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while intracranial lesions associated with precocious puberty are either supra-

sellar (astrocytoma) or extrasellar (germinoma, hamartoma) in location. Rarely,

patients with intrasellar craniopharyngioma with suprasellar extension may

also present with precocious puberty. The sellar or sellar–suprasellar mass in

primary hypothyroidism is due to thyro-lactotrope hyperplasia and simulates

pituitary tumor. Therefore, thyroid function test should always be performed in

any patient with precocious puberty as optimal treatment with levothyroxine

not only results in regression of secondary sexual characteristics but also pre-

vents inadvertent pituitary surgery and treatment with GnRH agonist. The index

patient had serum T 4 2.2 μg/dl, TSH 267 μIU/ml, and prolactin 110 ng/ml, and

99mTc thyroid scan showed ectopic thyroid. She was treated with levothyroxine.

After 6 months of therapy, she had regression in breast size and resolution of

sellar–suprasellar mass (Fig. 6.10).

a b

c

Fig. 6.10 (a) A 2-year-old child with primary hypothyroidism presented with breast development
(B 2 ). (b) Coronal CEMR showing homogenous pituitary enlargement with splaying of optic chi-
asma suggestive of thyro-lactotrope hyperplasia. (c) Coronal CEMR showing marked reduction in
the pituitary size after 6 months of L-thyroxine replacement in the same patient

6 Precocious Puberty