Letter to the Editor: Mimic of Malignancy: Gastric Mucormycosis Related to Use of a Supplement

To the Editor:

Mucormycosis is a rare, life-threatening invasive fungal infection that requires rapid diagnosis and treatment because of its high mortality rate. Isolated gastrointestinal mucormycosis is extremely rare, and it has been reported previously in the literature [1]; there have been no reports of relation with mitragynine. This supplement, better known as kratom, is a derivative of the evergreen tree Mitragyna speciosa and is known in the Western world for its use in pain relief and opioid withdrawal [2]. Unfortunately, it is also prone to contamination by fungi because of the lack of U.S. Food and Drug Administration regulation and quality standards and therefore can serve as the vector for invasive mucormycosis in immunocompromised individuals.

We recently treated a 65-year-old male with diabetes mellitus with severe epigastric abdominal pain, constipation, and unintentional weight loss of 35 pounds over a one-month period. Computed tomography (CT) revealed a hypodense 3.3 × 2.3 cm lesion invading the posterior wall of the greater curvature of the proximal gastric body with associated wall thickening. Clinically, our differential diagnosis was malignancy versus penetrating gastric ulcer.

Esophagogastroduodenoscopy was performed with findings of a 4 cm ulcerated infiltrative mass on the proximal greater curvature of the stomach 5 cm distal to the gastroesophageal junction. Biopsy of this lesion confirmed the presence of Zygomyces with no evidence of malignancy. On further evaluation, our patient noted that he had been taking the supplement kratom for his chronic back pain in lieu of opioids. Antifungal treatment was initiated and considering the literature supporting aggressive debridement [3], we concluded that resection was essential to survival. Our patient underwent an open subtotal gastrectomy with Roux-en-Y reconstruction. Operative findings were significant for a contained perforation of the posterior wall of the stomach into the tail of the pancreas. Final pathology revealed degenerated fundal hyphae consistent with zygomycetes within fibrinopurulent exudate on methenamine silver (GMS) stain, concordant with our diagnosis of mucormycosis (Fig. 1). There was no evidence of underlying malignancy, and all margins were negative. Our patient did well post-operatively and was treated with amphotericin B for two weeks, followed by a prolonged course of posaconazole.

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FIG. 1.

Gastric biopsy with mucosal necrosis and degenerated fundal hyphae consistent with zygomycetes within fibrinopurulent exudate without angioinvasion.

The diagnosis of mucormycosis is delayed in many cases because of its rarity, leading to poor outcomes resulting from the angioinvasive nature of the organism. Immunocompromised patients including those with diabetes mellitus, neutropenia, malignancies, autoimmune disorders, organ transplants, steroid use, and iron overload states are particularly at risk for infection [4]. These may be members of the same patient population who are likely to search for alternative pain remedies, such as kratom. As a plant-derived supplement, its components are sensitive to the traditional methods of decontamination and therefore ripe for cross-contamination by a variety of microbes. In cases of visceral disease, malignancy must be ruled out expediently to avoid morbidity and mortality caused by misdiagnosis. With the increasing stringency in regard to prescription narcotics in the United States, alternative supplements have become more commercialized, and providers should be particularly aware of the use of alternative pain supplements, such as kratom, as potential sources of invasive fungal infections.