Mucormycosis is caused by environmental molds belonging to the order Mucorales, most notoriously the genus Rhizopus, whose spores float freely in soil, decaying organic matter, and damp air. In most people, inhaled spores are simply engulfed and destroyed by neutrophils and macrophages, the innate immune cells that patrol the airways. But when those defenses falter, as in diabetes, cancer, or organ transplantation, the spores germinate into broad, ribbon-like fungal hyphae that invade blood vessels with terrifying speed. This angioinvasion triggers thrombosis and tissue death, driving a fulminant infection that kills 40 to 50 percent of affected patients even with treatment. Diabetes remains the most common predisposing factor, associated with an overall mortality of roughly 46 percent, and more than half of all mucormycosis cases in large reviews occur in people with overt immunosuppression.

The Iranian patient’s initial symptoms were strikingly atypical, which is precisely why the diagnosis proved so treacherous. He complained of severe right-sided epigastric pain and excessive watering of the right eye, with no nasal congestion, no fever, and no neurological signs. His doctor prescribed topical ketorolac eye drops for presumed conjunctivitis. Instead of improving, he deteriorated: marked redness around the eye progressed to bruising-like ecchymosis and swelling, prompting admission to Prophet Azam Hospital at Kerman University of Medical Sciences. The authors of the report suggest that the abdominal pain may have reflected inadvertent ingestion of fungal spores, since gastrointestinal acquisition of Mucorales is well documented and greenhouse workers handle contaminated material constantly, though it may equally have been an incidental finding that contributed to the dangerous delay.

On admission, the man was alert, oriented, and afebrile, with intact vision and no cranial nerve deficits, findings that could easily have reassured clinicians. But computed tomography and magnetic resonance imaging of his sinuses and orbits told a more alarming story: right-sided proptosis, meaning the eye was being pushed forward, together with significant edema and infiltration of both the intraconal and extraconal fat spaces inside the orbit. T2-weighted MRI sequences showed the bright signal characteristic of acute inflammatory change, though without definite evidence of intracranial extension or cavernous sinus thrombosis. Such imaging findings are non-specific and can appear in severe bacterial cellulitis, but the combination of rapid deterioration, extensive orbital involvement, and the patient’s occupational history in a high-risk environment raised immediate suspicion of invasive fungal disease and guided the urgent biopsy that followed.

The laboratory work-up was equally revealing for what it did not find. The patient’s white blood cell count was mildly elevated at 12.6 × 10³ per microliter with 95 percent neutrophils, C-reactive protein stood at 37 mg/L, and his erythrocyte sedimentation rate was 21 mm/h, all consistent with a robust systemic inflammatory response. Yet targeted immunological testing, including HbA1c of 5.3 percent, negative HIV serology, and normal immunoglobulin G, A, and M levels, confirmed that he was genuinely immunocompetent. His fasting glucose of 110 mg/dL represented only an impaired fasting glucose, a subtle metabolic derangement. The authors note that even mild hyperglycemia can upregulate endothelial receptors such as GRP78, enhancing fungal adhesion and angioinvasion, and emerging evidence suggests that transient or subclinical dysglycemia can predispose otherwise healthy individuals to opportunistic mycoses.

Definitive diagnosis came from the mycology laboratory. During drainage of the eye discharge, necrotic tissue and purulent secretions were sampled and examined under potassium hydroxide preparation, hematoxylin and eosin staining, and Giemsa staining. All three revealed the pathognomonic signature of Mucorales: broad, aseptate, ribbon-like hyphae branching at wide angles. Culture on Sabouraud dextrose agar produced luxuriant, fluffy, grayish-white to brown colonies within seven days at 30 degrees Celsius, and lactophenol cotton blue microscopy of the isolate, showing sporangiophores with rhizoids at their base and a columella, identified the culprit as a Rhizopus species. Repeat sampling from the skull base again yielded positive results. Critically, treatment was initiated on the basis of microscopy alone, because fungal culture sensitivity is only 30 to 50 percent and its slow turnaround makes it useless for guiding urgent therapy.

What followed was an aggressive multimodal assault on the infection. Surgeons performed an urgent orbital exenteration, the radical removal of the entire contents of the eye socket, after intraoperative inspection revealed extensive necrotic tissue that had to be excised to prevent extension to the skull base, a complication carrying a mortality above 80 percent. Simultaneously, the patient received intravenous liposomal amphotericin B at 5.0 to 10 mg/kg per day, continued for a total of three weeks. The combined medical-surgical approach was well tolerated and produced a favorable clinical response. He was discharged in stable condition upon completing the antifungal course, and final culture results corroborated the diagnosis seven days after discharge. At follow-up three months later, he remained asymptomatic with no signs of recurrence, though he has been counseled on occupational safety measures should he return to greenhouse work.

The case fits a growing pattern in which occupational and environmental exposure, rather than host immunosuppression, precipitates invasive disease. A cohort study of cucumber greenhouse workers documented substantial exposure to airborne fungi, including Mucorales species, using next-generation sequencing alongside biomarkers of systemic inflammation, lending biological plausibility to the exposure route even though invasive disease was not observed in that cohort. Comparable risk has been described after natural disasters, including a case of rhino-orbital mucormycosis in an immunocompetent adult following prolonged mold exposure during post-hurricane cleanup, and rural living or contact with organic matter has been implicated in pediatric orbital mucormycosis without underlying immunodeficiency. The authors argue that a sufficiently high inoculum of spores can simply overwhelm innate defenses, particularly phagocytosis by neutrophils and macrophages, which are typically effective against Mucorales.

A literature search across PubMed, Scopus, and Web of Science covering January 2000 to October 2025, summarized by the authors, shows how consistently diagnostic delay haunts immunocompetent patients. A 67-year-old woman who developed headache, diplopia, and vision loss after post-hurricane mold cleanup recovered fully after multiple debridements and amphotericin B. A 12-year-old girl with a nasal foreign body and Rhizopus oryzae infection survived after surgery and antifungal therapy, as did a 22-year-old man with a minor skin lesion who required exenteration. But a 59-year-old woman with no identified risk factors died of multiple organ failure, diagnosed only at post-mortem, and a 32-year-old man died after treatment non-compliance, a reminder that even favorable biology depends on adherence to therapy. Across these reports, the absence of classic risk factors and the non-specific nature of early symptoms repeatedly misled clinicians.

For physicians on the front lines, the message is stark: progressive orbital infections deserve consideration of mucormycosis even in patients with no diabetes, no malignancy, and no immunosuppressive drugs, particularly when their work or environment involves soil, decaying vegetation, or mold-laden air. Interestingly, angioinvasion in immunocompetent hosts may follow a somewhat less fulminant course than in diabetic patients, offering a window for recovery if clinicians act quickly. High clinical suspicion, prompt histopathological diagnosis using KOH preparations and tissue staining, and aggressive combined surgical and antifungal treatment remain the pillars of survival, with combined approaches yielding roughly 60 percent survival in rhino-orbital-cerebral disease compared with more than 90 percent mortality in disseminated infection. As greenhouse agriculture expands worldwide, this single case suggests that the boundary between harmless environmental mold and life-threatening invasion may be thinner than the immune status of the host alone would suggest.

Subject of Research: Rhino-orbital mucormycosis in an immunocompetent adult linked to occupational greenhouse mold exposure

Article Title: Rhino‐Orbital Mucormycosis in an Immunocompetent Adult: A Case Report Emphasizing Diagnostic and Therapeutic Challenges

Article References: Mousavi, S. M., Mousavi, S. A. A., Faryabi, O., Sharifi, I., Kamyab, H., & Shirazi, Z. (2026). Rhino‐Orbital Mucormycosis in an Immunocompetent Adult: A Case Report Emphasizing Diagnostic and Therapeutic Challenges. Clinical Case Reports, 14(10), Article e73683. https://doi.org/10.1002/ccr3.73683

Image Credits: AI Generated

DOI: 10.1002/ccr3.73683

Keywords: mucormycosis, Rhizopus, orbital exenteration, immunocompetent patient, greenhouse workers, occupational exposure, liposomal amphotericin B, fungal infection, angioinvasion, diagnostic delay, Mucorales, Iran