MON-513 A Rare Case of Incidentally Discovered Adrenal Neuroblastoma in an Adult

Abstract Disclosure: Z. Goodman: None. A. Morris: None. Background: Adrenal masses in adults are frequently incidental findings, with the majority being benign adenomas. Neuroblastoma, typically a pediatric malignancy, is rare in adults, posing unique diagnostic and therapeutic challenges. Case Presentation: A 30-year-old male presented to the emergency department with right lower quadrant abdominal pain and was incidentally found to have a 5x5 cm right adrenal mass on imaging. Further hormonal workup revealed it as a non-secreting incidentaloma. Dedicated adrenal imaging demonstrated a heterogeneous mass with irregular areas of cystic necrosis and enhancement at 40 HU. The patient underwent endocrine surgical evaluation and unilateral adrenalectomy. Pathology revealed a poorly differentiated neuroblastoma with unfavorable histology and Schwannian stroma-poor features. Pre-operative CT chest revealed no metastasis and post-operative MRI demonstrated indeterminate focal osseous lesions in L1 and S3 vertebrae and a right hepatic lobe lesion. However, post-operative nuclear medicine scan revealed no tumor residual or recurrence. An interdisciplinary tumor board discussed the case with recommendation for pediatric oncology evaluation. Discussion: Neuroblastoma is a common extracranial solid tumor in children but is rare in adults, with distinct differences in biology, behavior, and outcomes. Unlike pediatric cases, where genetic mutations can guide prognosis, the molecular basis of adult neuroblastoma remains unclear, presenting an opportunity for future research. This case revealed Schwannian stroma-poor, poorly differentiated neuroblastoma with unfavorable histology—an aggressive subtype. Notably, the absence of metastases and clear surgical margins are uncommon in adults, who are often diagnosed at advanced stages. This underscores the importance of early detection, even in incidental cases. Referral to pediatric oncology for long-term management highlights the lack of established adult-specific treatment protocols. Pediatric neuroblastoma therapy often involves multimodal regimens. However, adult neuroblastoma often has shown less favorable responses, illustrating the need for tailored strategies and vigilant follow-up. Conclusion: This case provides insights into adult neuroblastoma, emphasizing the importance of interdisciplinary collaboration and early detection. The absence of hormone secretion and incidental presentation showcases its variability. Further research into the molecular and clinical distinctions between pediatric and adult neuroblastoma is essential to develop adult-specific treatment protocols and improve outcomes. Presentation: Monday, July 14, 2025