Fungous tumors are either large or small. Occasionally a basal-celled neoplasm may be fungating from the beginning, but this is rare, and this characteristic is usually of late development. Fungation is caused by the cancer cells proliferating more rapidly than they can invade, so that the growth must necessarily be outward. The fungating surface may be covered with a slight scab, but frequently this is almost entirely lacking. The surface of the cancerous tissue is comparatively smooth, having but little of the rough, scraggly surface so characteristic of the prickle-celled tumors; in fact, it is even smoother than in cases of blastomycosis or papillary eczema. Again, the tissue resembles anemic granulation tissue, although slight trauma will cause free bleeding. In the smaller tumors the growth is very slow, and there is comparatively little induration beneath the surrounding skin. Sometimes a preexisting ulcer, either cancerous or otherwise, will suddenly begin to fungate, a sure sign of renewed activity and rapid growth. And yet even in these cases metastatic growths do not occur. It is not unusual for the x-ray, radium, the ineffective use of caustics, or even of the curette combined with caustics to set up such a condition.
*Hartzell: Jour. Amer. Med. Assn., 1909, Mi, 262. •Fordyce: Jour. Amer. Med. Assn., 1908, li, 398. "Pernet: Ikonographia Dermat., 1912, vi, 243.
Histologically, these fungating tumors show either an acinous or a stellate arrangement of the cancer cells.
This class of neoplasms must be told from the rapidly growing fungating type of squamous-celled cancer, as well as from certain of the infections, as granulomata (granuloma pyogeni-cum, botryomycosis), recently so ably described by both Sutton* and Wile,* dermatitis vegetans, papillary eczema, blastomycosis, and simple exuberant granulation tissue.