Here also there are several possibilities-first, benign tumors of the ducts, and, second, carcinomata arising from the ducts. Also, it must be remembered that the multiple syringocystadenomata spring from congenitally displaced sweat ducts.

Benign Tumors Of The Ducts

The benign tumors, or syringo-adenomata, are usually solitary, or occasionally multiple tumors, and are apt to appear upon the face as semiglobular nodules, which on palpation are easily distinguished as globular, but which are not adherent to surrounding tissue. They vary in diameter from 1 to 8 cm. Histologically, they consist of many lateral branches from the ducts, the lumens of which may or may not be patent, but the basal membrane of which is never broken through. Besides the increase of epithelial tissue, there is an increase of fibrous tissue as well (Figs. 38, 39).

*Wolfheim: Arch. f. Dermat. u. Syphll., 1907, lxxxv. 277.

Klauber: Beltr. z. kiln. Chir., 1904. xll, 311.

Petersen has described a case of clinical "nevus unius lateralis" which consisted chiefly of a true syringoadenoma, and Unna has had a somewhat similar case, and which he described as "asphyxia reticularis multiplex".

Fig. 39.-Adenoma of sweat ducts. High-power photomicrograph. (Author's collection).

Carcinomata Of The Ducts

Carcinomata of the ducts have not been described, but doubtless occur.

Treatment

The treatment of all of these tumors is fairly definite. When a tumor is clinically benign, it may be treated by simple excision, and, when clinically malignant, by broad local removal, usually without disturbing the lymph glands. If, however, microscopical examination shows a malignant type of carcinoma, the glands should be removed at once. If good frozen sections can be obtained at once, this further operation may be done at the same sitting, as otherwise a second operation is necessary. In inoperable cases one might resort to radium, the x-ray, or the curette and cautery. Irritant pastes should never be used, for the growth is usually too deeply situated to allow of curative results.