A Case of Inflammatory Juvenile Conjunctival Nevus with a Rare Histopathological Type.

Introduction: Inflammatory juvenile conjunctival nevus (IJCN) is a rare condition affecting both children and adolescents. It has misleading clinical and histopathological features; therefore, careful assessment is necessary. We present a case of IJCN with a rare pathological type and misleading histopathological features.

Case presentation: A 13-year-old girl with IJCN in the right eye was treated with antiallergic and steroid eye drops but showed no response and was referred to our hospital for excisional biopsy. Slit-lamp examination revealed a nonpigmented juxtalimbal tumor in the right eye. Histopathologically, nevus cells with mild nuclear atypia proliferated within the conjunctival epithelium. Confluent growth of junctional nests, conjunctival cysts, and prominent inflammatory infiltration were also observed. Considering the young age of the patient and immunohistochemical characteristics (HMB-45, SOX10, p16 and Ki-67), the patient was finally diagnosed with IJCN. IJCN has three pathological subtypes - compound, subepithelial, and junctional - depending on the location of the nevus cells. This case was diagnosed as a rare junctional type, as most of the examined sections only showed lesions within the epithelium; no lesions were clearly identified extending beneath the epithelium.

Conclusion: The pathological diagnosis of IJCN is difficult because some features of IJCN suggest malignancy. Detailed microscopic examination, immunohistochemical staining, and the patient's young age helped render a final diagnosis.