26 - OUTCOMES AND HISTOLOGICAL VARIATIONS OF PARANEOPLASTIC SYNDROMES OF NEUROBLASTOMA AND GANGIONEUROBLASTOMA

Objectives: To characterize the pediatric patient tumor profile in which paraneoplastic syndromes may arise. We aim to focus on the histologic subtypes of tumor and their response to treatment.

Neuroblastomas are the most common extracranial solid malignancy in children, with a prevalence of about 1 in 7,000 births. Neuroblastomas primarily develop in the abdomen but can have variable manifestations depending on whether paraneoplastic syndromes are present. Gross total resection of the tumor is the fundamental treatment modality depending on the final staging of the tumor.

Methods: We performed a single institution retrospective cohort study of all patients less than 18 years old diagnosed with neuroblastoma or ganglioneuroblastoma between January 2002 and July 2022. Patients were identified through the pathology and cancer registry and cross-referenced with pediatric records. Patient demographics, clinical presentation, treatment, and outcomes were collected. A univariate descriptive analysis of the collected data was conducted.

Results: In our study period, 130 children were diagnosed with neuroblastoma, and 15 were diagnosed with ganglioneuroblastoma. There were 12 children with a paraneoplastic syndrome identified, 8 with NBL and 4 with GNBL. The average age at diagnosis was 22 months. All but 1 underwent resection prior to treatment of paraneoplastic syndrome, and 4 children required neoadjuvant therapy. Neurological complications were the most common with 10 children (83%). One child had elevated levels of VIP, and one had positive PTH-RP detected. Seven children had complete resolution of their symptoms after treatment and resection, 3 children recently started treatment within a year, 1 had partial resolution, and 1 died during treatment. The average time from symptom onset to diagnosis of neuroblastoma was 0.7 months. The presence of tumor-infiltrating lymphocytes occurred in 4 children with neurologic paraneoplastic syndromes. Six children with paraneoplastic syndromes had neuropil-rich tumors. The characteristics of the 12 patients are shown in Table 1.

Biological features included favorable histology in 6 patients, unfavorable in 4 and unknown in 2 patients. One patient had MYCN amplification. Two patients had 11q mutations.

Conclusion: The histological profile of paraneoplastic syndromes neuroblastoma and gangioneuroblastoma as well as their treatment across the nation can be highly variable. The presence of tumor-infiltrating lymphocytes and neuropil may have an impact on paraneoplastic pathology. Our study is limited in size, and a more extensive multi-institutional study may be needed to elucidate the relationship between the pathology and response to treatment in patients with paraneoplastic syndromes of neuroblastoma.