Heidrun Rotterdam

AIDS: an overview of the pathology.

This article reviews the findings at postmortem examination on AIDS and separately details the surgical pathology of the gastrointestinal tract, liver, lymph nodes, and skin in these patients. Emphasis is placed upon the light microscopic features of the specimens commonly received in surgical pathology so as the promote the ready diagnosis of this important and grave disorder.

Carcinoma of the Stomach

Carcinoma of the stomach was the leading cause of cancer death at the beginning of the century, but presently in the United States, ranks sixth among cancer deaths and third among malignant tumors of the gastrointestinal tract. The yearly death toll is approximately 14,000 (i. e., half the mortality of 1948).1 The incidence of the disease has declined steadily over the last decades as reflected by the change in the age-adjusted death rates. The death rate in the United States was 10 men and 5 women per 100,000 population in 1965 as opposed to 6.8 and 3.2 in 1976.2 For 1984, however, the comparable figures are higher as 8 per 100,000 men and 4 per 100,000 women died of gastric cancer.3 The estimated number of new cases has also increased slightly, and was reported as 23,000 in 1979, 23,900 in 1981, 24,000 in 1982, and 24,600 in 1987.3

Hyperplasias and Benign Epithelial Tumors

This term includes a group of uncommon to very rare disorders having in common the accentuation of the rugal folds, in part by an increased thickness of the gastric mucosa and in part, as Appelman1 points out, by exaggeration of the submucosal folds. It includes at least four clinical and histologic entities to which a bewildering prolixity of terms have been applied. The best defined of these is the Zollinger-Ellison syndrome, which is discussed in Chapter 5 on peptic ulceration. Appelman has critically reviewed many of the problems of nomenclature and lack of clear criteria which seem to serve chiefly to illustrate, and perhaps even contribute to, the lack of understanding of the disorders discussed.

Gastric Smooth Muscle, Nerve Sheath, and Related Tumors

Small gastric smooth muscle tumors are common in adults at autopsy. Meissner in 19441 observed them in almost 50% of such cases by careful manual examination of the stomach wall. More recently, microleiomyomas of 5 mm or less diameter were detected in 16.4% of resected stomachs, mostly in the upper half.2 Thus, the larger leiomyomatous tumors of the stomach must, in current parlance, be suspected of possessing increased receptor activity for certain undefined growth factors. Platelet- xderived growth factor (PDGF), a smooth muscle growth stimulant, might be involved.3 Estrogens, of course, stimulate uterine leiomyoma growth, which ceases in their absence, but estrogens do not appear to affect similar gastric tumors that are equally common in men and women. Clinically, gastric smooth muscle tumors, benign or malignant, are asymptomatic when small unless they ulcerate and bleed. Larger solid intramural stomach tumors are spheroidal and may bulge into the lumen, stretch the serosa, or both. The classic radiologic and endoscopic appearance of gastric leiomyoma or leiomyosarcoma is a protrusive hemispherical mass in the fundus or body of the stomach, which stretches the mucosa and has an apical central volcano-like cratered ulcer that bleeds.

Carcinoma of the Duodenum

Primary duodenal carcinoma is rare, and only approximately 700 cases had been reported in the literature by 1974 (i.e., within the two centuries following the first description in 1746).1 The files of the Mayo Clinic contained 104 cases for the 40-year period from 1937 to 1977,2 yielding an incidence of 2 to 3 cases per year. In the New York Hospital—Cornell Medical Center, only 32 cases were found in 38 years.3 The incidence at autopsy is between 0.019 and 0.5%.3 The proportion of duodenal carcinomas among gastrointestinal carcinomas is 0.35%.4 Interestingly, however, the duodenum is the preferential site of origin of small intestinal carcinomas, 33 to 45% of which arise there, according to data collected between 1937 and 1963.5 More recent reviews of small intestinal carcinomas yield still higher incidences of 48 and 54%.6,7 As Jefferson8 said in 1916, “Inch for inch the duodenum is more liable to cancer than the rest of the small intestine.” Carcinoma accounts for 70 to 80% of all duodenal malignant tumors; the remainder includes lymphoma, leiomyosarcoma, and carcinoid tumor.1

Carcinoid (Neuroendocrine) Tumors

The nomenclature of carcinoid tumors in general and of gastrointestinal carcinoid tumors in particular has undergone periodic changes reflecting changing concepts of their origin, histologic spectrum, natural history, and embryologic derivation.1 It is certain that at the time of this writing not all that there is to know about these tumors is known, and therefore, the nomenclature is bound to undergo additional changes in the future.

The Normal Stomach and Duodenum

The gastrointestinal tract is derived from the entodermal germ layer, which can be distinguished as a sheet of flat epithelial cells between the ectodermal disc and the blastocyst cavity when the embryo is 8 days old.1 During the subsequent week, the entodermal cells extend along the wall of the blastocyst cavity until, by the 15th day, they form its entire lining.2 The formation of head and tail folds results in a division of the entodermlined cavity into an intraembryonic portion, the primitive gut, and two extraembryonic portions, the yolk sac and the allantois.

Reactive and Neoplastic Lymphoid Lesions

Involvement of the gastrointestinal tract by malignant lymphoma is a common phenomenon judging from autopsy series. Two large autopsy series, which used the older classification, reported 40 to 82% of reticulum cell sarcomas, 42 to 52% of lymphosarcomas, and 13 to 20% of cases of Hodgkin’s disease to have at least microscopic evidence of gastrointestinal involvement at the time of death.1,2 The lower figures are from a series in which only stomach involvement was considered.1 Most such involvement was late in the disease and often incidental.

Miscellaneous Gastroduodenal Pathology

Foreign bodies in the stomach and duodenum can be categorized into three types: true foreign bodies (i.e., environmental objects that should normally never be in stomach or duodenum); bezoars, or foreign bodies composed of substances that normally pass through the gastrointestinal tract in small quantities; and bodies that are foreign to the stomach or duodenum, but not to the human body as such.