Introduction Pituitary hyperplasia secondary to primary hypothyroidism (PHPH) is a rare condition caused by untreated hypothyroidism, leading to thyrotroph cell proliferation and pituitary enlargement. Common manifestations include growth disorders, obesity, and hormonal imbalances. PHPH may also present with headaches due to pituitary mass effects, though this is less frequently reported. Despite iodine fortification programs, subclinical hypothyroidism remains prevalent in certain regions. PHPH is often misdiagnosed as pituitary adenoma, emphasizing the need for clinical awareness, particularly in adolescents with atypical symptoms like headaches without classic hypothyroid features. Case Presentation A 16-year-old female presented with severe, medication-resistant headaches, photophobia, and nausea. MRI revealed pituitary enlargement (12 × 11 × 9 mm) and a Rathke cleft cyst. Laboratory tests confirmed severe primary hypothyroidism (TSH: 117 mIU/L, FT4: 0.34 mIU/L) and thyroid atrophy on ultrasound. Levothyroxine therapy normalized TSH (2.6 mIU/L) and FT4 (1.26 mIU/L) within three months, resolving galactorrhea and improving headaches. Discontinuing treatment led to headache recurrence and elevated thyroid peroxidase antibodies (488 IU/mL), confirming autoimmune thyroiditis as the underlying cause. Reinitiating levothyroxine resolved symptoms, underscoring PHPH’s role in her presentation. Conclusion This case highlights PHPH as a rare cause of secondary headaches in adolescents, even without classic hypothyroid symptoms like menstrual irregularities. Timely diagnosis via MRI and thyroid function testing is critical to avoid mismanagement. Levothyroxine effectively reverses pituitary hyperplasia and alleviates symptoms, but long-term adherence is essential to prevent relapse. Clinicians should consider endocrine etiologies in unexplained headaches, particularly in cases resistant to conventional therapies, to ensure prompt intervention and improved outcomes.
Al-Bitar et al. (Sat,) studied this question.