[TSH secreting adenoma of pituitary gland (TSHom) - rare cause of hyperthyroidism in pregnancy]. / TSH-sezernierendes Hypophysenadenom (TSHom) - seltene Ursache einer Hyperthyreose in der Schwangerschaft.

HISTORY AND ADMISSION FINDINGS: A 28 year-old woman in her first pregnancy was referred to the department of obstetrics and gynecology at 24 weeks of gestation because of pregnancy-induced hypertension. INVESTIGATIONS: Thyroid stimulating hormone (TSH), free T3 and free T4 were elevated. Antibody screening did not show antithyroid peroxidase (anti-TPO) antibodies and TSH receptor antibodies. Clinical findings were suspicious of TSH secreting pituitary tumour (TSH-om) or thyroid hormone resistance (RTH). In absence of clinical sings of elevated intracranial pressure magnetic resonance imaging (MR) was discussed but not carried out and planned after delivery. A visual-field defect was ruled out by orbital field evaluation. TREATMENT AND COURSE: Treatment with 3 × 50 mg propylthiouracil daily was initiated. However, normal fT3/fT4 titers could not be achieved. Serum levels were in the high normal ranges and TSH remained increased. The clinical situation of the patient improved resulting in a normal delivery at term. The healthy newborn was breast feed and MR imaging of the mother revealed a 5×8 mm tumor of the pituitary gland. CONCLUSION: In pregnant women with pregnancy-induced hypertension thyroid diseases have to be ruled out. Rare causes of hyperthyreoidism are TSH secreting pituitary tumors or thyroid hormone resistance (RTH). Treatment of choice for hyperthyreoidism in pregnancy is propylthiouracil. Normal vaginal delivery and breast feeding are possible. Following delivery it is mandatory to determine an individual treatment strategy.