There are rarer pathological changes. In catarrh of long duration cysts are found, especially in the large intestine. They are about the size of a small pea, projecting above the mucous surface. They have a yellow or amber color, and contain a jelly-like yellow fluid which can be pressed out. They originate in the distension of the dilating glands of Lieberkühn; according to Woodward, they find a favorable nidus for their growth in the softening tissue of the solitary glands; hence the cystic forms are seen occupying the interior of follicles undergoing disintegration.21 The presence of the glands of Lieberkühn in the interior of the closed follicles has been observed by other pathologists, some of whom are unable to explain so remarkable a lesion.22 Around the edges or in the midst of healing ulcers in the intestine granulation-like excrescences or polypoid growths are observed as a rare lesion. These seem to be projections from undestroyed islands of mucous membrane, being surrounded by the ulcerated surface. The minute polypi originate in a process of growth of the undestroyed mucous tissue. Cicatricial contractions around their bases give them peculiar forms; they are club-shaped, simple, or branched. This lesion has been described by Johann Wagner,23 Carl Rokitansky,24 and J. J. Woodward25 from original specimens. According to Woodward, the growths (pseudo-polypi he calls them) are composed of a central portion of connective tissue continuous with the submucous connective tissue of the intestine and a peripheral portion of diseased mucous membrane. The central connective tissue was filled with large and numerous cells, and the glands of Lieberkühn in the mucous covering were elongated and branched and showed evidences of an active hyperplasia.
21 J. J. Woodward, op. cit., pp. 570, 571.
22 A. Laboulbène, Anat. path., Paris, 1879, p. 186.
23 "Einige Formen von Darmgeschwüren; iii., die Dysenterische Darmverschwärung," Med. Jahrb. des k. k. öst. Staates, Bd. xi., 1832, S. 274.
24 "Der dysenterische Prozess auf dem Dickdarme und der ihm gleiche am Uterus, vom anatomischen Gesichtspuncte, beleuchtet," ibid., Bd. xxix., 1839, S. 88.
25 "Pseudo-polypi of the Colon," Am. Journ. Med. Sci., Jan., 1881, p. 142.
Polypi of the colon have been seen and figured by other pathologists, but they were not connected with ulceration and cicatrization of ulcers. Luschka26 saw the mucous membrane from the ileo-cæcal valve to the end of the rectum covered with polypi, club-shaped, the size of a hempseed or bean, and made up of glandular tubes simple or branched. Other cases have been described by Lebert, Heuriet, and others,27 in which polypi were distributed in the rectum, colon, cæcum, or about the ileo-cæcal valve. This is the condition described by Virchow as colitis polyposa.
26 Virchow's Archiv, vol. xx. p. 133.
27 Heuriet, Bull. de la Soc. Anat. Paris, t. xlviii., 1873, p. 250; Tr. N.Y. Path. Soc., vol. ii., 1877, p. 172. For illustration of multiple polypi of colon and rectum, Lebert, Path. Anat., tome ii., Pl. cxxii. figs. 1 and 2; granular elevations in ileum, idem, Pl. cxxi. fig. 1. Also, mucous polypi of rectum, Thierfelder, Tab. xiii. figs. 3, 3a, 3c; also, intestinal polypi of rectum, Lancereaux, Atlas Path. anat., 1871, Paris, Pl. iv. fig. 4. Polypi are rarely seen in the small intestine; see Böttcher, "Polypöses Myom des Ileums," Archiv der Heilkunde, xi. Jahrgang, 1870, p. 125.
Atrophy of the wall of the intestine, chiefly of the mucous layer, supervenes upon catarrh. It is confined to certain areas, the rest being normal or in a state of chronic catarrh. It is found in 80 per cent. of the cases examined either in the large or small intestine. The cæcum is the most frequent seat; next in the order of frequency it is seen in the ascending colon, the lower part of the ileum, the other parts of the colon, and is least common in the upper part of the ileum. In children the lesion is more common in the small intestine than in adults. The changes in the mucous membrane of the colon are a diminution in its thickness and disappearance of the glands of Lieberkühn. The mucous layer is reduced to one-fifth of its normal size, and no trace of the glands may be left; a layer of connective tissue with imbedded round cells is all that remains. The surface of the membrane is irregular and colored with yellowish pigment. In the ileum the villi are shrunken, with few cells; in some cases they disappear altogether. The muscular tunic may share in the atrophy.28