Inflammatory juvenile compound conjunctival nevi. A clinicopathological study and literature review

The conjunctival nevus affecting children and adolescents is a rare condition and the literature showed only few reports on this issue. The aim of this article is to determine the histopathological features for the correct diagnosis of an inflammatory juvenile compound nevus of the conjunctiva (IJCNC) in order to make the difference between this tumor and other lesions, like conjunctival melanoma or lymphoma, very similar from a gross point of view. This article is a clinical pathological study of two cases of IJCNC with particular histopathological characteristics, who were admitted at the 2nd Ophthalmology Clinic, "Prof. Dr. Nicolae Oblu" Emergency Clinical Hospital, Iasi, Romania, over a period of five years (from July 1, 2012 to June 30, 2017). Both patients were adolescents, a boy (13-year-old) and a girl (12-year-old). Both lesions were bulbar juxtalimbal located and grew in size over one year. Seen at slit-lamp biomicroscopy, the first one presented as a non-pigmented lesion, while the second was a pigmented nevus, but their dimensions did not exceed 10 mm in diameter. From a histopathological point of view, both of them showed a nested junctional growth pattern, along with intra- and subepithelial location, of the nevomelanocytes. Tumoral cells demonstrated different degrees of atypical cytology, but in the second case, it was more obvious. Microscopic examination also revealed epithelial cystic inclusions, and prominent inflammation in the stroma of these two nevi. One of the cases presented heavy inflammation that took the form of lymphoid follicles and sheets of eosinophils, but the other showed only diffuse inflammation with lymphocytes plasma cells, and eosinophils within its stroma. The immunohistochemical characterization (anti-melan A, anti-S100 protein and anti-cytokeratin AE1÷AE3 antibodies) of the tumoral cells helped to the diagnosis.

IJCNC represent a small group of nevi that develop in adolescents and have some particular histopathological features. The pathological diagnosis is difficult as the microscopic features are very similar to a conjunctival melanoma, but a detailed microscopic examination, immunohistochemical stainings and the young age of the patient could help in establishing the benign nature of these lesions.