278 



DAVID MARINE 



Fig. 13. Simple marked active hy- 

 perplasia, thyroid of sheep, marked In- 

 foldings and plications, very high 

 columnar epithelium. (After Marine, 

 Johns Hopkins Hosp. Bull., 1907: 18.) 



Secondary Hyperplasias. Developmental Stage. Secondary hyper- 

 plasias or active hyperplasias developing from the colloid or resting 



thyroid are illustrated clinically in 

 the so-called secondary exophthalmic 

 goiters, the thyroid enlargements de- 

 veloping in succeeding pregnancies, or 

 finally in any thyroid which has under- 

 gone hyperplasia and involution more 

 than once. Active hyperplasias de- 

 veloping from colloid glands' are not 

 essentially different from those de- 

 veloping from normal glands. Their 

 interpretation offers more difficulties 

 on account of the wider range of possi- 

 ble morphological changes and a more 

 complicated life history. Thus it is 

 unusual to find secondary hyperplasia 

 uniform throughout a gland while with 

 primary hyperplasias this is the rule. 

 The reason for this lies in the fact that 

 the thyroid is so frequently the seat of degenerative changes, hemorrhage, 

 cyst formation, and so readily modified by trauma, by treatment, preg- 

 nancy, locality, intercurrent diseases, 

 food, etc. Marine and Lenhart (d). 



The important anatomical changes 

 are, however, similar to those occur- 

 ring in the primary hyperplasias and 

 are found in the blood vessels, the 

 colloid, the epithelium and the stroma. 

 The blood supply is increased. The 

 stainable colloid is lessened, but slightly 

 in the milder degrees, while it may 

 be entirely absent in the marked de- 

 grees of hyperplasia. The epithelium 

 changes from cuboidal to high cu- 

 boidal and finally to high columnar. 

 These changes are not uniform through- 

 out the gland and much confusion has 

 arisen on this account. The hyper- 

 plasia is markedly influenced by the 

 blood supply. The blood supply, as a 

 rule, is best preserved in the subcapsular zone, and it is in this zone that 

 the most marked hyperplastic changes are seen. Frequently one sees 

 large central areas, or it may be but a few alveoli that fail to join in the 





Fig. 14. Active hyperplasia, thy- 

 roid of man, illustrating the irregular 

 size and distortion of the alveoli, re- 

 duced colloid, high columnar epi- 

 thelium and increase in stroma. 

 (After Marine, Johns Hopkins Hosp. 

 Bull., 1907: 18.) 



