Cushing's Disease in a Patient With an Ectopic Pituitary Adenoma

Juxtaposition of an ectopic corticotroph adenoma of the sphenoid sinus with orthotopic intrasellar corticotroph hyperplasia in a patient with Cushing disease

“…Presence of such vascular connections has been offered previously as an explanation of ongoing pituitary function, despite ostensibly complete hypophysectomy, because ectopic pituitary tissue may remain a functional part of the hypothalamic-adenohypophysial system, by virtue of transsphenoidal vascular connections. 9,11,26,46 The ability of the tumor to secrete CRH and the presence of the means to transport and distribute this CRH to the pituitary gland seem to be the minimum requirements for the coexistence of pituitary hyperplasia and an ACTH-positive adenoma according to the present theory. Thus, the rarity of a typical intrapituitary ACTH-secreting adenoma associated with pituitary hyperplasia in the rest of the gland may be due, in part, to the lack of excretion of both CRH and ACTH by the tumor cells and, in part, because of the arrangement of the hypophyseal portal system, which does not allow the product of the pituitary cells to circulate within the gland but rather to be carried away to the systemic circulation.…”

“…), ectopic adenoma has been confirmed in only two: this case and one other reported by Coiré, et al 9 The first reported case of EPA was described by Erdheim in 1909; 14 since then approximately 50 cases have been reported, including the present one. [1][2][3][6][7][8][9]11,13,[15][16][17][18][19][20][22][23][24][25][26][27][28][29][30][31][32][33][34][35]37,[39][40][41][44][45][46][47][48][49][50][51][52][53][54][56][57][58] The rarity of EPA, despite the frequent presence of ectopic embryonic remnants of the pituitary gland, is intriguing. It is possible that many EPAs are both...…”

Glucocorticoid responsive ACTH secreting bronchial carcinoid tumours contain high concentrations of glucocorticoid receptors

“…Following bilateral adrenalectomy, plasma ACTH levels rose progressively to levels normally seen in Nelson's syndrome. For this reason, a pituitary remnant or parapituitary (Schteingart et al, 1987;Kammer & George, 1981) source ofACTH had to be considered seriously until the pulmonary lesion was finally recognized 6 years later. One previously reported case (Lalau et al, 1990), initially diagnosed after surgical adrenalectomy as Nelson's syndrome (on account of abnormal pituitary anatomy and massive ACTH elevation), was eventually found to have an ACTH secreting bronchial carcinoid tumour 20 years later.…”

Ectopic pituitary adenoma in the sphenoid sinus causing acromegaly associated with empty sella

“…An ectopic pituitary adenoma arising in the sphenoid sinus is a rare clinical entity. Only 23 reports of ectopic pituitary adenomas arising in the sphenoid sinus have been found in the literature 1–23 . Moreover, an ectopic pituitary adenoma arising in the sphenoid sinus associated with empty sella is extremely rare and only four such cases were reported previously 11,14,15,17 .…”