SAT-LB304 A Rare Case of Atypical Teratoid/Rhabdoid Tumor of Sellar Region in an Adult

Introduction: Atypical teratoid/rhabdoid tumor(ATRT) is an aggressive tumor of the central nervous system mostly seen in the pediatric age group. It is rare for these tumors to occur in adults, especially in the sellar region. Here we describe a case of ATRT of sellar region with rapidly progressive confusion and panhypopituitarism. Case report: 58-year-old Caucasian woman presented with complaints of headache, generalized weakness, nausea and anorexia. Patient was also noted to be confused throughout her presentation and unable to provide detailed history. She also complained of blurring of vision and was noted to have visual field loss by her ophthalmologist. CT head without contrast revealed a sellar mass with suprasellar extension which is 2.5 x 2.4 x 3.5 cm with mass-effect on the base of anterior third ventricle. Blood work showed an A.M cortisol of 0.2 mcg/dL(6.2-19.4), prolactin of 62.6 ng/mL(4.8-22.3), TSH of 2 mIU/L(0.27-4.20) and free T4 of 0.36 ng/dL [0.80-1.90]. Cosyntropin stimulation test showed a 30-minute cortisol of 2.8 mcg/dL and a 60-minute cortisol of 4 mcg/dL. She was also noted to have hypernatremia with serum sodium upto 151 mmol/L(136-145). She was started on levothyroxine 88 mcg, DDAVP 0.1 mg PO twice daily and stress dose steroids which was weaned down to prednisone 7.5 mg daily eventually. MRI revealed 2.1 cm sellar mass with 3.1 cm suprasellar extension and rapidly progressive increase in size over several weeks period. Patient initially underwent left frontal midline craniotomy via transcallosal approach for resection of third ventricular and supra sellar tumor. For the residual tumor removal, she also underwent endoscopic resection of ATRT of brain via extended transnasal craniotomy with extensive nasoseptal flap repair of the skull base. Pathology revealed atypical teratoid/rhabdoid tumor of sellar region, WHO grade IV. The neoplastic cells characteristically show loss of INI-1 (SMARCB1), retained BRG1 (SMARCA4), focal weak positivity for EMA, Vimentin, Neurofilament (NF), CD56 and Cytokeratin AE1/AE3 is strongly positive. There is patchy non-specific immunoreactivity to PAX5 and PAX8. Hospital course was complicated by respiratory failure, NSTEMI, encephalopathy and patient is currently receiving supportive care for the same. Patient will be receiving radiotherapy and chemotherapy for further management of ATRT. Conclusion:This case represents a rare occurrence of ATRT and suggests the need for suspicion in case of rapidly growing pituitary mass with progressive panhypopititarism.