Ciliary Body Medulloepithelioma: Clinical and Pathologic Challenges with a Focus on Molecular Genetics

Objective: Ciliary body medulloepithelioma (CBME), a pediatric intraocular tumor with potential for locally aggressive behavior and metastasis, may present with a diverse spectrum of clinical and histopathologic features leading to diagnostic and management challenges. Examination of unusual CBME cases highlights challenges and modern diagnostic techniques which facilitate accurate diagnosis and guide management. Methods: A retrospective clinicopathologic analysis of 6 patients with unusual clinical or pathologic features of CBME was performed. Results: The mean duration of delay in accurate diagnosis was 5.7 years (SD: 8.2, median: 3, range: 0–22). All patients developed cataract, 4 (67%) were diagnosed with glaucoma, and 4 (67%) underwent surgery prior to accurate diagnosis. At initial presentation, only one patient with a known history of genetically confirmed DICER1 syndrome underwent appropriate imaging leading to a timely identification of a ciliary body mass and no delay in diagnosis. Following identification of intraocular mass, 4 (67%) patients underwent enucleation. Two patients (33%) underwent exenteration for extraocular extension of CBME. Initial histopathologic differential diagnosis included CBME, melanoma, adenoma or adenocarcinoma of the pigmented ciliary body epithelium, retinoblastoma, sarcoma, and malignant teratoma. Immunohistochemistry and genetic testing assisted in the diagnosis of CBME. Two patients (33%) had a germline DICER1 variant; this was known prior to CBME diagnosis in one patient and discovered after CBME diagnosis in the second patient. Conclusion: This series highlights the unusual clinical and histopathologic features of CBME that contribute to delays in diagnosis. Modern aids including genetic testing, ancillary imaging studies, and immunohistochemistry facilitate a timely accurate diagnosis of CBME and guide management.