Clinical, Imaging, Pathological, and Molecular Details of an Unusual Uveal Melanocytic Tumor of Childhood.

Introduction: Uveal melanomas are rare and usually detected in adults over 60 years old. We presented herein an unusual intraocular melanocytic tumor that does not fit into any known category in a child with 10-year follow-up data. The clinical findings, course, ultrasound, MRI, and pathology, including immunohistochemistry and gene profiling, of a child with pigmented intraocular masses simulating uveal melanoma are described. The tumor is provisionally called "endopapillary uveal melanocytic tumor of childhood" based on its unusual pathology and molecular biology. Comprehensive molecular testing, including MSK-IMPACT, which interrogates 468 known cancer genetic alterations, and Archer fusion testing (RNA sequence analysis) revealed no abnormalities. Case Presentation: Our patient was a 7-month-old white boy with a suspected mass in the left eye. There was no family history of melanoma. An MRI scan revealed a 1.9 × 1.7-cm well-circumscribed, heterogeneously T1 pre-contrast hyperintense mass, which demonstrated heterogeneous low signal intensity on T2-weighted imaging. A needle biopsy using a 25-gauge needle revealed a pigmented tumor, so we performed an enucleation. Upon histopathologic examination after enucleation, the tumor was densely pigmented, without significant necrosis or internal cavitation. Tumor cells grew around vascular "papillae." Six years later, the patient is alive and shows no evidence of local or systemic recurrence. Conclusion: Our case exhibited unique features and pathology, without any of the known genetic abnormalities associated with uveal melanoma and does not match the descriptions in the existing literature. Thus, we have named these masses "endopapillary uveal melanocytic tumor of childhood."