Twisted Ovarian Cyst, Galactorrhea and Pituitary Hyperplasia Misdiagnosed as Prolactinoma: An Overlooked Longstanding Overt Hypothyroidism from Hashimoto’s Thyroiditis

Abstract

We describe a 14-year-old girl who was referred for management of a prolactin-secreting pituitary adenoma as she had persistent milky discharge from her nipples, an elevated prolactin level and pituitary enlargement. Upon reviewing the medical history, it was noted that she had a history of secondary amenorrhea for 1 year, and had undergone an oophorectomy for twisted left ovarian cyst 5 months earlier. The physical examination found that she had a goiter, short stature and was relatively overweight. Based on these findings, it was thought that the patient likely had longstanding overt hypothyroidism. A thyroid function test (TFT) revealed a free thyroxine (FT4) level of 0.2 ng/dL and thyroid stimulating hormone (TSH) >100 mU/L, with high levels of antithyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-TG) antibodies, leading to the diagnosis of Hashimoto’s thyroiditis. After 8 months of levothyroxine treatment, the galactorrhea had disappeared, the pituitary enlargement had resolved and her menstruation had resumed normally, along with a 4-kg weight loss and 3-cm height gain. In summary, when evaluating a girl with ovarian cyst(s), especially if accompanied by other clinical findings like goiter, short stature, or menstrual irregularities, the physician should include hypothyroidism in the differential diagnosis. Early diagnosis and treatment of hypothyroidism can have a positive impact on the overall health and well-being of these patients, potentially preventing further complications related to both the thyroid disorder and ovarian cyst(s).