February 26, 2025

A 32-year-old man complains of frontal headache, weight gain, and cold intolerance

By Med-Challenger · 2 minute read

A 32-year-old man with no previous medical history complains of frontal headache for 3 months, unintentional weight gain of 10 pounds, and cold intolerance. On examination, his blood pressure is 120/60 mm Hg and his pulse is 60 beats/minute. His thyroid is not enlarged. His thyroid-stimulating hormone (TSH) level is 464 mIU/L (normal range, 2.5-4.0 mIU/L), free thyroxine (T4) is 0.1 ng/dL (normal range, 0.7-1.9 ng/dlL), and free triiodothyronine (T3) is 75 pg/dL (normal range, 230-619 pg/dL).

Magnetic resonance imaging of the brain shows a sellar mass extending into the suprasellar cistern with mild compression of the optic chiasm (see Figure).

image (90)

Figure. Reproduced from Franceschi R, Rozzanigo U, Failo R, Bellizzi M, Di Palma A. Pituitary hyperplasia secondary to acquired hypothyroidism: case report. Ital J Pediatr. 2011;37:15.

What is the likely cause of this patient’s sellar mass?

nonsecreting pituitary adenoma
primary hypothyroidism
hypothalamic lesions
TSH-producing adenoma

The correct answer is:

primary hypothyroidism

Educational Objective:

Recognize the presentation of pituitary hyperplasia.

Key Point:

Pituitary hyperplasia may simulate a sellar tumor. Primary hypothyroidism can cause a sellar mass from overproduction of thyrotropin-releasing hormone. The hormonal profile will show a high TSH level and a low T3 and T4 value.

Explanation:

The patient’s hormonal profile is suggestive of primary hypothyroidism. Lack of production of T3 and T4 causes, by negative biofeedback, and increase of the thyrotropin-releasing hormone in turn causes hyperplasia of the hypophysis.

The patient does not have a pituitary tumor; rather, he has diffuse hyperplasia of the hypophysis as a consequence of thyrotropin-releasing hormone stimuli.

A TSH-producing adenoma is associated with high, not low free T3 and T4 levels.

A patient with a hypothalamic lesion will not have a sellar mass.

A nonsecreting adenoma may cause symptoms from compression and potentially secondary hypothyroidism, but, in such a case,,, the TSH level would be low, along with low T3 and T4 levels

References:

Neves CP, Massolt ET, Peeters RP, Neggers SJ, de Herder WW. Pituitary hyperplasia: an uncommon presentation of a common disease. Endocrinol Diabetes Metab Case Rep. 2015;2015:150056.

Passeri E, Tufano A, Locatelli M, Lania AG, Ambrosi B, Corbetta S. Large pituitary hyperplasia in severe primary hypothyroidism. J Clin Endocrinol Metab. 2011;96(1):22-23.

This question appears in Med-Challenger Internal Medicine Exam Review with CME

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