined that retinal metastatic tumors secondary to lung and esophageal carcinoma are white, those secondary to breast carcinoma are yellow in color. They have also reported that the retinal metastases originating from cutaneous melanoma are nodular and yellow or brown in color, and are complicated with vitreous hemorrhage. In the presented case, the retinal metastases were white in color, as reported before, and were complicated with RRD. To the best of our knowledge, this is the first case of retinal metastasis associated with RRD in literature.

Presumably, it is assumed that retinal tears occurred due to tangential force caused by the contraction of the retinal mass. However, in case of previously existing but asymptomatic retinal breaks, exudative RD secondary to intraocular metastasis could extend to these retinal breaks and then the detachment could transform to an RRD. This is not the case in the presented case probably since he was being followed for a CNV in the fellow eye and had complete retinal examination a year before this problem in the RE. In addition, location of the retinal breaks just near the metastasis and absence of marked exudation suggest that the retinal breaks developed newly, not preexisting.

Presence of retinal metastasis suggests that spread of primary tumor to other organs will happen shortly if left untreated. Previous case reports have also suggested significant increase in the frequency of de novo intracranial metastasis after the development of ocular spread. ⁷ Therefore, early diagnosis and treatment of retinal metastasis are crucial to improve the quality of patient’s life, and restore or protect the vision. Treatment for metastatic disease is accepted to be palliative. A small number of treatment options, including chemotherapy, radiotherapy, enucleation, photodynamic therapy, and intravitreal injection of bevacizumab, have been used so far for the treatment of ocular metastasis.^1,8,9 Since ocular metastasis usually occurs in end-stage metastatic disease, the prognosis is usually guarded, and systemic condition and life expectancy are poor in these cases. However, in the presented case, retinal spread was the first finding of metastatic disease in contrary to the literature.

Conclusion

To the best of our knowledge, this is the first case, which reports retinal metastasis from a lung cancer associated with RRD. We emphasize that retinal metastasis originating from lung cancer can create tangential force on the retina by tumor contraction leading to retinal tears adjacent to the metastatic lesions and RRD. Regression of metastasis with chemoradiotherapy may cause the retinal tears to shrink and temporary stabilization of the RD; however, the visual prognosis is usually poor.