Successful Treatment of Cutaneous Mucormycosis Disseminated from Pulmonary Mucormycosis with Liposomal Amphotericin B and Posaconazole
Mucormycosis is a rare but severe opportunistic infection caused by fungi within the class Zygomycetes and the order Mucorales. It predominantly affects immunocompromised individuals, such as those with hematologic malignancies, diabetes mellitus, or organ transplants. The infection can manifest in various forms, including pulmonary, cutaneous, rhinocerebral, and disseminated mucormycosis. Disseminated mucormycosis, which occurs in approximately 23% of cases, is associated with a nearly 100% mortality rate. This article presents a detailed case study of a 52-year-old man with acute lymphoblastic leukemia who developed disseminated mucormycosis, initially presenting as a pulmonary infection that later spread to the skin. The successful treatment of this patient with liposomal amphotericin B and posaconazole underscores the importance of early diagnosis and aggressive antifungal therapy.
The patient, a 52-year-old man with a two-year history of acute lymphoblastic leukemia, initially presented with a cough and expectoration two months prior to the current admission. Despite negative blood and lung tissue cultures, a positive serum 1,3-b-D-glucan assay and chest computed tomography (CT) findings of new exudation in the right lung led to a diagnosis of pulmonary fungal infection. Ten days before admission, the patient developed a fever and noticed a small, painful erythema on his right thigh. The lesion rapidly enlarged and ulcerated, prompting further evaluation.
Physical examination revealed a 2 cm by 4 cm ulcer with surrounding erythema and induration on the right thigh. The ulcer featured a necrotic eschar without purulent secretion or exudation. Histopathological examination of the lesion showed hyperplasia of the epidermis and dermal perivascular infiltration of lymphocytes, neutrophils, and plasma cells. Notably, thrombosis of blood vessels was observed in the dermis. Hematoxylin-eosin and periodic acid-Schiff (PAS) staining both revealed broad, non-septate hyphae with right-angle branching within the thrombi. Despite negative results from direct microscopy of the lesion and polymerase chain reaction (PCR) assay for mucormycosis in formalin-fixed paraffin-embedded tissue, the patient was diagnosed with disseminated mucormycosis based on the clinical history, physical examination, and histopathological findings.
The patient was treated with intravenous liposomal amphotericin B at a dose of 50 mg/day and posaconazole at 800 mg/day. After four weeks of treatment, a follow-up chest CT scan showed significant improvement in the pulmonary infection, and the skin ulcer had healed with crust formation. This case highlights the importance of considering mucormycosis in immunocompromised patients with unexplained skin lesions, particularly when there is a history of pulmonary infection.
Cutaneous mucormycosis typically presents as a necrotic eschar surrounded by erythema and induration, often accompanied by severe pain. Most cases result from the direct inoculation of fungal spores into the skin, with approximately 20% of these lesions later disseminating to other sites. However, hematogenous dissemination from other organs to the skin is rare, occurring in only about 3% of cases. In this patient, the absence of local trauma and the timing of the skin lesion following the exacerbation of pulmonary infection strongly suggested hematogenous dissemination from pulmonary mucormycosis.
Early diagnosis of mucormycosis is crucial for improving patient outcomes. Rapid identification of hyphae in clinical samples through direct microscopy is highly suggestive of the disease. Tissue culture and molecular identification can confirm the diagnosis, but these methods may yield false-negative results, as seen in this case. The negative lung tissue culture and PCR assay for mucormycosis in formalin-fixed paraffin-embedded tissue complicated the diagnosis, emphasizing the need for a high index of suspicion in immunocompromised patients with compatible clinical and histopathological findings.
The treatment of mucormycosis involves a combination of surgical debridement of infected tissues and antifungal therapy. Amphotericin B remains the first-line antifungal agent, with liposomal formulations preferred due to their reduced nephrotoxicity. Newer azoles, such as posaconazole and isavuconazole, are also effective and should be considered, particularly in cases of disseminated disease. In this patient, the combination of liposomal amphotericin B and posaconazole led to significant clinical improvement, demonstrating the efficacy of this therapeutic approach.
The successful treatment of this patient underscores the importance of recognizing skin manifestations as a potential early sign of disseminated mucormycosis. Early initiation of antifungal therapy, combined with surgical intervention when necessary, can significantly improve outcomes in this otherwise fatal disease. This case also highlights the challenges in diagnosing mucormycosis, particularly in immunocompromised patients with negative microbiological and molecular tests. A high index of suspicion, thorough clinical evaluation, and prompt initiation of appropriate therapy are essential for managing this life-threatening infection.
In conclusion, mucormycosis is a rare but serious fungal infection that predominantly affects immunocompromised individuals. Disseminated mucormycosis, particularly when it involves the skin, is associated with a high mortality rate. Early diagnosis and aggressive treatment with liposomal amphotericin B and posaconazole can lead to successful outcomes, as demonstrated in this case. Clinicians should maintain a high index of suspicion for mucormycosis in immunocompromised patients with unexplained skin lesions, especially when there is a history of pulmonary infection. Prompt recognition and appropriate management are crucial for improving survival in this challenging condition.
doi.org/10.1097/CM9.0000000000000891
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