How big are Growth hormone secreting pituitary tumors? GH-secreting tumors vary considerably in size, but most are > 1 cm in diameter when diagnosed (i.e., macroadenomas), and some can be very large. Tumor size is an important issue because it determines success rates of treatment.
If MRI of the pituitary confirms a tumor in the patient with acromegaly, what issues other than the metabolic effects of excessive GH should be considered? Is the tumor making any other pituitary hormones besides GH? For example, many GH-secreting tumors also produce prolactin; rare tumors also make thyroid-stimulating hormone or other pituitary hormones. In …
Do tumors ever cause acromegaly or gigantism by making excessive GHRH? Yes. Rare cases of GHRH production by various tumors have been described in the lung, gastrointestinal tract, or adrenal glands. They cause acromegaly by stimulating pituitary secretion of GH. The clinical and biochemical features of acromegaly are indistinguishable from those of acromegaly caused by …
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Are other endocrine syndromes possible in patients with acromegaly or gigantism? Yes. Otherwise acromegaly and gigantism would not be endocrine disorders. Three endocrine syndromes include acromegaly Endocrine Syndromes Associated with Acromegaly SYNDROME MAJOR INVOLVED ORGANS CLINICAL FINDINGS OTHER CLUES Multiple endocrine neoplasia type 1 (MEN 1) Pituitary tumorsParathyroid hyperplasiaIslet cell tumors Hypercalcemia (most)Peptic ulcer disease …
Are some Growth hormone producing tumors more aggressive than others, and is there a way to tell? GH-producing tumors causing acromegaly are often characterized histologically as being densely granulated or sparsely granulated. Sparsely granulated GH-producing tumors are less well-differentiated tumors, are generally more locally aggressive, respond less well to somatostatin analogues, and have a worse …
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What causes Growth hormone secreting pituitary tumors? GH-secreting pituitary tumors are monoclonal, indicating that a spontaneous somatic mutation is a key event in neoplastic transformation of somatotrophs. Further studies have clarified the nature of the mutation in some GH tumors that appear to have an altered stimulatory subunit (G S ) of the G-proteins that regulate adenylate …
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After the biochemical diagnosis of acromegaly or gigantism is made, what is the next step? Excessive secretion of GH is almost always caused by a benign pituitary tumor. Therefore, the next step is to obtain a radiologic study of the pituitary gland. The optimal study is magnetic resonance imaging (MRI) with special cuts through the …
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