SUN-288 Atypical Teratoid Rhabdoid Tumor of the Sellar Region: An Unusual Cause of Hypopituitarism

Background: Atypical teratoid/rhabdoid (AT/RT) tumor of the sellar region is an extremely rare malignant tumor in adults. To date, there are no definitive guidelines for optimal treatment and the prognosis of this tumor is poor. The pituitary insufficiency was rarely mentioned in previous literature and might be overlooked. Clinical case: A 43 years old female presented to our clinic with severe periorbital pain. The magnetic resonance imaging of the brain revealed a 1.5x1.5x 3 cm sellar mass which showed inhomogeneous enhancement after gadolinium administration. Hormonal work up showed 8AM cortisol of 1.86 mcg/dL, free T4 1.0 (0.8–1.8 ng/dL), TSH 0.05 (0.3 - 4.1 uIU/ml), FSH 6.0 (1.6–9.3 IU/L), LH 1.8 (2.4–9.3 IU/L), estradiol <18.35 (80–790 pmole/L), IGF-1 96.6 (50.6–263.7 ng/ml), prolactin 56.6 ng/ml. She underwent transsphenoidal surgery with tumor removal. The pathological result showed a mixture of pleomorphic spindle cell, oval shape tumor and poorly differentiated cell. The tumor was negative for INI1 (SMARCB1) compatible with AT/RT WHO grade IV. She developed pan hypopituitarism after surgery. She received 6 courses of 5950 cGy/25 fractions cranial irradiation and 6 courses of ifosfamide, cisplatin and etoposide. She completed the treatment regimen without significant toxicity. She continued hormonal replacement for panhypopituitarism and is still being followed at our clinic for 4 years without tumor progression or other complications. In previously reported cases, all of the sellar AT/RT were female with a median age of 45 years old (range 20–61). The clinical presentations are rapidly enlarged sellar mass with compressive symptoms to the adjacent structures. The radiological findings of sellar AT/RT are non-specific. The diagnosis is based on histopathological findings. Presence of rhabdoid cells on histopathology and polyphenotypic immunopositivity for epithelial, mesenchymal, and neuroectodermal markers along with loss of expression of SMARCB1/INI1 help in establishing a diagnosis of AT/RT. Currently, there are no definitive guidelines for optimal treatment. Multimodality treatment consisted of surgery, radiation and chemotherapy are the mainstays of treatment of the AT/RT. Of the 16 adults reported in the literature, 9 patients survived more than 12 months resulted in 47% of one-year survival rate. To our knowledge, this case is the sellar AT/RT with the longest survival to date. Conclusion: AT/RT is one of the most aggressive tumors in the sellar area. Due to its aggressiveness, hypopituitarism is anticipated. Our patient had postoperative secondary adrenal insufficiency, secondary hypothyroid and hypogonadotropic hypogonadism. Apart from multimodality treatment required for tumor control, pituitary hormones should be evaluated preoperatively to prevent perioperative mortality and long-term improvement in the quality of life.