Indian Journal of Pathology and Microbiology

: 2020  |  Volume : 63  |  Issue : 2  |  Page : 322--324

Colonic malakoplakia in a cardiac transplant recipient: A case report

Sadiya Shafijan 
 Consultant, SRM Institute for Medical Sciences Chennai, Tamil Nadu, India

Correspondence Address:
Sadiya Shafijan
Flat No T-1, Ameer Regency, No 21, Balaji Nagar, 2nd Street, Royapettah, Chennai, Tamil Nadu - 600 014

How to cite this article:
Shafijan S. Colonic malakoplakia in a cardiac transplant recipient: A case report.Indian J Pathol Microbiol 2020;63:322-324

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Shafijan S. Colonic malakoplakia in a cardiac transplant recipient: A case report. Indian J Pathol Microbiol [serial online] 2020 [cited 2020 Jul 12 ];63:322-324
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Malakoplakia is a rare inflammatory condition which is usually seen in the urogenital tract and less commonly in the gastrointestinal tract. Gastrointestinal malakoplakia may be associated with organ transplantation. There are previously only three reported cases of malakoplakia in cardiac transplant recipient. We report a case of colonic malakoplakia in a 38-year-old male who underwent cardiac transplantation for dilated cardiomyopathy. Although rare, malakoplakia may be associated with chronic diarrhea even if there are no macroscopic lesions seen during colonoscopy.

Gastrointestinal malakoplakia is observed in association with a variety of conditions such as ulcerative colitis, diverticular disease, adenomatous polyp, carcinoma, and immunodeficiency.[1] Malakoplakia has been rarely reported in the setting of liver and kidney transplantation.

A 38-year-old male had received a cardiac transplant four years previously for severe heart failure due to dilated cardiomyopathy. He had been on treatment with triple immunosuppression for 6 months with prednisolone, tacrolimus, and mycophenolate, followed by dual immunosuppression with tacrolimus and cellcept. He was on regular follow-up for 5 years until he presented with a 6-month history of diarrhea associated with fecal incontinence. Upper gastrointestinal endoscopy was normal and deep duodenal biopsy done to exclude protozoal and helminthic infections was also normal. Ileocolonoscopic examination was done and the mucosa of ileum and colon was colonoscopically normal. Rectal biopsies were taken to exclude microscopic pathology.

Gross examination showed three gray-brown fragments of soft tissue each measuring 0.3 cm. Microscopy revealed an unremarkable epithelium. The lamina propria showed infiltration by histiocytes with granular eosinophilic cytoplasm admixed with a few lymphocytes and plasma cells [Figure 1] and [Figure 2]. Many histiocytes had several rounded basophilic structures of approximately 1 to 10 μm in size with the characteristic morphology of Michaelis–Gutmann bodies showing a laminated dense central core with a targetoid appearance [Figure 3]. These Michaelis–Gutmann bodies were stained with Periodic acid Schiff's stain (PAS) [Figure 4]a and were resistant to diastase (PAS-D). They were also stained for calcium on Von Kossa stain [Figure 4]b. There was no intranuclear cytoplasmic inclusion suggestive of viral cytopathy. Gram stain, acid-fast stain, and Perl's Prussian blue stain for iron were all negative. A diagnosis of malakoplakia was considered and the patient was treated with ciprofloxacin. At review 1 month later, the patient did not have diarrhea.{Figure 1}{Figure 2}{Figure 3}{Figure 4}

Malakoplakia involving the colorectum is a possible consequence of immunosuppression following transplantation. Although a small number of case reports suggests that this is a rare complication, the one account of a fortuitous diagnosis in a post-transplant recipient with normal colonoscopy highlights the rarity. The gastrointestinal tract is the second most commonly involved system by malakoplakia and in most cases, the disease involves the colon and rectum. It may be clinically silent or may present with diarrhea, abdominal pain, hemorrhage, and obstruction.[2] Colonic involvement can be segmental or diffuse.

Histological findings are pathognomonic and establish the diagnosis of malakoplakia. Microscopically malakoplakia of the gastrointestinal tract must be differentiated from Whipple's disease, tuberculosis, especially atypical mycobacteria, other infectious and noninfectious granulomas and fungal infections, especially histoplasmosis. The negativity for Gram stain, acid-fast stain, and fungal stain (GMS) ruled out the possibility of Whipples disease, atypical mycobacteriosis, and fungal infection. The positivity for PAS, PAS diastase, and Von Kossa confirmed the diagnosis of malakoplakia. Perl's Prussian blue stain may show variable positivity.

Escherichia coli is the most common associated bacterial pathogen in 90% of affected patients. An abnormal immune response (e.g., immunosuppression used to prevent rejection in organ transplant patients) and abnormal lysosome function within macrophages is implicated in the pathogenesis.

Malakoplakia of colon has been described in post-transplant patients. Review of the literature revealed only 4 cases previously reported in kidney transplant recipients from 1994 to 2010.[3] Other transplant-associated colonic malakoplakia included three cases with liver transplants[4] and 3 cases of colonic malakoplakia in cardiac transplant patients.[5] All patients in the reported cases presented with diarrhea, abdominal pain, fever, and/or intestinal perforation. The sites of involvement are perianal region, rectum, ileo-caecum, ascending, transverse, and descending colon. Colonoscopic examination revealed polypoidal nodules, mass forming depressed lesions, oedematous mucosa with loss of vascular pattern, and patchy erythema. Our case was unique in showing a normal colonoscopic mucosal examination. Transplant recipient patients are at risk of malakoplakia, the graft itself or other sites may be involved. Colby et al.[6] have reported two cases of pulmonary malakoplakia in a cardiac transplant recipient with the isolated bacterial pathogens being Corynebacterium and Acinetobacter spp.

Attempts at the treatment of malakoplakia have included two main approaches: the administration of cholinergic agonist to improve the macrophage function and long-term antibiotic therapy. A dramatic reduction of immunosuppressive medication is often a necessary component of medical treatment of malakoplakia in this setting. We present this case to sensitize readers to the possibility of malakoplakia as a cause of post-transplant diarrhea even if the mucosal appearance is normal.

Although varying colonoscopic appearances are seen in colonic malakoplakia in transplant recipient patients, our case is unique in its presentation in view of its normal colonoscopic examination. Although rare, malakoplakia is one of the potential causes of diarrhea in patients with organ transplantation. It is a benign self-limited condition that responds to antibiotic therapy and to the reduction of immunosuppression. Our case may serve as a reminder of the clinical significance of malakoplakia with a normal colonoscopic pattern in a cardiac transplant patient.

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