Rare Anterior Segment Retinoblastoma Masquerading as Corneal Endotheliitis.

We present a unique case involving a 6-year-old female with a unilateral corneal endotheliitis-like finding, who was ultimately found to have a form of anterior diffuse infiltrating retinoblastoma with no evidence of retinal involvement. The patient's presumed endotheliitis was initially treated with topical dexamethasone and oral acyclovir without improvement. She then underwent multiple fine-needle aspirations of anterior chamber fluid, which were negative for abnormal findings of viral polymerase chain reaction, viral cultures, and flow cytometry. Months after initial presentation, an anterior chamber angle mass developed and a biopsy identified retinoblastoma cells. The patient underwent plaque radiotherapy of the cornea and systemic chemotherapy. The patient regained good vision and is tumor-free at 13 months. Anterior inflammation is a rare form of masquerade syndrome associated with retinoblastoma; however, it tends to be associated with diffuse posterior segment retinoblastoma when it does occur. Diffuse anterior retinoblastoma is a rare form of retinoblastoma with no apparent focus in the retina. Ultimately, our patient developed an anterior chamber angle lesion, which was biopsied and proven to be retinoblastoma. Unusual corneal endotheliitis-like findings in children that are not responsive to conventional treatment should raise the clinician's suspicion of malignancy, even when no retinal lesion is detected.