Amyloid processes within the intestine were first described by Virchow 1 in 1855. The amyloid changes start in the walls of the small blood-vessels (capillaries and the finest arteries, occasionally also the veins).

At first the vessels of the mucosa alone are affected, but afterward the process may extend through the submucosa and even through the entire intestinal wall down to the serous layer. The amyloid degeneration may also involve the muscularis mucosae, or even the entire muscular layer of the intestinal walls. The amyloid degeneration of the blood-vessels makes them friable, thereby often leading to necrotic processes with the formation of small ulcers.

1 R. Virchow: "Ueber den Gang der amyloiden Degeneration." Virchow's Arch., Bd. 8.

Amyloid changes are found more often in the small intestine than in the large bowel. The mucous membrane of the affected part has a waxy and pale appearance. The villi are missing here and there.

The diagnosis can be positively made by means of the characteristic color tests. A solution of iodine poured over the suspected area gives a brownish-red color which becomes violet or blue after the addition of sulphuric acid; a solution of methyl violet produces a bright pink color.

We have reason to suspect amyloid processes within the intestine in conditions which are known to be often associated with this process, as tuberculosis, syphilis, leukaemia. Especially is this true if amyloid degeneration is detected in other organs (spleen and liver) as shown by their enlargement, and besides there are signs of chronic diarrhoea and insufficient intestinal absorption. There are, however, no positive means of establishing the diagnosis of amyloid degeneration of the intestine during life.