The Deceptive Neurofibroma: A Case Report

Abstract

Introduction Melanoma, a significant dermatological malignancy, presents in diverse forms, including orbital involvement, with both primary and secondary manifestations posing diagnostic challenges [1]. Metastatic orbital melanoma accounts for 5–20% of cases [2], presenting with diplopia, ptosis, and optic nerve compression [3,4]. Diagnosis involves specific staining (e.g., S100, HMB-45, Melan-A) [4], with treatment relying on surgery and radiotherapy [5]. Prognosis remains poor, with a median survival of 36.9 months [6]. Neurofibromas, though rare (2–4% of orbital tumors), arise from nerve sheaths and often test positive for S100 in immunohistochemistry. They may undergo malignant transformation, particularly in neurofibromatosis (NF1) patients [7,8]. This report highlights the coexistence of orbital melanoma and neurofibroma, showcasing diagnostic and therapeutic complexities. Case Presentation A 57-year-old female presented with a non-healing left lower eyelid nodule. Diagnosed with melanoma in 2017, she underwent eight surgeries and radiotherapy over six years. Initial biopsy confirmed malignant melanoma (S100, Melan-A, HMB-45 positive). Subsequent biopsies revealed recurring neuromas and, later, a neurofibroma diagnosis in 2023. MRI scans documented tumor progression, including lesions infiltrating the orbit. Despite interventions, including eyelid reconstructions and radiation therapy, the tumor persisted. A multidisciplinary review suggested NF1, confirmed by biopsy. Discussion Melanoma and neurofibroma overlap histopathologically, complicating diagnosis. Both express S100 and SOX-10 but lack Melan-A and HMB-45. CD34 can distinguish neurofibromas (96% positivity) from desmoplastic melanomas (4%) [9-12]. PRAME and P53 markers favor DM diagnosis, but neurofilament staining lacks specificity [13-15]. NF1 patients face elevated melanoma risk due to NF1 gene mutations (17q11.2), underscoring the need for vigilance [16]. Conclusions The overlapping features of melanoma and neurofibroma, particularly in NF1, require a multidisciplinary approach for accurate diagnosis and management.