SAT-253 Long-Term Management and Successful Pregnancy of a Patient with a TSH Secreting Macroadenoma Treated with Octreotide

Introduction: TSH-secreting pituitary adenomas (TSHomas) are the rarest form of pituitary tumors. Transsphenoidal surgery is usually the treatment of choice, although somatostatin analogs (SSAs) are a reasonable and effective option. Pregnancy in the setting of TSHomas is an even rarer situation, scarcely reported in the literature. We report the long-term management of a TSHoma treated with octreotide who developed a successful pregnancy. Case Report: A 16 year-old girl was diagnosed in 2003 with a TSHoma after presenting with goiter, weight loss, tremors and headache. Laboratory tests showed central hyperthyroidism: TSH 2,78 uUI/ml (0,27-4,02); T4 22,4 ng/dl (4,8-12,7); T3 430 ng/dl (72-170) and pituitary MRI showed a 2 cm adenoma. TRH test showed a blunted response, and TSH did not suppress after T3 test, with hormonal values returning to normal range after octreotide administration. Since 2003 the patient have been treated with Octreotide LAR 20 mg. At 34 years-old she expressed her willingness to become pregnant. At this time, hyperthyroidism was controlled (TSH 1.79; T4 12; T3 181) and the pituitary adenoma was smaller (1.2 cm) while on octreotide LAR 20 mg every 8 weeks. Before conceiving, she did a visual field test that was normal and measured α-subunit (αSU), which was slightly increased (0.73 ug/l, upper limit of normal [ULN] < 0.6 ug/l). After 3 months, she successfully conceived. During first trimester, thyroid function remained controlled. The patient was asymptomatic and the fetus was developing as expected. From 18 weeks on, T3 started to increase (T3 227 ng/dl– ULN 200 ng/dl) with normal T4 and FT4 and without symptoms or fetal repercussion. Alpha-subunit increased to 9.5 ug/l. Throughout pregnancy, octreotide was administered in the same pre-pregnancy dosage. At 37 weeks, αSU was 272.314 ug/l after 1:100 dilution (ULN < 604 ug/;) and HCG was 38.316. The patient developed gestational diabetes mellitus that was managed with diet counseling. Spontaneous delivery occurred at 39 weeks, birth weight was 3160g, APGAR 9/10. Newborn thyroid function was normal. Three months after delivery, the patient complained of hand tremors and hair loss. New laboratory tests revealed TSH 6,7 uUI/ml (ULN <4.5); T4 12,9 (ULN <12); T4L 3,3 (ULN <1.7); T3 247 (ULN <200) and αSU was 513 ug/l (ULN< 0.6). Octreotide LAR 20 mg interval was decreased to every 6 weeks. Currently, ten months after delivery, the patients is asymptomatic and thyroid function is normal. Conclusion: TSHoma appears to be safely managed throughout pregnancy without the need of stopping octreotide, which seems not to adversely affect outcomes for the mother and the fetus. This case also illustrates the long-term management (16 years) of TSHoma with octreotide with excellent hormonal and structural response.