Adenoma of the Thyreoid.—In this condition the swelling of the thyreoid is due to the growth within its substance of one or more adenomas of variable size and surrounded by a capsule. The rest of the gland may be normal, or may show some degree of hyperplasia. Some are solid, others undergo cystic degeneration, the glandular tissue being replaced by a quantity of clear or yellowish fluid, sometimes mixed with blood. The cysts thus formed may be unilocular or multilocular, and intra-cystic papillary vegetations frequently grow from their walls. The walls of the cysts may be thin, soft, and flaccid, or thick and firm, or they may even be calcified.
The thyreoid is enlarged, but instead of the uniform enlargement which characterises the parenchymatous goitre, it tends to be uneven, with hillocky projections corresponding to the individual cysts ([Fig. 280]), and in these fluctuation may be detected. It is to be noted that there are no toxic symptoms in cystic adenoma.
Fig. 280.—Multiple Adenomata of Thyreoid in a woman æt. 50.
(Mr. D. M. Greig's case.)
Fig. 281.—Cyst of Left Lobe of Thyreoid.
(Mr. D. M. Greig's case.)
The treatment is necessarily operative; cystic tumours may be tapped and injected with iodine, but the more satisfactory procedure, both with the solid and cystic forms, is to incise freely the overlying thyreoid tissue and enucleate the tumour.
Malignant Disease of the Thyreoid.—This, whether in the form of carcinoma or sarcoma, usually develops in a gland that has been the seat of goitre for several years, although it may begin in a previously healthy gland.