| Abstract|| |
Mucormycosis is caused by fungi of the order Mucorales and class Zygomycetes. It is a rare opportunistic infection frequently associated with immunocompromised status. It can be disseminated disease or localized, which includes rhinocerebral, pulomonary, cutaneous, and gastrointestinal mucormycosis. Gastrointestinal mucormycosis is the most uncommon usually fatal disease accounting for 4–7% of all cases. We present a rare case of unusual presentation of angioinvasive colonic mucormycosis in a seemingly immunocompetent female masquerading as inflammatory bowel disease. It is very important to differentiate between both because treatment with steroids may lead to dissemination of disease ultimately resulting in a fatal outcome. A surgeon should maintain a high index of suspicion as timely appropriate surgical intervention along with effective antifungal treatment remains the cornerstone of treatment for this highly fatal disease. The definitive diagnosis is possible only by histopathological demonstration of tissue invasion. This requires a quantitatively and qualitatively adequate tissue biopsy.
Keywords: Angioinvasion, gastrointestinal mucormycosis, immunocompetent, inflammatory bowel disease, surgical intervention
|How to cite this article:|
Shankaralingappa S. Unsuspected invasive gastrointestinal mucormycosis masquerading as inflammatory bowel disease: A pathologist's perspective. Indian J Pathol Microbiol 2019;62:332-4
|How to cite this URL:|
Shankaralingappa S. Unsuspected invasive gastrointestinal mucormycosis masquerading as inflammatory bowel disease: A pathologist's perspective. Indian J Pathol Microbiol [serial online] 2019 [cited 2020 Jun 2];62:332-4. Available from: http://www.ijpmonline.org/text.asp?2019/62/2/332/255811
| Introduction|| |
Mucormycosis is a rare opportunistic infection caused by fungi of the order Mucorales and class Zygomycetes. They are ubiquitous saprophytic fungi which inhabit soil and dead and decaying organic matter. This disease in humans is frequently associated with predisposing risk factors such as diabetes mellitus, neutropenia, immune deficiencies, malignancy, bone marrow transplantation, prolonged use of antibiotics, and corticosteroid therapy. Other contributing host risk factors include acidotic state, malnutrition, trauma, and iron overload.,,,, In the past, gastrointestinal mucormycosis was diagnosed primarily in premature neonates presenting as necrotizing enterocolitis. However in recent years, this deadly disease has been diagnosed in adults without traditional risk factors.,,
The fungus exists in two forms, infective sporangiospores and the hyphal form, which causes tissue necrosis and dissemination. Gastrointestinal mucormycosis may present as a primary infection, in which case the disease is acquired through ingestion of contaminated material or as a secondary infection in disseminated mucormycosis through metastatic spread by mycotic emboli. Angioinvasion causes vascular thrombosis and ischemic tissue necrosis.,,
It is a rapidly progressive fatal disease and 50% of the cases are diagnosed post mortem., Lack of specific clinical, endoscopic, and radiological features leads to delay in diagnosis. A vigilant gastrointestinal surgeon should maintain a high index of suspicion as survival of these patients is dependent on early diagnosis, prompt surgical treatment, removal of predisposing risk factors, and effective antifungal therapy.
| Case Report|| |
A nondiabetic 59-year-old female presented with diarrhoea and melena. She had nausea, vomiting, and decreased appetite, not associated with fever. She gave a history of haemorrhoidectomy done ten years back. Her systemic examination was normal and blood pressure was 120/80 mmHg. Her investigations revealed haemoglobin of 7.3 g/dl (12–15.5 g/dl), albumin 1.5 g/dl (3.5–5.2 g/dl), serum folic acid >23 ng/ml (3–20 ng/ml), iron 12 μg/dl (45–182 μg/dl), total iron binding capacity 151 μg/dl (261–478 μg/dl), transferrin saturation 39.7% (12–55%), and ferritin 478 ng/ml (11–307 ng/ml). She was treated for nutritional anemia, transfused PRBC, and given intravenous iron.
Colonoscopy showed severely inflamed rectum and left colon with multiple ulcers. Amoebic serology was negative. Contract computed tomography (CT) showed pancolitis with diffuse mucosal avid enhancement in the arterial phase, submucosal edema, maximum wall thickness of 10 mm in transverse colon [Figure 1], and increased vascularity in colonic mesentery. Changes of sacroileitis were also noted. Initial biopsy showed features of active colitis. All these features could not preclude from making the diagnosis of inflammatory bowel disease. She was treated with antibiotics and discharged on the ninth day with oral prednisolone 40 mg OD.
|Figure 1: Resected segment of transverse colon. Inset: Axial view of contrast CT abdomen showing mild diffuse wall thickening of transverse colon with abnormal mucosal enhancement|
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On 16th day she presented with severe vomiting, distension of abdomen, pedal edema, and disorientation with BP of 70/60 mmHg. Her investigations revealed hyponatremia, metabolic acidosis, and hypoxemia. Her total white blood cell count was 39,000/cumm (4,000–11,000/cumm) with 95% neutrophils, serum creatinine 2.12 mg/dl (0.6–1.2 mg/dl), urea 52 mg/dl (17–43 mg/dl), free T4 22.7 pmol/l (10.3–29.6 pmol/l), TSH 0.21 mIU/ml (0.34–5.6 mIU/ml), total bilirubin 6.19 mg/dl (0.3–1.2 mg/dl), SGOT 582 U/l (<35 U/L), SGPT 66 U/l (<35 U/l), ALP 878 U/l (42–98 U/l), and GGT 792 U/l (<38 U/l). Bilateral lung fields showed ground glass appearance with dense basal consolidation and pleural effusion.
CT abdomen showed pneumoperitoneum, suggestive of bowel perforation. Emergency exploratory laparotomy was performed. Resected segment of ileum and transverse colon [Figure 1] showed gangrenous changes, pericolic prominent vasculature, and mucosal ulcers. Microscopic examination revealed gangrenous and necroinflammatory changes with patchy destruction of colonic mucosa in transverse colon, dense infiltration of acute inflammatory cells in the ulcerated areas, microabscesses in all layers of bowel wall, and clumps of pauci-septate, unevenly wide hyphae having wide angled branching [Figure 2]. These features were highlighted on periodic acid Schiff (PAS) and Gomori's methanamine silver (GMS) stains [Figure 2]. Angioinvasion and thrombus formation was seen in submucosal, subserosal, and pericolic mesenteric vasculature. The patient died due to multiorgan failure and septic shock on the 22nd day (second postoperative day).
|Figure 2: Microphotograph showing broad pauciseptate hyphae invading the muscularis externa (H and E, ×40). Inset: Fungal hyphae highlighted in GMS stain, ×10|
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| Discussion|| |
Gastrointestinal mucormycosis is the rarest manifestation of mucormycosis accounting for 4–7% of all cases. Stomach is the most common site (57.5%) involved and is accompanied by 92% mortality rate. This is followed by colon (32.3%) and ileum (6.9%). Tissue infarction and angioinvasion is seen in 94% of the sampled tissue, as in our case.,
Although tissue diagnosis in our case was made only in colon and terminal ileum, multiorgan pathology suggests that infection was not limited to gastrointestinal tract, but involved lungs, kidne, and endocrine organs (low TSH and free T4 on higher side). Presence of vomiting aided by radiological finding of mild diffuse wall thickening of antrum and pyloric region of stomach suggests probable involvement of stomach.
In the past, most cases of gastrointestinal mucormycosis have been reported in adults with some degree of immunocompromised status. However, cases have been reported in patients without underlying traditional risk factors in recent years.,, In our case, although patient did not have major risk factors, she had anemia of chronic disease with high serum ferritin indicating increased tissue iron stores and was also malnourished with low serum albumin levels. Fungi scavenge free iron from host and their interaction determine the rate of replication and survival in vivo.,
Lack of clinical suspicion led to delay in diagnosis in our case. In addition, lack of specific radiological and endoscopic findings along with inadequate tissue biopsy led to the diagnosis of inflammatory bowel disease. Moreover, inadvertent administration of steroids and iron injection in an already malnourished female might have aggravated the disease leading to a fatal outcome. Hence, in a seemingly immunocompetent individual presenting with severe inflammatory colitis mimicking inflammatory bowel disease, gastrointestinal mucormycosis should be considered in differential diagnosis and should be ruled out before treating for inflammatory bowel disease. When associated with hypoalbuminemia, malnutrition, and anemia of chronic disease, surgeon should maintain a high index of suspicion and perform timely diagnostic evaluation and surgical intervention to improve patient outcome. Our case also highlights the importance of adequate tissue biopsies to facilitate early and prompt diagnosis as this is very critical in this deadly disease.
| Conclusion|| |
Invasive gastrointestinal mucormycosis can be seen in individuals with hypoalbuminemia/malnutrition and anemia of chronic disease having some degree of immunocompromised status. They can mimic inflammatory bowel disease clinically and radiologically. Knowing these unusual presentations, a vigilant surgeon should maintain high index of suspicion as early prompt diagnosis and appropriate timely surgical intervention is the key to reduce rapid fatal outcome associated with this disease. Further, demonstration of tissue invasion by adequate tissue biopsies is the cornerstone for prompt diagnosis of this deadly disease.
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Department of Pathology, Columbia Asia Hospital, Hebbal, Bengaluru - 560 024, Karnataka
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2]