Intra-abdominal Mucormycosis in an Immunocompetent Host: A Rare Presentation and Literature Review

Abstract

Mucormycosis is a severe, opportunistic infection caused by Mucorales, a taxonomical group of thermotolerant fungi primarily affecting the immunocompromised. Intra-abdominal involvement in mucormycosis is a rare entity, particularly in immunocompetent individuals. We present a fatal case of gallbladder and renal mucormycosis in an immunocompetent female, leading to septic shock and death. The diagnosis was confirmed via histopathology following cholecystectomy for suspected gangrenous cholecystitis and open right nephrectomy due to kidney infarction. Quantitative polymerase chain reaction of the tissue identified the presence of Apophysomyces ossiformis. The clinical picture was confounded by ongoing sepsis due to a Klebsiella pneumoniae-infected retroperitoneal hematoma, non-specific imaging findings, and the absence of traditional risk factors for mucormycosis, leading to a delayed diagnosis. Despite surgical debridement, initiation of liposomal amphotericin B with posaconazole, and aggressive treatment in the intensive care unit, the patient succumbed to complications of mucormycosis. Despite adequate antibiotic coverage, this case underscores the importance of considering Mucorales infection in otherwise immunocompetent patients with a deteriorating clinical condition. Early diagnosis and appropriate intervention are essential in enhancing mucormycosis survivability, though mortality rates remain high in severe cases.

Keywords: apophysomyces ossiformis; diagnostic challenges; gallbladder mucormycosis; liposomal amphotericin b; renal mucormycosis; septic shock.

Figure 1. Endoscopic images of the lower gastrointestinal tract.

Colonoscopy images are shown. (A) In the region of the splenic flexure, a 3-cm submucosal lesion was noted. (B) At around 5 cm distal to the first lesion, there was another 3 cm lesion with an umbilicated center. Arrows are included to highlight the submucosal lesions in the figures.

Figure 2. Computed tomography with and without contrast showing large retroperitoneal fluid collection.

Anterior to the aorta and vena cava and posterior to the transverse duodenum there is a large bilobed fluid collection, which also abuts the descending colon. The fluid collection measures approximately 14.3 cm transversely and 5.5 cm anteroposteriorly. On imaging, the fluid collection appears to be denser than water. Image shown is contrast enhanced.

Figure 3. Computed tomography of the abdomen showing developing infarction of right kidney.

The right kidney is enlarged with a large area of non-enhancement in the superior pole consistent with infarction. This scan is eight days following the computed tomography scan shown in Figure 2, which did not show any right kidney infarction. Retroperitoneal drain is present and can be seen exiting the site of the infected retroperitoneal hematoma, with evidence of fluid reduction and interval improvement. (A) Coronal and (B) axial views are shown to demonstrate the extent of infarction. Arrows in the figure point to the right kidney and area of infarction in both views.

Figure 4. Computed tomography of the abdomen showing complete infarct of the right kidney.

Abdominal imaging was repeated four days after the computed tomography scan in Figure 3. There is interval development of a complete right kidney infarction. (A) Coronal view demonstrating the complete right kidney infarction and the enlarged size of the right kidney (14 cm x 7 cm). (B) Axial view demonstrating the complete renal infarction. Arrow is included, pointing to the infarcted right kidney.

Figure 5. Computed tomography of the abdomen showing interval development of gangrenous cholecystitis.

There is interval development of curvilinear membranes within the gallbladder concerning for gangrenous cholecystitis. (A) Coronal and (B) axial views are shown. Arrows are included in both views to highlight the gallbladder with curvilinear membrane development.

Figure 6. Gallbladder tissue histopathology images obtained following laparoscopic cholecystectomy.

(A) A low power view of the gallbladder is shown. There is significant inflammation with abundant acute and chronic inflammation. The center of the image shows a small artery with necrotic changes. (B) A medium power view of the artery with necrotic changes is shown. (C) A high-power view with fungal elements, including broad and ribbon-like hyphae with inconspicuous septations and some branching is shown. (D) Grocott’s Methenamine Silver stain of the tissue is shown. Arrows are included in the figure to highlight the fungal elements.