DIAGNOSIS.—Generally very difficult. The progress of the disease is ordinarily slow, and follows its development in other portions of the body. Cancerous cachexia, degeneration of the glands above the clavicle, hæmothorax, and hemorrhagic pleurisy, together with dry cough and persistent intercostal neuralgia, are, when present, valuable aids to diagnosis. Extensive caseous pneumonia and pleuritic effusions may be confounded with cancer of the pleura. These tumors may not be at the base, but in the middle of the thorax; dulness may not exist at the base as is invariably the case in pleurisy. The position of the body does not affect the limit of dulness in cancer.
The PROGNOSIS is always very serious, the disease being invariably fatal. In Walshe's cases the duration of the disease was from three and one-half months to twenty-seven months; average duration, thirteen and one-fifth months. One-fourth of his cases occurred between the ages of fifty and sixty years.
The TREATMENT is palliative—opium and other narcotics, and locally chloroform and aconite for the intercostal pains. When effusion results from cancerous inflammation the aspirator may be used to relieve the great oppression caused by the quantity of fluid.
Hydatids of the Pleura.
Trousseau258 considered hydatids of the pleura a comparatively rare disease. He believed that when found in the cavity it was frequently caused by cysts of the lung which had fallen into the pleural cavity. Vigla259 mentions 3 cases. Davaine260 met with 25 cases of hydatids, only 1 of which he believed originated in the pleural cavity. The acknowledged greater frequency of these hydatids in the right inferior lobe of the lung, gives probability to Dolbeau's261 view that "they frequently proceed from cysts on the convex surface of the liver." Hearn262 reports 75 cases collected from various observers as intra-thoracic, 15 of which were in the pleura, in the subserous tissue, between the parietal pleura and thoracic wall.
258 Clin. Med., vol. i., Philada. ed.
259 "Des Hydàtides intrathor.," Arch. gén., 1855.
260 Traité des Entozoaires, etc., Paris, 1860.
261 Thèse de Paris, 1856.