UNASSIGNED: This work aims to report the challenging diagnosis, treatment, and follow-up of a patient with persistent fetal vasculature (PFV) and retinoblastoma (RB).
UNASSIGNED: A 22-month-old boy presented with unilateral RB stage VB in the right eye and PFV in both eyes. The patient was treated with transpupillary laser ablation and systemic chemotherapy.
UNASSIGNED: Treatment resulted in complete tumor regression. Two years after the last systemic chemotherapy treatment, magnetic resonance imaging (MRI) showed increased signal intensity with progressive optic nerve enhancement, where intraneural malignancy could not be excluded. Enucleation of the right eye was performed. Histopathologic review showed no residual active malignancy in the enucleated globe.
UNASSIGNED: This case demonstrates the importance of a thorough clinical examination to establish the correct diagnosis and to rule out RB before any surgery. This case also highlights the importance of regular follow-ups after tumor regression with full a ophthalmologic examination, B-scan, and periodic MRI.

Retinoblastoma mimickers, or pseudoretinoblastoma, are conditions that show similarities with the pediatric cancer retinoblastoma. However, false-positive retinoblastoma diagnosis can cause mistreatment, while false-negative diagnosis can cause life-threatening treatment delay. The purpose of this study is to identify the MR imaging features that best differentiate between retinoblastoma and the most common pseudoretinoblastoma diagnoses: Coats\' disease and persistent fetal vasculature (PFV). Here, six expert radiologists performed retrospective assessments (blinded for diagnosis) of MR images of patients with a final diagnosis based on histopathology or clinical follow-up. Associations between 20 predefined imaging features and diagnosis were assessed with exact tests corrected for multiple hypothesis testing. Sixty-six patients were included, of which 33 (50%) were retinoblastoma and 33 (50%) pseudoretinoblastoma patients. A larger eye size, vitreous seeding, and sharp-V-shaped retinal detachment were almost exclusively found in retinoblastoma (p < 0.001-0.022, specificity 93-97%). Features that were almost exclusively found in pseudoretinoblastoma included smaller eye size, ciliary/lens deformations, optic nerve atrophy, a central stalk between optic disc and lens, Y-shaped retinal detachment, and absence of calcifications (p < 0.001-0.022, specificity 91-100%). Additionally, three newly identified imaging features were exclusively present in pseudoretinoblastoma: intraretinal macrocysts (p < 0.001, 38% [9/24] in Coats\' disease and 20% [2/10] in PFV), contrast enhancement outside the solid lesion (p < 0.001, 30% [7/23] in Coats\' disease and 57% [4/7] in PFV), and enhancing subfoveal nodules (38% [9/24] in Coats\' disease). An assessment strategy was proposed for MR imaging differentiation between retinoblastoma and pseudoretinoblastoma, including three newly identified differentiating MR imaging features.

OBJECTIVE: To describe pathological features and determine the types and frequency of pseudoretinoblastoma simulating retinoblastoma in 70 enucleated eyes.
METHODS: Retrospective histopathologic analysis of consecutively enucleated eyes for presumed intraocular retinoblastoma during the past 11 years in the Second People\'s Hospital of Yunnan Province in China.
RESULTS: 9 of the 70 cases were found to be pseudoretinoblastoma on histological analysis. 4 cases were Coat\'s disease, 2 cases were uveitis and the rest 3 cases were respectively identified as vitreous hemorrhage, toxocariasis and retinal dysplasia. Clinical features and pathological features of these cases were described in detail.
CONCLUSIONS: Coat\'s disease accounted for the most common conditions (44.5%) of pseudoretinoblastoma, uveitis (22.2%) accounted for less common conditions, toxocariasis (11.1%), vitreous hemorrhage (11.1%) and retinal dysplasia (11.1%) presented in a sporadic form in our pseudoretinoblastoma series. They have distinctive histopathological features to differentiate from retinoblastoma.

BACKGROUND: Incontinentia pigmenti is a rare X-linked dominant syndrome caused by mutation in the NEMO/IKKgamma gene, and characterized by a spectrum of cutaneous, ocular, neurologic and dental abnormalities. In the eye, findings include retinal vascular non-perfusion, occasionally with traction retinal detachment, retinal fibrosis, and retinal pigment epithelium defects. These findings can resemble retinoblastoma, especially when vitreoretinal fibrosis produces leukocoria.
METHODS: A 2-month-old girl born full-term presented with leukocoria, suspicious for retinoblastoma. She was found to have an ischemic retrolental fibrovascular retinal detachment. In addition, there was linear cutaneous hyperpigmentation, diagnostic of incontinentia pigmenti.
CONCLUSIONS: Retinoblastoma can be a challenge to diagnose. There are numerous simulating lesions that can present with leukocoria and retinal detachment, including incontinentia pigmenti. Recognition of the cutaneous features of incontinentia pigmenti contributes to early detection of related ophthalmologic, neurologic and dental abnormalities.