Cyst-like recurrence of retinoblastoma diagnosed by multimodal imaging

Abstract

Purpose: To illustrate the diagnosis and management of an atypical, cyst-like recurrence of retinoblastoma.

Observations: A 4-month-old boy was diagnosed with Group B retinoblastoma in the right eye, consisting of a 10 x 9 × 3.6 mm retinal tumor temporal to the macula. He was treated with one session of intra-arterial ophthalmic artery chemotherapy using melphalan, followed by three sessions of diode laser transpupillary thermotherapy (TTT), after which complete tumor regression was achieved. 45 weeks after initial treatment, a cystic lesion was detected adjacent to superior margin of the regressed tumor scar. The differential diagnosis included pigment epithelial detachment, retinal gliosis, secondary retinoschisis, and local tumor recurrence. Multimodal imaging including OCT angiography confirmed the diagnosis of local recurrence manifesting as a vascularized cyst-like lesion. Two additional sessions of TTT achieved sustained tumor regression through 16 months of additional follow-up.

Conclusions and importance: Recurrence of retinoblastoma following chemotherapy typically manifests as enlargement of a previously regressed tumor, or seeding into the vitreous or subretinal space. An unusual cyst-like recurrence of retinoblastoma at the margin of a previously regressed tumor was diagnosed by multimodal imaging. Focal diode laser transpupillary thermotherapy was curative.

Keywords: Fluorescein angiography; Intra-arterial chemotherapy; Optical coherence tomography; Retinoblastoma; Transpupillary thermotherapy.

Fig. 1

Initial presentation of unilateral retinoblastoma. A. At presentation, fundus photography (RetCam, Clarity Medical Systems) showed a white vascularized retinal tumor in the temporal macula. B. At presentation, B-scan ultrasonography (Aviso, Quantel Medical) revealed an elevated retinal tumor measuring 10 x 9 × 3.6 mm with intralesional calcifications and intrinsic vascularity. C. At 21 weeks after one session of intra-arterial chemotherapy with melphalan, followed by three sessions of diode laser transpupillary thermotherapy, the tumor was markedly regressed. D. Ultrasonography at that time demonstrated a plaque-like calcified tumor remnant with no evidence of residual viable tumor.

Fig. 2

Multimodal imaging of cyst-like tumor recurrence. A. At 45 weeks after initial treatment, a cyst-like retinal lesion (arrows) was identified at the superior edge of the regressed primary tumor. B. Fluorescein angiography demonstrated abnormal vascularity and leakage within the cystic lesion, which appeared arise from a vascularized remnant at the nasal edge of the original tumor. C. Optical coherence tomography (OCT) (Spectralis, Heidelberg Engineering, Germany) showed that the cyst-like lesion consisted of an irregularly thickened floor and dome-shaped roof, with effacement of the normal retinal layers. D. OCT angiography (OCTA) demonstrated that the abnormal blood vessels were located mostly within the roof of the lesion within the superficial vascular complex.