肢端肥大症(acromegaly) 是一罕見疾病，特徵是器官不正常的增生或肥大，尤其在四肢和顏面。過量生長素(growth hormone, GH) 的分泌，在青春期之前，因骨骺尚未閉合，因此會引起巨人症(gigantism)；而在青春期之後，則會導致肢端肥大症。生長素分泌過多的病程通常是緩慢的，其會逐漸影響代謝功能和生長發育。診斷標準包括了臨床症狀、生化檢驗和影像發現。生化檢驗主要是生長素的濃度無法被葡萄糖所抑制( 生長素的濃度仍然>1 ng/mL) 或類胰島素生長因子-1 (insulin-like growth factor 1, IGF-1) 超過正常值。治療原則主要是減少生長素和 IGF-1 的分泌，如果病人罹患垂體腫瘤，則經蝶竇垂體腺瘤切除術(trans-sphenoid pituitary adenomectomy) 應是治療的首選，以減少腫瘤的大小與分泌。如果科手術無法將生長素和 IGF-1 的濃度減至正常，則可考慮內科療法，治療藥物主要是體抑素類似物(somatostatin analogues) 或合併放射治療。使用體抑素類似物出現明顯的抗性或副作用
時，則可考慮使用生長素受體拮抗劑(growth hormone receptor antagonist)。近年來，肢端肥大症的病人在免疫系統、心血管系統、呼吸系統和代謝方面的預後，已有明顯改善。

Acromegaly is a rare disease characterized by exaggerated somatic growth, especially involving the extremities and face, that is associated with systemic manifestations related to organ overgrowth. High exposure to growth hormone produces gigantism in youths prior to epiphyseal fusion and acromegaly in adults. Effects of hypersomatotrophism is characterized by slowly progressive acquired somatic disfigurement(mainly involving the acral and soft tissue growth)and metabolic function. The diagnostic criteria include clinical presentations, biochemical profiles and image findings. The laboratory data requires GH concentration unsuppressible by an oral glucose load (>1.0 ng/mL) or by detection of increased levels of insulin-like growth factor-I (IGF-I). A comprehensive strategy
for treatment is aimed at management of the pituitary mass, and at reducing GH and IGF-I hypersecretion. Transsphenoidal surgery is generally the first-line treatment. If surgery fails to correct GH/IGF-I levels to normal values,medical treatment with somatostatin analogues and/or radiotherapy can be tried. The GH-receptor antagonist
(pegvisomant)is used in patients with resistance to or intolerance of somatostatin analogues. The prognosis has improved in the recent years; it is definitive by rheumatologic, cardiovascular, respiratory and metabolic consequences.