TSH pituitary adenomas represent less than 1% of operated pituitary adenomas. More then 200 cases have been described till now and more patients are now identified since the widespread of ultrasensitive TSH assay which can detect paradoxical situations of elevated serum thyroxine levels with detectable TSH levels. Differential diagnosis must be done with pituitary resistance to thyroid hormones, disorder in which there is a state of "TSH mediated hyperthyroidism". Transsphenoidal surgery remains the treatment of choice of TSH secreting adenoma. A medical treatment with octreotide can improve biological findings and induce tumor shrinking. We report in this paper a TSH pituitary adenoma in a young girl of 15 years old.