#Myoma.#—­A myoma is composed of non-striped muscle fibres.  A pure myoma is very rare, and is met with in organs possessed of non-striped muscle, such as the stomach, intestine, urinary bladder, and prostate.  In the uterus, which is the most common situation, these tumours contain a considerable admixture of fibrous tissue, and are known as fibroids or fibro-myomas.  They present on section a fasciculated appearance, which may resemble that of a section of balls of cotton (Fig. 54).  They are encapsulated and vascular, frequently attain a large size, and may be single or multiple.  While they may occasion neither inconvenience nor suffering, they frequently give rise to profuse haemorrhage from the uterus, and may cause serious symptoms by pressing injuriously on the ureters or the intestine, or by complicating pregnancy and parturition.

The #Rhabdomyoma# is an extremely rare form of tumour, met with in the kidney, uterus, and testicle.  It contains striped muscle fibres, and is supposed to originate from a residue of muscular tissue which has become sequestrated during development.

[Illustration:  FIG. 54.—­Fibro-myoma of Uterus.

(Anatomical Museum, University of Edinburgh.)]

#Glioma.#—­A glioma is a tumour composed of neuroglia.  It is met with exclusively in the central nervous system, retina, and optic nerve.  It is a slowly growing, soft, ill-defined tumour, which displaces the adjacent nerve centres and nerve tracts, and is liable to become the seat of haemorrhage and thus to give rise to pressure symptoms resembling apoplexy.  The glioma of the retina tends to grow into the vitreous humour and to perforate the globe.  It is usually of the nature of a glio-sarcoma and is highly malignant.

#Endotheliomas# take origin from the endothelium of lymph vessels and blood vessels, and serous cavities.  They show great variation in type, partly because of the number of different kinds of endothelium from which they are derived, and partly because the new connective tissue which is formed is liable to undergo transformation into other tissues.  They may be soft or hard, solid or cystic, diffuse or circumscribed; they grow very slowly, and are almost always innocent, although recurrence has been occasionally observed.  Cases of multiple endotheliomata of the skin have recently been described by Wise.

Angioma, lymphangioma, and neuroma are described with the disease of the individual tissues.

MALIGNANT CONNECTIVE-TISSUE TUMOURS—­SARCOMA