Human oesophagostomiasis: a histomorphometric study of 13 new cases in northern Ghana.

Oesophagostomiasis is an infrequently described and recognised parasitic infection in humans, caused by Oesophagostomum bifurcum. Although the disease is most often found in the northern part of Togo and the neighbouring part of Ghana, sporadic cases have been described in other parts of Africa and in Asia and South America: Uganda, Ivory Coast, Sudan, Kenya, Ethiopia, Indonesia, Malaysia and Brazil. Infection probably occurs by way of the ingestion of L3 larvae. These larvae penetrate the intestinal wall, especially that of the colon. Some of these larvae develop into young adult worms and return to the bowel lumen. Other larvae, however, develop into immature worms, which fail to settle in the lumen, forming abscesses in the bowel wall and causing pathology. In the literature 105 human cases have been described, many originating in the northern regions of Ghana and Togo. The present study was performed to evaluate 13 new cases originating in the northern part of Ghana (7 female and 6 male patients, aged between 2 and 60 years). Histopathologically, the patients could be divided into two groups: the first group showed multinodular disease, while patients in the second group presented with a single, nodular mass. In the first group, abscesses were seen throughout the colonic wall. The mean size of the cavities was 4.3+/-0.7 mm. There was no relation between the size and the localisation in the colonic wall. Abscesses were significantly larger in male patients than in female patients. There was no correlation with age. In the second group, histopathological examination showed a cyst of variable wall thickness with very limited inflammation. These cysts represented older lesions, often encapsulated in the mesentery. In conclusion, in this study we present 13 new cases of human oesophagostomiasis. The abscess formation was found to be organ specific, independent of age, and gender-related, producing a more intense tissue reaction in male patients.

Clinical epidemiology and classification of human oesophagostomiasis.

The intestinal helminth Oesophagostomum bifurcum is highly and focally endemic in northern Ghana and Togo, and its juveniles produce a nodular inflammatory response as they develop in the intestinal wall. This pathology can produce clinical symptoms. We report on 156 cases of oesophagostomiasis presenting in 1996-98 to Nalerigu hospital in northern Ghana. The disease accounted for 0.2% of the out-patient department new presentations (about 1 patient per week), and 1% (16) of the major acute surgical cases. Children aged 5-9 years were most commonly affected. Multinodular disease (13% of the cases) results from hundreds of pea-sized nodules within the colon wall and other intra-abdominal structures, and presents with general abdominal pain, persistent diarrhoea and weight loss. Dapaong tumour (87%) presents as an abdominal inflammatory mass often associated with fever. The 3-6-cm tumour is painful, well-delineated, smooth, spherical, 'wooden', periumbilical, and adhered to the abdominal wall. Cases most commonly presented during the late rains and early dry season. Diagnosis by ultrasound has reduced the need for exploratory surgery, and the ability to sonographically evaluate conservative treatment with albendazole has curtailed management by colectomy or incision and drainage.

Ultrasound diagnosis of oesophagostomiasis.

Human infection with Oesophagostomum bifurcum, a parasitic intestinal helminth, is endemic in parts of West Africa. Oesophagostomum bifurcum juveniles develop in the colonic wall, causing pus-filled granulomas. The pathology has two distinct forms. Multinodular oesophagostomiasis comprises hundreds of small nodules within a thickened, oedematous wall of the large intestine. Uninodular oesophagostomiasis, called the Dapaong tumour, presents as a painful 30-60 mm granulomatous mass in the abdominal wall or within the abdominal cavity. Diagnosis of oesophagostomiasis on clinical grounds alone is difficult. We describe cases illustrating the ultrasound appearance of these two presentations. Multinodular disease shows nodular "target" and "pseudokidney" colonic lesions. The Dapaong tumour is an echo-free ovoid lumen enveloped within a well defined poorly reflective wall.

Rectal bleeding due to Oesophagostomum brumpti: report of a case.

A case of oesophagostomiasis of the large intestine in a black Ethiopian sailor is described. Diagnosis was made histologically by finding the parasite in nodules of the intestinal wall. A review of the literature is included.

Helminthic pseudotumours of the bowel: thirty-four cases of helminthoma.

Human infestation with nematode worms of the superfamily Strongyloidea has been recorded from time to time to give rise to serious surgical complications. Worms of the genus Oesophagostomum are most frequently responsible. These are common parasites of ruminants, monkeys, and apes in which their histotropic phase is confined to the bowel wall and sometimes results in multiple inflammatory nodules. Man is an accidental host and it seems an abnormal one. The worm fails to return to the bowel lumen, migrates further and persists in the tissues. The commonest manifestation is a solitary tumour-like inflammatory mass or abscess (;helminthoma') in the ileocaecal region. The ileum, transverse and sigmoid colons are affected less commonly and the lesions are occasionally multiple. Patients may also present with abscesses of the abdominal wall. The clinical diagnosis is difficult, even at laparotomy. Carcinoma, appendicitis, ileocaecal tuberculosis are frequently simulated and unnecessary radical surgery is often the result, particularly in expatriate Europeans. In this communication 34 cases from Uganda are reviewed with emphasis on histopathology as responsibility for the correct diagnosis is likely to fall on pathologists. Three characteristic appearances are described and related to phases in the natural history of the disease. Current knowledge on parasitology is reviewed. The disease affects Africans as well as Europeans and it is anticipated that cases will be seen in those returning from the tropics.