MON-262 A Case of the Suprasellar Atypical Teratoid Rhabdoid Tumor (ATRT) Presenting in an Adult Treated with Intrathecal Chemotherapy

Background: Atypical teratoid rhabdoid tumors (ATRTs) are highly malignant tumors that usually present as a posterior fossa mass in children less than 3 years old. Only 38 cases have been reported in adults. They are also typically located in the supratentorial region. In none of the reported cases of suprasellar ATRT in the adult, intrathecal chemotherapy (via ommaya) has been used. Clinical case: A 70-year-old woman presented with a severe headache and magnetic resonance imaging (MRI) revealed a suprasellar mass measuring 2.9 x 2.1 x 3.0 cm. Shortly after her presentation, she developed an acute 3rd nerve palsy, and repeat MRI found dramatic interval growth. A transsphenoidal approach for biopsy/resection was attempted, but the lesion was not accessible via this corridor. She then underwent a right frontotemporal craniotomy and subsequently developed panhypopituitarism, including diabetes insipidus. Pathology revealed poorly differentiated malignant cells. Immunohistochemistry was positive for synaptophysin, Epithelial Membrane Antigen (EMA), Tumor protein p53, and negative for integrase interactor 1 (INI-1 antibody) with loss of expression in tumor nuclei with positive internal control in endothelial cells. These findings confirmed the diagnosis of ATRT. The Ki-67 index was 60% consistent with a highly proliferative tumor. One month later, she developed acute mental status change. Repeat computed tomography, and MRI showed recurrence of the tumor at the same location with new leptomeningeal enhancement involving the left facial nerve. Multimodal treatment was instituted, consisting of intraventricular/intrathecal chemotherapy with etoposide and topotecan plus fractionated external beam cranial irradiation (30 Gy in 10 fractions). She continued to deteriorate, and following consultation with her family, she was transferred to hospice care and died six months following her initial surgery. Conclusion: This is the first case of adult suprasellar ATRT that has been treated with intrathecal chemotherapy. There is no consensus on the best combination of chemotherapy, and often the St. Jude’s protocol used in the treatment of pediatric ATRT is used. In line with the biological behavior reported for this tumor in children and adults in different locations, the tumor was very aggressive, resulting in the patient’s death only after 6 months from the diagnosis despite aggressive surgical and medical treatment. Reference: 1. Athale, U. H., J. Duckworth, I. Odame, and R. Barr. 2009. Childhood atypical teratoid rhabdoid tumor of the central nervous system: a meta‐analysis of observational studies. J. Pediatr. Hematol. Oncol. 31:651-663. 2. Shonka N, Armstrong T (2011) Atypical teratoid/rhabdoid tumors in adults: A case report and treatment-focused review. J Clin Med Res 3: 85-92.