Histopathological spectrum of nonneoplastic lesions of large intestine- A three year study

Large intestine is a site for an array of different nonneoplastic and neoplastic lesions. Clinical manifestations may overlap, thus making the diagnosis difficult and creating the need for tissue diagnosis. Our study aims at detail histopathological examination of the different non neoplastic lesions of large intestine. A total of 30 nonneoplastic lesions of large intestine were studied over a period of 3 years. Both resected specimens and endoscopic biopsy specimens were included. Histopathological findings were studied along with analysis of the distribution of lesions and correlation of the histopathological findings with clinical parameters. The lesions were distributed in all age groups, with maximum frequency in 5 to 8 decades. The frequency was significantly higher in males (23 cases- 76.7%) as compared to females (7 cases- 23.3%). The most common lesion was perforation (10 cases), followed by gangrene (4 cases). Two cases had gangrene with perforation. Other lesions included Hirschprung’s disease (5 cases), Crohn’s disease (two cases) and one case each of Enteric duplication cyst, tuberculosis, amoebic colitis with perforation and Peutz-Jeghers polyp. Three cases had nonspecific inflammation. Our study emphasizes the importance of histopathological examination in the management of colonic lesions

Characteristics of endoscopic and pathological findings of amebic colitis

Background The clinical features of amoebic colitis resemble those of inflammatory bowel disease (IBD), and therefore the risk of misdiagnosis is very high. The aim of this study was to analyse the characteristics of the endoscopic and pathological findings of amebic colitis and the lessons from our patients, which were useful for diagnosing the amebic colitis timely and avoiding the serious complication. Methods We retrospectively reviewed data of all amebic colitis admitted to Beijing Friendship Hospital from January 2015 to January 2020. Cases were diagnosed by clinical presentation, laboratory examinations, and colonoscopy with biopsy and histological examination, no ELISA stool antigen or PCR tests were used. Results 16 patients were diagnosed with amebic colitis by the colonoscopy accompanied by biopsy and microscopic examination. At first time, 12 (75%) patients were misdiagnosed as IBD. Cecum was the most common site of amebic colitis (100%), and the caecum and rectum were also involved in many lesions (68.75%). Multiple lesions of erosion and/or ulcer were recognized in all patients (100%).The endoscopic findings included multiple irregular shaped ulcers and erosions with surrounding erythema, and the ulcers and erosions were covered by the white or yellow exudates. The intervening mucosae between the ulcers or erosions were normal. The features of rectums can be divided to 2 types: in 6 patients (54.5%), the irregular ulcer or erosions covered with white or yellow exudates were observed in rectum and cecum, and the bloody exudates in rectum were more severe than those in cecum; in other 5 patients (45.5%), rectal lesions were much less severe than those in cecum, the small superficial erosion or reddened mucosa were observed in the rectal ampulla. All patients were diagnosed as detection of amebic trophozoites from HE-stained biopsy specimens. The number of trophozoites ranged from 1/HPF to > 50/HPF. Among 16 cases, mild architectural alteration of colon crypt were observed in 10 cases (62.5%), and serious architectural alteration of colon crypt was found which had crypt branch in 1 case (16.7%). Cryptitis was observed in 12 cases (75%) and its severity was mild or moderate. No crypts abscess was observed in all cases. Conclusions The colonoscopy with histological examination are very important to diagnose the amebic colitis. Detect the amoebic trophozoites in the exudates by histological examination is the vital. Sometimes a negative biopsy does not rule out amebiasis, repeated biopsies may be needed to make the diagnosis.

Fulminant necrotising amoebic colitis after corticosteroid therapy for severe COVID-19

Acute fulminant necrotising colitis is an uncommon presentation of amoebiasis, which can be precipitated after corticosteroid therapy. Clinicians treating patients with COVID-19 with corticosteroid therapy should be familiar with this condition to avoid delay in diagnosis. The disease is associated with high mortality, and prompt diagnosis and management are essential for salvaging patients. We report successful management of a patient who developed this complication following administration of steroids for COVID-19.

1411 Amoebic Colitis: Inaccurate Diagnosis; Inappropriate Surgery

Global prevalence of symptomatic Amoebiasis (pathogen Entamoeba histolytica) is approximately 50 million cases per year, with an annual mortality of up to 100,000. Despite this, a diagnosis of amoebiasis is rarely considered in the UK. Transmission is via the faeco-oral route, person-to-person contact or oral-anal sexual contact. The majority of cases diagnosed in the UK are in international travellers or immigrants. Symptoms of amoebiasis can closely mirror those of Inflammatory Bowel Disease (IBD) resulting in diagnostic uncertainty. A misdiagnosis could result in treatment with corticosteroids, immunosuppressant or biological agents when standard treatment for amoebiasis is actually Metronidazole. In exceptional circumstances, a misdiagnosis of IBD may lead to a patient requiring colectomy and formation of end ileostomy due to an apparent failure of medical management. Emergency colonic surgery is associated with a risk of complications such as wound infections and collections, together with the psychological consequences of major illness and surgery. We report on two patients who have undergone emergency subtotal colectomy and end ileostomy in whom a diagnosis of amoebic colitis was made on histology. Both British Asian patients were under 55 years of age, had a travel history to India and presented with diarrhoea. The diagnosis of amoebiasis must be considered in the differential diagnosis for all returning travellers and immigrants who present with GI symptoms, consistent with IBD. A correct diagnosis allows appropriate, simple, curative treatment and avoids unnecessary surgery with its attendant morbidity. Polymerase chain reaction is the gold standard diagnostic test and is currently significantly under-utilised.

Taxon-Specific Proteins of the Pathogenic Entamoeba Species E. histolytica and E. nuttalli

The human protozoan parasite Entamoeba histolytica can live in the human intestine for months or years without generating any symptoms in the host. For unknown reasons, amoebae can suddenly destroy the intestinal mucosa and become invasive. This can lead to amoebic colitis or extraintestinal amoebiasis whereby the amoebae spread to other organs via the blood vessels, most commonly the liver where abscesses develop. Entamoeba nuttalli is the closest genetic relative of E. histolytica and is found in wild macaques. Another close relative is E. dispar, which asyptomatically infects the human intestine. Although all three species are closely related, only E. histolytica and E. nuttalli are able to penetrate their host’s intestinal epithelium. Lineage-specific genes and gene families may hold the key to understanding differences in virulence among species. Here we discuss those genes found in E. histolytica that have relatives in only one or neither of its sister species, with particular focus on the peptidase, AIG, Ariel, and BspA families.

FULMINANT AMOEBIC COLITIS CAUSING CAECAL GANGRENE WITH RUPTURED LIVER ABSCESS

Liver abscess is the most common extra intestinal manifestation in patients with amoebiasis.Amoebic abscess can present in paracaecal region and liver .Synchronous presence of caecal gangrene with ruptured liver abscess into peritoneum is rare.It has a high rate of morbidity and mortality especially in malnourished patients.Here we present a case of 66 years old male who presented to casualty with complaints of abdomen pain with abdomen distension.Radiological investigations showed ruptured liver abscess.Inview of peritonitis,patient was shifted to emergency theatre for laparotomy.Intraoperative findings were ruptured liver abscess with Caecum found to be sloughed out and gangrenous.Removal of Caecum with limited resection of ascending colon and distal ileum done and bowel exteriorised.Post operatively patient started on oral diet on second day and discharged on seventh day .Patient was readmitted for abdomen pain and percutaneous drainage was done for residual liver abscess.Prompt suspicion of caecal pathology should always be made in patients with ruptured liver abscess and early intervention is needed to prevent mortality