An unusual case of acromegaly
Wojciech Zieleniewski, Renata Michalak & Agnieszka Jagodzinska
Acromegaly is a chronic disease with typical clinical signs evoked by overproduction of growth hormone (GH) and insulin-like factor 1 (IGF1). It is nearly always caused by somatotroph adenoma which can be visualized by MRI scanning. Other causes of acromegaly are very rare and comprises ectopic secretion of GH or GH-RH by other neoplasms.
Here, we present a case of 62-year old acromegalic woman. Acromegaly was firstly diagnosed 9 years ago. Her GH concentration was 77.6 ng/ml (N: 010) and IGF-1 level 1446.9 ng/ml (N: 81225). Surprisingly, MRI scan of the sellar region (repeated several times) revealed slightly enlarged pituitary, but without any signs of adenoma.
Moreover, chest X-ray showed mediastinal tumor about 5 cm of diameter, confirmed by a CT scan. The patient refused bronchoscopy or other diagnostic procedures of the tumor. We performed a test with short-acting octreotide (100 mcg) which efficiently decreased GH concentration: 0122.0 ng/ml, and after 2 h 2.2 ng/ml. Therefore a prolonged treatment with long-acting octreotide (30 mg each 4 weeks). The treatment is well tolerated with GH concentration 3.67 ng/ml and IGF-1 level 448 ng/ml.
Unfortunately we were unable to measure GH-RH level.
In conclusion we strongly believe that this case of acromegaly is due to benign mediastinal tumor (no progression was noticed) producing ectopically GH-RH or GH.