—The cystomas of the ovarian region assume two types: (1) Glandular cystoma, and (2) papillary cystoma.
1. Glandular Cystoma.
—The glandular type produces the multilocular forms, with numerous small and large cavities, filled with fluid which varies in color and appearance within wide limits, having usually the consistency of mucus or thin pus, and containing a small number of cylindrical epithelial cells. The cyst wall may contain tubular glandlike structures reaching into the surrounding connective tissue.
2. Papillary Cystoma.
—The papillary type presents projections into cavities of papillomatous outgrowths from their walls, which are covered by cylindrical epithelium, which latter also lines the cavities. It is most common in the parovarium.
It is rare to find a pure type of either variety; both forms are usually blended. Malignant transformation, of the latter type especially, occurs easily and insidiously, and explains many disappointments in result.
Adenoma and Fibro-adenoma.
—Adenoma is a tumor whose type is the normal secreting gland, from which it differs in being an abnormal outgrowth or product, but particularly in that it has no power of producing the secretion peculiar to the gland tissue or type from which it grows. The adenomas occur for the most part as circumscribed tumors in the mammæ, parotid, thyroid, liver, and in the mucous membranes of the bowels and the uterus. They may be single or multiple; in the intestine they are usually multiple. In certain locations (e. g., the mammæ) they attain enormous dimensions, and in the ovary tumors of this character may be met with weighing forty or fifty pounds. The true adenoma shows no tendency to infection of neighboring lymphatics, and gives rise to no secondary deposit, and when it causes death it is usually because of size or pressure upon important organs. It displays a marked tendency to cystic alteration, while the relative proportion of epithelium and connective tissue or stroma varies within wide limits. In some cases, in which the former is small in amount, the preponderance of the latter has caused the use of the term adenosarcoma, which is really a misleading name.
The distinction between adenoma and true carcinoma is in some respects but slight, and this fact will account for the conversion which many innocent gland tumors seem to undergo from one into the other. As soon as the epithelial cells lose their regularity of disposition and collect in groups, or make their way outside of the acini into the tissues, then the change from the benign to the malignant tumor has begun, and the entire clinical aspect of the case has altered. This change may be the result of external irritation, of such tissue changes as pregnancy and lactation, or of the undefined changes which advancing years seem to produce. (See [Plate XXII, Fig. 2].)
Adenoma occurs in the breast as cystic adenoma or fibro-adenoma. The former often attains large size, is encapsulated, the acini are much dilated, while from the walls of the epithelium-lined cavities frequently project papillomatous processes, forming what are called intracystic growths. Cystic adenomas grow slowly, produce atrophy of mammary tissue by pressure, occur after puberty until the menopause, and rarely give rise to pain until they become large. As they grow they distort the breast until it may become pendulous. When the growth of connective tissue, peculiar to the tumor in that it is rich in nuclei, forms well-marked partitions between alveoli, the growth is called pericanalicular adenofibroma, which may assume a tubular or an acinose type. When the alveoli and ducts are themselves invaded by ingrowth of this tissue, then we have the intracanalicular adenofibroma, which constitutes a growth sometimes bordering on the malignant. When the arrangement of epithelial cells in the acini and ducts becomes irregular and atypical, then malignant transformation has begun.