PMON107 Pineal Germinoma with Pituitary Involvement: Long-Term Survival following Treatment with Whole Ventricular Radiation

INTRODUCTION: Intracranial germinomas usually arise from midline structures such as the pineal gland or suprasellar region. Involvement of both structures occur in 6% of cases. We are reporting long-term follow up of a patient with pineal germinoma with pituitary involvement treated successfully with whole ventricular radiation. CLINICAL CASE: A 36-year-old man presented with polydipsia and polyuria 12 years ago. He also reported fatigue and cold intolerance. Vital signs: BP 130/75 mmHg, HR 69 bpm. Physical examination demonstrated moist mucous membranes and the rest of the examination was unremarkable. Labs: serum albumin 4.9 g/dL, calcium 9.8 mg/dL, glucose 91 mg/dL, potassium 4.2 mEq/L, sodium 145 mEq/L, and serum osmolality 294 mOsm/kg (reference 275-295). The patient also had multiple urinalyses showing a specific gravity of 1.005. Results of a water deprivation test: urine osmolality 114 mOsm/kg (50-1350) at 0805, 87 mOsm/kg at 0858, 73 mOsm/kg at 0955, 80 mOsm/kg at 1045, 88 mOsm/kg at 1150, and 102 mOsm/kg at 1253. His serum antidiuretic hormone during the water deprivation test was <0.8 pg/mL (ref 0.0-4.7). Since these labs suggested central diabetes insipidus, a pituitary MRI was performed that demonstrated two mass lesions in the region of the cephalad portion of the pituitary stalk, hypothalamus, and optic chiasm as well as in the pituitary gland region. Biopsy of the mass lesions was consistent with germinoma. MRI of the spine revealed no evidence of disseminated disease. Additional labs: TSH 1.88 mIU/L, free thyroxine 0.46 ng/dL, IGF-1 62 ng/mL (109-284), prolactin 25 ng/mL, FSH 1.9 mIU/mL, LH 2.5 mIU/mL, total testosterone 183 ng/dL, and cortisol 3.2 ug/dL. An ACTH stimulation test confirmed central adrenal insufficiency. The patient was treated with radiation therapy to the whole ventricles with for a total dose of 45 Gray per cycle. Follow-up MRI in our patient following treatment demonstrated no evidence of persistent or recurrent disease. However, he continues desmopressin for diabetes insipidus and levothyroxine 88 mcg daily for central hypothyroidism whereas the adrenal insufficiency has completely resolved. The patient has been without disease recurrence for the last 12 years and is doing well with a good quality of life. Radiation therapy alone has been highly effective in the management of intracranial germinomas with an overall survival of up to 85%. However, recent studies have shown that chemotherapy followed by lower dose of complete ventricular radiation is as effective as high dose ventricular radiation for local or bifocal germinomas with lower risk of long-term consequences. CONCLUSION: This case illustrates that long-term survival can be achieved in patients with germinomas following appropriate treatments. Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.