BASIDIOBOLOMYCOSIS: AN EMERGING FUNGAL INFECTION OF THE GASTROINTESTINAL TRACT IN ADULTS

Basidiobolomycosis is an unusual fungal infection k nown for dermatological manifestations that affect immunocompetent young adult and rarely involves the gastrointestinal tract, during the past decade man y cases have been reported in Saudi Arabia with diagn osis of gastrointestinal basidiobolomycosis, most o f the reported cases were in children and majority came f rom southern region of Saudi Arabia and all were misdiagnosed initially as either IBD or granulomato us diseases or malignancy. GIB poses diagnostic difficulties due to nonspecific presentations and r arity and has been scarcely reported in medical lit eratures. GIB might be a life threatening infection. So, a hi gh index of suspicion is warranted in any child or y ung adult with differential diagnosis of IBD, granuloma tous disease and malignancy affecting GI tract espe cially those patients whom are residents in or came from s outhern region of Saudi Arabia. In this series whic h is the largest reported series in adult patient with G IB in this country, we describe 4 cases of GI basidiobolomycosis from southern Region of Saudi Ar abia.


INTRODUCTION
Basidiobolus species are filamentous fungi that belong to the family basidiobolaceae, of the order entomophthorales, they are occasionally present as a commensal in the gastrointestinal tract of amphibians, reptiles, fish and mammals such as toads, turtles, chameleons, horses, dogs and bats and it is commonly found in soil and decaying vegetable matter (Greer and Friedman, 1966;Zahari et al., 1990;Gugnani, 1983). In the past, clinical isolates of Basidiobolus were classified as B. ranarum, B. merisstosporus and B.haptosporus. However, recent taxonomic studies based on antigenic analysis, isoenzyme banding and restriction enzyme analysis indicate that all human pathogens belong to B. ranarum (Khan et al., 2001;Sujatha et al., 2003). B. ranarum was first described by Eidam in 1886 as an isolate from frogs and it was later cultured from intestinal contents (Sutherland-Campbell, 1929;Thaxter, 1888) and the excreta of frogs. Basidiobolomycosis in general was recognized as the first human case of subcutaneous mycosis in Indonesia (Joe et al., 1956). Thereafter, start to be increasingly identified as one of the chronic subcutaneous fungal infections with most of the cases have been reported from tropical and subtropical regions (Sugar, 2010) and thought to be due to traumatic inoculation (Cameroon, 1990). GI basidiobolomycosis has been scarcely reported in the literatures and the total reported cases since 1964 till end 2012 were 44 cases worldwide. Recently, its etiologic role in gastrointestinal infections has been increasingly recognized in Saudi Arabia (Jarie et al., 2003;El-Shabrawi et al., 2011;Hussein et al., 2007). To our knowledge 11 cases of GI basidiobolomycosis have been reported in Saudi Arabia: 10 cases in children and 1 case in young adult most of them came from southern region.

Case Definition
Each case was diagnosed based on typical histopathology findings (granulomatous inflammation with tissue eosinophilia and presence of broad fungal hyphae on Gomorimethenamine silver stain) and isolation of B. ranarumfrom colonoscopic biopsies or surgical specimens.

Medical Record Review
Health records of four adult patient (≥18 years of age) with GIB were retrospectively reviewed. All of those patient were diagnosed at Aseer Central Hospital (A tertiary health care center in southern region of Saudi Arabia). Data collected included symptoms, signs, laboratory, radiologic studies, endoscopic features, surgical interventions, treatment and outcome. Table 1 provides detailed clinical, laboratory, radiological, endoscopic features, surgical interventions and outcome of all patients included. In this series, all the cases were misdiagnosed initially: two as colon cancer; one as IBD; one as appendicitis. The colon was involved in all of them with initial presenting symptoms of abdominal pain and fever in all patients; abdominal mass in three patients; marked weight loss in three patients and diarrhea in two patients. All patients had high ESR and hypochromic microcytic anemia; three had leukocytosis among them two had eosinophilia. Colonoscopy wise all had severe deep bleeding ulcers and three of them had fungating masses. Radiologically, one patient presented with huge dilatation of large bowel without real obstruction which was not reported before and three patients presented with masses. One patient responded well to treatment; three patients died from advanced disease and hospital acquired infections. One of them complicated by fistulae formation mimicking Crohn's disease which also, up to our knowledge, not reported before. Three patient underwent surgical interventions and all received Itraconazol.

Case 1
A previously healthy 24 years old Saudi male presented with history of abdominal pain, diarrhea, intermittent fever and marked weight loss; 15 kg for four months, on physical examination he was chronically ill looking with normal vital signs and BMI of 21, he had tenderness in right iliac fossa with palpable tender hard and mobile mass. His laboratory testing showed WBC 14.4×10 3 uL −1 with 22% eosinophilia, Hg 7.1gm dL −1 , HCT 22.3%, MCV 55.3fL, MCH 17.3pg and platelet 1008×10 3 uL −1 , other laboratory testing include renal and liver function tests were normal apart from reduced albumin level 2.9 g dL −1 and ESR 130 mm h −1 . CT of the abdomen with contrast showed large bowel wall thickening seen in the cecum, ascending and transverse colon with involvement of the terminal ileum and multiple mesenteric lymph node enlargement Fig.1a-c, Colonoscopy showed deformed cecum with incompetent ileocecal valve with severe ulceration and nodularity of the distal part of terminal ileum and cecum with polypoidal mass at distal part of ascending colon Fig. 2a.
Colonoscopic biopsies showed heavily infiltrated tissue by an acute and chronic inflammatory cells with nonspecific features to suggest either tuberculosis or crohn's disease, an open extended right hemicoloectomy was done Fig. 3a and b and the mass specimen examined histopathologiclly which showed features of granulomatous inflammation with tissue eosinophilia along with presence of fungal hyphae throughout the tissue that stained positively with GMS stain Fig. 4. Sabouraud dextrose agar for the surgical specimen grew B. ranarum. The patient did well postoperatively and was treated with Itraconazole for 1 year and he is asymptomatic.

Case 2
Previously healthy 21 years old Saudi female presented with abdominal pain mainly in the left lower quadrant, diarrhea alternate with constipation, intermittent fever and marked weight loss; 20 kilograms for eight months, on examination of this lady, she was ill looking patient with BMI of 11.49 and normal vital signs. She had generalized abdominal distension and tenderness in left iliac fossa without any palpable masses, her laboratory workup at presentation showed WBC 7×10 3 uL −1 no eosinophilia, Hgb 8 g dL −1 , HCT 27.6%, MCV 65.7fL, MCH 20.5pg, Plt 800×10 3 uL −1 , ESR 100 mm h −1 , Creatinine 0.2 mg dL −1 , K 3.1 mmol L −1 , Na 132 mmol L −1 , Albumin 1.4 g dL −1 , Total Protein 6.6g dL −1 and normal liver enzymes. CT of the abdomen with contrast showed hugely dilated colon from the cecum till the rectum measuring 8 cm with circumfential wall thickening of the recto-sigmoid junction and mildly infiltrated fat planes Fig. 1d and e.     Colonoscopy showed inflammation, ulcerations and polypoidal lesions in sigmoid colon. Initial colonoscopic biopsies showed heavily infiltrated tissues by an acute and chronic inflammatory cells in the lamina propria with granulation tissue formation and vague collections of histocytes among which an occasional multinucleated giant cells were identified, there was crypt distortion, cryptitis and mucin depletion. After rolling out TB by culturing the tissue she was started on steroid with initial clinical improvement. Two weeks later, she presented again with deterioration of her symptoms and was started on TPN, at that time she had a generalized abdominal tenderness without guarding or rigidity and her lab work showed WBC 8.19×10 3 uL −1 no eosinophilia, Hgb 9.3 g dL −1 , HCT 28.9%, MCV 68.3fL, MCH 22pg, Plt 1115×10 3 uL −1 , Creatinine 0.4 mg dL −1 , K 3.1 mmol L −1 , Na 137 mmol L −1 , Total Protein 4.4 g dL −1 , Albumin 0.6 g dL −1 and ESR 140 mm h −1 . Colonoscopy showed worsening of the pervious lesions, deep ulcerations and more polypoidal lesions Fig. 2c and d. Colonoscopic biopsies for both histopathology and fungal culture showed presence of fungal hyphae, granulomatous inflammation and intense tissue eosinophilia with positive culture growth of B. ranarum Fig. 4. She was started on Itraconazole but she died as her condition was advanced and complicated by repeated hospital acquired infections and severe malnutrition.

Case 3
A previously healthy 72 years old Saudi male was referred to our hospital with history of abdominal mass and intermittent fever for one month, no history of abdominal pain, bleeding per rectum or weight loss, upon examination he was ill looking patient with BMI of 26.2 and normal vital signs. He had palpable hard tender mass in the left iliac fossa measuring 10×15 cm in diameter.
Laboratory workup showed WBC 15.28×10 3 uL no eosinophilia, Hgb 10.6 g dL −1 , HCT 30%, MCV 69.6fL, MCH 24.6pg, Plt 426×10 3 uL, ESR 95 mm h −1 , Creatinine 0.9 mg dL −1 , K 3.3 mmol L −1 , Na 142 mmol L −1 , Total Protein 5.9 g dL −1 , Albumin 1.8 g dL −1 and normal liver enzymes, CT abdomen with contrast showed three masses at the cecum, splenic flexure and the largest one in sigmoid colon with mesenteric lymph nodes enlargement. Colonoscopy showed fungating masses with bleeding ulcers at the cecum, descending and sigmoid colon. The histopathology for colonoscopic biopsies showed fragments of non-neoplastic tissues with granulation Science Publications AJID tissue formation and reactive inflammatory and hyperplastic changes. The patient underwent total colectomy, during surgery a huge three masses at cecum, sigmoid colon and splenic flexure were noted, the mass in splenic flexure was invading the surrounding structure with small perforation and thick pus discharge. After meticulous and difficult dissection a total colectomy performed with ilio-rectal primary anastomosis, the specimen sent for histopathology and cultures. The patient was diagnosed to have GI basidiobolomycosis based on identification of the fungus by culture Fig. 5b-d and the presence of fungal hyphea in the tissues with characteristic eosinophilic infiltration and he was started on Itraconazole. On day 25 post-operatively there was fecal discharge from lower part of the incision with guarding abdomen for that the Patient underwent explorative laparotomy which surprisingly showed five perforations at different sites; two perforations were managed by resection and primary anastomosis and the other three were repaired primarily in tow layer fashion. The patient condition complicated by ARDS and died on day 32 postoperative period from severe septic shock.

Case 4
A previously healthy 19 year old Saudi male was referred from peripheral hospital as case of abdominal masses for further workup and management. The patient was admitted there complaining of right iliac fossa pain for 3 months associated with fever, at that time he underwent emergency appendectomy for suspected appendicitis, during surgery irregular yellowish right pelvic mass with adherent omentum and loops of small intestine was noted along with minute perforation with small amount of thick pus collection, explorative laparotomy was done and intraoperatively an inflamed appendix was removed and the mass was biopsied. The histopathology showed many eosinophilic and multinucleated giant cells infiltration of the specimen associated with fat necrosis and granulomatous inflammation. On examination in our hospital he was ill looking patient and had BMI of 12.6 with normal vital signs, two clean abdominal incisions, no palpable masses or any evidence of peritonitis. The laboratory investigations showed WBC 22×10 3 uL −1 6.6% eosinophilia, Hgb 10.1 g dL −1 , HCT 30.5%, MCV 65.8fL, MCH 21.9pg, Plt 385×10 3 uL −1 , Creatinine 0.5 mg dL −1 , K 3.1 mmol L −1 , Na 136.7 mmol L −1 , ESR 80 mm h −1 , Total Protein 6.3 g dL −1 , Albumen 2.5 g dL −1 and normal liver enzymes. CT of the abdomen with contrast showed diffuse wall thickening of small and large bowel loops which were mottled together with smudged fat planes, minimal fluid collection and large para-aortic heterogeneous mass measuring 3×7 cm. Colonoscopy sowed severe edema from rectum till the descending colon with severe narrowing at 30 cm from anal verge at which the gastroenterologist could not introduce the scope farther. Biopsies from that mass were taken under CT guidance which were consistent with fungal mass with typical granulomatous inflammation and eosinophilic infiltration with presence of fungal hyphae throughout the tissue. The culture for the biopsied tissue grew B. ranarum. Subsequently, the patient was started on Itraconazol. After 15 days postoperatively there was fecal matter discharge from the lower end of the mid line incision, repeated CT of the abdomen showed enterocutaneous connection Fig. 5A. The patient underwent laparotomy, during surgery multiple enteroenteric, enterocolic and enterocutaneous fistula were noted and extensive adhesions between bowel loops with big perforation in rectosigmoid area, resection and anastomosis of small bowel and closure of perforation site by Hartmann's procedure (surgical resection of the rectosigmoid colon with closure of the rectal stump and formation of an end colostomy) was done. Postoperatively the patient was admitted to ICU and started on TPN but died due to repeated in hospital infections and ARDS.

DISCUSSION
Gastrointestinal basidiobolomycosis is a rare infection caused by the fungus Basidiobolusranarum, of the order Entomophthorales, it was first isolated in 1955 from decaying plants in the United States and subsequently has been found in soil and vegetations throughout the world. Although the histological features of B. ranarum are well described in the skin and subcutaneous tissue (Kwon-Chung and Bennett, 1992), gastrointestinal involvement has presented considerable diagnostic difficulties and confusion because of nonspecific presenting signs and symptoms along with that there is no identifiable risk factors (Sugar, 2004) and observantly the causative agent lies deep beneath the mucosa. So, colonoscopic biopsies may be nonrepresentative.
It may masquerade as other clinical entities (Khan et al., 1998) delaying definitive diagnosis and treatment with more morbidity and mortality. However, it should be suspected in the differential diagnosis of any GI mass with subacute onset of symptoms including abdominal pain, fever and loss of weight with or without eosinophilia.

Science Publications
AJID GIB may be emerging as a result of various environmental and demographic factors, all of our cases were from the same region (southern part of Saudi Arabia) which characterized by warm and humid climate (Jarie et al., 2003), which is a good environment for fungal growth and common presence of some species of reptiles specially wall lizards which found to be one species of reptiles that have B. ranarum in their GI tract and assumed to be the cause in one of the reported cases, the ingestion of soil or animal excreta or food contaminated by either are the most believable route of infection in such cases. The current experience of treating patients is limited; however, it seems that early diagnosis is crucial along with surgical resection of the infected tissue and prolonged treatment with Itraconazole offering the best chance for curing this disease.

CONCLUSION
Diagnosis of GIB requires high index of suspicion, increased awareness of this rare disease help reach an early diagnosis and prompt starting treatment. The clinical features of which resemble those of inflammatory or neoplastic bowel disease. Whenever these diagnoses are entertained, basidiobolomycosis might be considered in the differential diagnosis.

ACKNOWLEDGMENT
The researchers would like to thank Dr. Sabah N. Nemri, histopathology department, Aseer central hospital and Dr. Mohamed E. Hamid, clinical microbiology and parasitology department, King Khalid University for reviewing the histopathology slides and cultures results and for their valuable help.