Sarcoma of various types is met with in the skin. The fibroma, after excision, may recur as a fibro-sarcoma. The alveolar sarcoma commences as a hard lump and increases in size until the epidermis gives way and an ulcer is formed.
Fig. 105.—Melanotic Cancer of Forehead with Metastases in Lymph Vessels and Glands.
(Mr. D. P. D. Wilkie's case.)
A number of fresh tumours may spring up around the original growth. Sometimes the primary growth appears in the form of multiple nodules which tend to become confluent. Excision, unless performed early, is of little avail, and in any case should be followed up by exposure to radium.
Affections of Cicatrices
A cicatrix or scar consists of closely packed bundles of white fibres covered by epidermis; the skin glands and hair follicles are usually absent. The size, shape, and level of the cicatrix depend upon the conditions which preceded healing.
A healthy scar, when recently formed, has a smooth, glossy surface of a pinkish colour, which tends to become whiter as a result of obliteration of the blood vessels concerned in its formation.
Weak Scars.—A scar is said to be weak when it readily breaks down as a result of irritation or pressure. The scars resulting from severe burns and those over amputation stumps are especially liable to break down from trivial causes. The treatment is to excise the weak portion of the scar and bring the edges of the gap together.