Tubercle

A tubercle is a solid elevation of the skin, larger than a papule, but agreeing with it in other respects and capable of undergoing the same changes - namely, absorption, pul­sation, ulceration, or indefinite prolongations.

The principal diseases in which tubercles are found, and their chief features are:

1. Acne;  Tubercles on face,  back,  etc., with inflamed bases, and usually terminating with suppuration.
2. Fibroma;  Single or multiple,  and scattered over  all parts of the body.
3. Framboesia;  Fungous  tubercles,  frequently of large size - very rare.
4. Keloid; Flat tubercles, or flattened elevations of the skin, with projecting finger-like processes.
5. Lentigo maligna; Commencing as macules, becoming papules, and afterward tubercles, frequently with ulceration.
6. Leprosy;  Reddish-brown tubercles  on the forehead, ears, and other parts of face and body.
7. Lupus; Solitary or but few reddish-violet tubercles, of very slow increase, and terminating with ulceration.
8. Morphoea; Flat, light-colored tubercles, followed by atrophy, from one to a dozen - rarely more.
9. Rosacea hypertrophica; Confined to the nose.
10. Syphilis;  Copper-colored, terminating with suppurration or ulceration. In early syphilis, numerous; in late syphilis,   number   of   lesions   limited,   and   occurring   in groups.