374 THE DUCTLESS GLANDS 



give rise to acromegaly. Several authors report cases of 

 pituitary sarcoma without any signs of acromegaly. The 

 same applies to carcinoma and endothelioma. 



Microscopical examination shows that the tumour in acro- 

 megaly has all the characters of the anterior lobe of the pituitary 

 body. The various kinds of cells found in the latter structure 

 are also regularly found in the tumour. 



Thus, it would appear that an adenoma of the anterior 

 lobe of the pituitary is the essential lesion characteristic of 

 acromegaly. 



(6) Pathogeny 



Various theories have been sustained as to the origin and 

 essential cause of the symptoms of typical acromegaly. It 

 was suggested by Freund that acromegaly is simply an anomaly 

 of development. Some writers have imagined that the essen- 

 tial lesions in acromegaly are in the thyroid or in the thymus. 

 It has also been suggested that defects in the reproductive 

 organs may be responsible for the conditions (vide infra, p. 375). 

 The nervous system has from time to time been called in 

 question. But of late years most of the theories advanced 

 have assumed that the pituitary is in some way affected in all 

 undoubted cases of acromegaly. 



Of the pituitary theories, the first was that of the original 

 describer of the disease Marie. His view was that acro- 

 megaly is due to destruction of the pituitary, and therefore to 

 complete abolition of its function. Those who still uphold this 

 view look upon the gland as supplying a hormone which 

 regulates the growth of the skeleton, which growth, in the 

 absence of such regulation, proceeds abnormally. Bleibtreu 

 has published a record of a case of acromegaly, in which 

 he states that there was total destruction of the pituitary 

 gland. 



The opposite view, that the symptoms of acromegaly are 

 due to a hypertrophic condition of the pituitary, more particu- 

 larly of its anterior lobe, is held by Tamburini and Woods- 

 Hutchinson. The most important argument in favour of this 

 view is the frequency with which a true adenoma has been 

 reported as occurring in typical cases of acromegaly. It may 

 be supposed that, according to this theory, the anterior lol 



