Ectopic prolactinomas and somatotropinomas

Abstract

Introduction Ectopic pituitary tumors (EPT) are very rare comparing to eutopic ones. Their mechanism is still debated. Our aim was to report 10 cases observed in our practice. Cases series Six prolactinomas and 4 somatotropinomas were collected. They were located in the suprasellar area for 3: two prolactinomas and one somatotropinoma, in the clivus for 3: 2 prolactinomas and one somatotropinoma, or in the sphenoid sinus n = 4: 2 prolactinomas and 2 somatotropinomas. For the infrasellar lesions, the diagnosis was relatively easy as the tumors were visible in infrasellar position and were associated to an empty sellar suggesting an inhibition of the pituitary gland by an ectopic hormonal secretion. Regarding suprasellar lesions, the 3 tumors invaded the pituitary area. The diagnosis was made in retrospect after tumor shrinkage due to medical treatment. Actually, MRI done after dopamine agonists or somatostatin analogues showed a quick disappearance of the intrasellar part of the tumor first, and then it was the suprasellar part turn. After the last control, only a very small residual tumor was visible in the suprasellar area. On the therapeutic point, we remarked that inhibition of prolactin and growth hormone secretion was similar in both positions; however tumor shrinkage was better in suprasellar tumors. Conclusion Those 10 unusual cases should be known for their rarity, their unknown physiopathology and their response to medical treatment.