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Invasive Cutaneous Mucormycosis in a Patient With Chronic Lymphocytic Leukemia on Obinutuzumab, Idelalisib, and Bruton Tyrosine Kinase Degrader: A Case Report

Summary

A 74-year-old man with leukemia developed a serious fungal infection (mucormycosis) on his ankle while taking cancer-fighting drugs. The infection was diagnosed through tissue biopsy examination rather than standard culture tests. Treatment required both powerful antifungal medications and surgical removal of the infected leg below the knee. The patient recovered successfully after this aggressive treatment approach.

Background

Invasive fungal infections due to Mucorales are significant infectious complications in patients with hematologic malignancy with high mortality rates. New targeted biologic therapies used in cancer treatment have variable effects on the innate and humoral immune system, potentially increasing infection risk. This case describes a rare presentation of invasive cutaneous mucormycosis in a patient on multiple novel targeted therapies for chronic lymphocytic leukemia.

Objective

To present a case of invasive cutaneous mucormycosis in an elderly patient with chronic lymphocytic leukemia receiving combination targeted biologic therapy and to highlight diagnostic challenges and management considerations for this serious infection.

Results

Histopathology revealed broad aseptate fungal hyphae with angioinvasion pathognomonic for cutaneous mucormycosis, while tissue cultures and fungal NGS were negative. Extensive necrosis of fascia, muscle, and tendons necessitated limb amputation below the knee for definitive source control. The patient achieved clinical cure with clear surgical margins confirmed on histopathology and remained stable on isavuconazole therapy discontinued six weeks post-surgery.

Conclusion

This is the first reported case of invasive cutaneous mucormycosis in a CLL patient on newer targeted biologic agents including BTK degrader, obinutuzumab, and idelalisib. Early diagnosis via histopathology, prompt antifungal initiation, and aggressive surgical source control are essential for clinical cure. Further study is needed on infectious risks associated with newer targeted biologic therapies.
  • Published in:Cureus,
  • Study Type:Case Report,
  • Source: PMID: 41133038, DOI: 10.7759/cureus.92967
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