Ectopic secretion of growth hormone-releasing hormone in man

Pathophysiology and clinical aspects of the ectopic GH‐releasing hormone syndrome

“…It should be noted that production and even secretion of GHRH from human tumours has been described in some patients without clinical and biochemical evidence of active acromegaly (Losa et al, 1990(Losa et al, , 1993. Thus, unequivocal demonstration of active acromegaly is mandatory for a correct definition of acromegaly due to ectopic secretion of GHRH.…”

“…About 40 cases of ectopic GHRH syndrome have been reported in the world literature in the last 20 years (Sano et al, 1988;Faglia et al, 1992;Losa et al, 1993), to which another dozen patients with suspected but not firmly established ectopic secretion of GHRH might be added. Even though ectopic GHRH syndrome seems to account for a very 124 M. Losa and K. von Werder ᭧ 1997 Blackwell Science Ltd, Clinical Endocrinology, 47, 123-135 small fraction of all cases of acromegaly, undereporting or, more likely, unawareness of the diagnosis might lead to an underestimation of the syndrome.…”

“…Large acini of GH-secreting cells are intermingled with a few normal adenohypophysial cells, especially lactotrophs. While these cells might represent trapped normal lactotrophs, their abundance and the clinical observation of a high frequency of hyperprolactinaemia in patients with the ectopic GHRH syndrome (Losa et al, 1993) raise the possibility that chronic exposure to GHRH may also stimulate lactotroph growth. In fact, it has been demonstrated that normal subjects show a rise in PRL after the intravenous administration of larger doses (600 mg) of GHRH (Sassolas et al, 1984).…”

“…Carcinoids, especially of the lung and the gastrointestinal tract, are the most frequent tumour type in patients with the ectopic GHRH syndrome, constituting about two-thirds of all cases reported so far, followed by islet cell tumours (Faglia et al, 1992;Losa et al, 1993). Among the other tumour types associated with ectopic acromegaly are a phaeochromocytoma (Roth et al, 1986), a retroperitoneal paraganglioma (von Gottschalk et al, 1986) and a lung cystic adenocarcinoma (Southgate et al, 1988).…”

An unusual cause of acromegaly

“…In contrast to patients with classical acromegaly, no pituitary tumour but an enlargement of the sella is detected in the majority of such patients. 12 The first MRI of the pituitary gland in our patient suggested the presence of an anterior pituitary macroadenoma, which is unexpected in patients with GHRH-secreting bronchial carcinoid. Thus, three other issues need to be considered.…”