Pediatric pituitary adenoma with mixed FSH and TSH immunostaining and FSH hypersecretion in a 6 year-old girl with precocious puberty: case report and multidisciplinary management

Objective: We describe a rare case of functioning gonadotropins-producing pediatric adenoma immunostaining positively for FSH and focally for TSH causing central precocious puberty associated to central hypothyroidism in a 6 year-old girl. Materials and Methods: Clinical evaluation revealed precocious puberty, as confirmed by hormonal determination with elevated FSH and estradiol, while central hypothyroidism was biochemically diagnosed by a low fT4 and normal TSH. Head MRI showed the presence of a hyperintense pituitary lesion. The patient successfully underwent transsphenoidal endoscopic resection of the pituitary macroadenoma. Results: Pathologic evaluation of the tissue resected at surgery confirmed the diagnosis of pituitary adenoma with positive immunohistochemistry for FSH and focally for TSH in a mixed pattern. Ten months after surgery, there were no neurological signs and symptoms. Postoperative head MRI showed no abnormalities and no evidence of tumor regrowth. Conclusions: Early and accurate diagnosis, multidisciplinary approach and close follow up are crucial factors for the favorable outcome. © 2020 Informa UK Limited, trading as Taylor & Francis Group.