Epithelial cancer has also been observed in those who have taken arsenic over long periods for medicinal purposes.
Fig. 102.—Rodent Cancer of Inner Canthus.
Rodent Cancer (Rodent Ulcer).—This is a cancer originating in the sweat glands or sebaceous follicles, or in the fœtal residues of cutaneous glands. The cells are small and closely packed together in alveoli or in reticulated columns; cell nests are rare. It is remarkably constant in its seat of origin, being nearly always located on the lateral aspect of the nose or in the vicinity of the lower eyelid ([Fig. 102]). It is rare on the trunk or limbs. It commences as a small flattened nodule in the skin, the epidermis over it being stretched and shining. The centre becomes depressed, while the margins extend in the form of an elevated ridge. Sooner or later the epidermis gives way in the centre, exposing a smooth raw surface devoid of granulations.
Fig. 103.—Rodent Cancer of fifteen years' duration, which has destroyed the contents of the Orbit.
(Sir Montagu Cotterill's case)
The margin, while in parts irregular, is typically represented by a well-defined “rolled” border which consists of the peripheral portion of the cancer that has not broken down. The central ulcer may temporarily heal. There is itching but little pain, and the condition progresses extremely slowly; rodent cancers which have existed for many years are frequently met with. The disease attacks and destroys every structure with which it comes in contact, such as the eyelids, the walls of the nasal cavities, and the bones of the face; hence it may produce the most hideous deformities ([Fig. 103]). The patient may succumb to hæmorrhage or to infective complications such as erysipelas or meningitis.