Gut: first published as 10.1136/gut.24.6.575 on 1 June 1983. Downloaded from Gut, 1983, 24, 575-578 Case report Enterochromaffin cell hyperplasia and megacolon: report of a case G B M LINDOP From the Department of Pathology, University of Glasgow, Western Infirmary, Glasgow SUMMARY A case of megacolon is described in which there was an unusual and focal hyperplasia of enterochromaffin cells in the mucosa. These formed discrete spherical acini in the lamina propria. These acini were not neoplastic and their significance is discussed. Enterochromaffin cells are found in the gut This time he was taken to theatre where a large epithelium from the gastro-oesophageal junction to redundant loop of sigmoid colon was resected and the anus.' 2 As their secretion of 5-hydroxy- an end-to-end anastomosis carried out. tryptamine and polypeptide hormones are thought to be important in the regulation of gut motility2-5 PATHOLOGY they have been studied in a variety of disorders. This The specimen was a 50 cm long piece of colon. It paper reports the study of a case of megacolon in was markedly dilated and hypertrophied, its which enterochromaffin cells were not only maximum width when opened being 21 cm and the http://gut.bmj.com/ markedly increased in number, but were disposed in muscle coat attaining a thickness of 6 mm. discrete acini in the lamina propria separate from Histological sections taken from the full length the overlying epithelium. and breadth of the specimen were examined. Examination of these confirmed the muscular Case report hypertrophy and showed several abnormalities in The patient, a 28 year old man, first came to medical the mucosa. Most strikingly, there was marked attention six years ago complaining of intermittent hyperplasia of the enterochromaffin cells which are on September 30, 2021 by guest. Protected copyright. abdominal distension and discomfort over the normally fairly scanty in large bowel epithelium.2 previous three to four years. On examination, his Instead of being situated singly, mainly at the base rectum was anaesthetic and full of faeces and he was of the glands, they were present in groups and in the thought to have faecal retention owing to faulty surface epithelium. In addition, some sections bowel habit. In the following few years, while showed the presence of definite acini composed only attempts were being made to correct his bowel of enterochromaffin cells and scattered sparsely in habit, he had several episodes of large bowel the mucosa (Fig. 1). They were present at all levels obstruction which were relieved by enemas given by in the lamina propria but were confined to the his general practitioner. During this time, a barium mucosa. They were mainly disposed singly, but enema showed faecal retention and suggested the occasionally in groups of two or three. Serial diagnosis of idiopathic megacolon. sections showed that they were roughly spherical He was eventually admitted to hospital six years acini with a small central lumen which sometimes later with large bowel obstruction which was contained a small amount of eosinophilic material thought clinically and radiologically to be because of (Fig. 2). The acini did not communicate with one a volvulus of his sigmoid colon. His condition another nor with rectal glands. Histochemical improved markedly with conservative treatment, studies showed these acini to be strongly stained by but one week later he again developed obstruction. both the diazo and Masson-Fontana techniques (Fig. 2 and 3) as were the enterochromaffin cells in the surface epithelium and glands. Their fine Received for publication 13 September 1982 structure, within the limits imposed by formalin 575 Gut: first published as 10.1136/gut.24.6.575 on 1 June 1983. Downloaded from 576 Lindop , dS0XEf<00000f:00:j http://gut.bmj.com/ .i!s,X,9tSi!1!goo^,00W0;08,t,^+i .o;;. Fig. 2 Enterochromaffin cell acinus near surface ofthe Fig. 1 Colonic mucosa showing irregularity ofglands and mucosa with normal enterochromaffin cells in adjacent two acini composed entirely ofenterochromaffin cells epithelium for comparison. Note lumen which contains (arrowed) Haematoxylin and eosin xlO0 (original small amount ofamorphous material. Masson Fontana magnification). x250 (original magnification). on September 30, 2021 by guest. Protected copyright. fixation, was that of normal enterochromaffin cells Cryostat sections of 100-300 g in thickness were except that they were slightly larger and contained cut parallel to the lumen at various areas of the more secretory granules than the normal entero- colon. These were stained by a silver impregnation chromaffin cells in the surface epithelium (Fig. 4 technique,6 and examined by the method of Smith7 and 5). to show the nerve plexuses. These showed no The distribution of these enterochromaffin acini definite abnormality when compared with similar within the specimen was limited to a transverse band sections from normal parts of colons excised for about 10 cm wide ending approximately 8 cm from carcinoma. the distal end of the specimen. Within this band the acini were sparsely distributed and were not present Discussion elsewhere in the specimen. There was no evidence that these were neoplastic in nature. Study of many Enterochromaffin cells in the colon are normally tissue sections revealed occasional areas which found singly in the epithelium, predominantly of the suggested that these acini were formed from groups lower parts of the glands.3 They are thought to be of enterochromaffin cells in the gland or surface important in regulating the motility of the gut.3-5 In epithelium (Fig. 3). the present case, the enterochromaffin cell acini are Other mucosal abnormalities were branching and clearly not part of a carcinoid tumour. There are loss of parallelism of the glands and the presence of three main possibilities: they may be a macrophages filled with mucin in the lamina propria hamartomatous malformation, perhaps analgous to (Fig. 3). cutaneous naevi; they may be an unusual response Gut: first published as 10.1136/gut.24.6.575 on 1 June 1983. Downloaded from Enterochromaffin cell hyperplasia and megacolon: report of a case 577 Fig. 3 Enterochromaffin cell acinus which appears to be formedfrom group ofenterochromaffin cells in surface epithelium. Note numerous enterochromaffin cells in e~ http://gut.bmj.com/ adjacent epithelium and mucin-containing macrophages in ~ar lamina propria (arrowed). Diazo x250 (original magnification). Fig. 5 Fine structure ofthe enterochromaffin cells ofacini showing abundant secretory granules. Electron micrograph (formalinfixation) x22000 (original magnification). on September 30, 2021 by guest. Protected copyright. to functional hyperplasia; or they may be a preneoplastic lesion. The presence of hyperplasia of the enterochromaffin cell population in the overlying epithelium and the histological appearances illustrated in Fig. 3 may be evidence that the formation of acini is a response to proliferation of enterochromaffin cells in the surface epithelium. Argyrophilic 'endocrine-like' cells were described as forming groups of two to five cells in the lamina propria in cases of chronic gastritis8 9 but these authors did not comment on the total number present in the mucosa. In a study of 1200 appendices Massonlo described enterochromaffin cells migrating from the gland epithelium into the lamina propria; Rarely a process of 'bourgeonnement' or budding was observed where the enterochromaffin cells formed acinar structures within the lamina Fig. 4 Enterochromaffin cell acinus between two mucosal propria. These resembled the appearances described glands. Electron micrograph (formalinfixation) x 1700 here. A similar budding process was called (original magnification). 'endophytie' by Feyrterll who postulated that the Gut: first published as 10.1136/gut.24.6.575 on 1 June 1983. Downloaded from 578 Lindop pancreatic endocrine cells originated from such a References process of budding from foregut endoderm. The relationship of the argentaffin cell hyper- 1 Haverback BJ, Davidson JD. Serotonin and the plasia to the megacolon seems obscure. On the one gastrointestinal tract. Gastroenterology 1958; 35: 570- hand, it seems unlikely that hyperplasia of the 8. enterochromaffin cells caused the megacolon as the 2 Tobe T, Fujiwara M, Tanaka C. The distribution of hyperplasia is focal and the maximum hyperplasia is serotonin (5-hydroxytryptamine) in the human gastro- not present at the most distal aspect of the intestinal tract. Am J Gastroenterol 1966; 46: 34-7. megacolon. On the other hand, it seems unlikely 3 Solcia EL, Polak JM, Pearse AGE et al. Classification of gastro entero pancreatic endocrine cells. In: Bloom that megacolon would produce a focal hyperplasia, SR, ed. Gut hormones. Edinburgh: Churchill and hyperplasia of enterochromaffin cells is not Livingstone, 1978: 40-8. known to be associated with megacolon which is a 4 Bulbring E, Lin RCY. The effect of intraluminal common condition. Thus it seems unlikely that the application of 5-hydroxy-tryptamine and 5- hyperplasia was secondary to the megacolon. It is hydroxytrytophan on peristalsis: the local production of therefore possible that this is a chance association. 5-hydroxytryptamine and its release in relation to Enterochromaffin cell hyperplasia has been intraluminal pressure and propulsive activity. J Physiol described in some other gut disorders - untreated 1958; 192: 823-46. and the chronic gastritis of 5 Pentilla A, Lempinen M. Enterochromaffin cells and coeliac disease12 5-hydroxytryptamine in the human intestinal tract. pernicious anaemia. 13 Similarly, in Masson'slO Gastroenterology 1968; 54: 375-81. massive study of the appendix already mentioned 6 Schofield GC. Experimental studies on the innervation the hyperplastic enterochromaffin cells occurred in of the mucous membrane of the gut. Brain 1960; 83: cases of chronic obliterative appendicitis with neural 490-512. hyperplasia. In all of these diseases the role of the 7 Smith B. The myenteric plexus in Hirschsprung's enterochromaffin cell hyperplasia is unclear. disease. Gut 1967; 8: 308-12. Chronic inflammation, however, may be the linking 8 Stachura J, Urban A, Bigaj M et al.