—These include many of those which grow in the nose. The pure form of nasal myoma proceeds from the mucous membrane of the nasal passages or sometimes from the accessory sinuses. But most of the so-called nasal polypi are due to edematous hypertrophies of the submucosa. The polypi usually hang as gelatinous tumors of grayish-yellow tint, being present sometimes singly, sometimes in clusters or in large numbers. Their principal effect is to produce nasal obstruction, with, perhaps, subsequent serious disorder, due to decomposition or to extension into the pharynx or other cavities. Similar growths also occur from the mucous membrane of the tympanum, and constitute the common variety of aural polypi.
2. Cutaneous Myxoma.
—Cutaneous myoma is not common. It presents usually as a sessile tumor, although about the perineum and labia the tumors may become pedunculated. It is often difficult to distinguish between a myoma of the skin and a sarcoma of the same which has undergone myxomatous degeneration, and which then should be called sarcoma myxomatodes. The latter tend to recur after removal; hence the importance of exact diagnosis.
3. Neuromyxoma.
Neuromyxoma is a similar condition involving the nerve trunks, and is dealt with under Neuroma.
Myxomas require complete removal, and, in the nose especially, cauterization or destruction of the surface from which they spring. When this is thoroughly done they do not recur; otherwise, they are likely to require subsequent operation.
Myoma.
—The true myoma is a tumor composed of unstriped or involuntary muscle fiber. Until recently it has been customary to divide the myomas into the leiomyomas in contradistinction to the rhabdomyomas, the latter being supposed to be tumors of voluntary muscle fiber. Myomas are met with only where involuntary muscle fiber is found—namely, in the uterus and adnexa, the vagina, the esophagus, alimentary canal, the prostate, the bladder, and the skin. They form encapsulated tumors composed of fusiform muscle cells with a rod-like nucleus, the size of the cells varying greatly in different specimens. The bundles of muscle fibers are much contorted, and it is often difficult in a single section to decide to just what class of cells they belong.
These tumors are most common in and about the uterus, and are referred to as intramural when developing in the true uterine tissue, and submucous and subserous when situated just beneath one or the other of the adjoining membranes. They differ in their rate of growth, are firm in composition, and are moderately vascular, sometimes containing areas of softening and becoming even cystic. In rare instances they become enormously vascular, and are then known as cavernous myomas. Aside from mucoid or colloid changes they occasionally undergo fatty metamorphosis or calcareous infiltration. The latter is possible to such an extent as to lead to a condition of uterine calculi.
Uterine myoma is liable to septic infection, which frequently follows exploration of the uterus or the changes incident to pregnancy or parturition. It then becomes a case for immediate operation. Uterine myomas do not occur before puberty, rarely before the age of thirty-five, and are most common between the thirty-fifth and forty-fifth years of life. They produce disaster not alone by their size, but by hemorrhage, by pressure on adjoining viscera (rectum, kidneys, etc.), and occasionally by torsion of a long pedicle.