A clinicopathological study of pulmonary mucormycosis in cancer patients: extensive angioinvasion but limited inflammatory response.

OBJECTIVES

Pulmonary mucormycosis (PMM) is an emerging, frequently lethal fungal infection in immunosuppressed cancer patients. We sought to characterize the histopathologic features of PMM in this population.

METHODS

We identified patients with PMM who underwent autopsy or lung biopsy between 1990 and 2007. Histopathology slides were blindly reviewed by a pathologist and findings were scored on standardized forms. Pathologic findings were correlated with demographic and clinical data abstracted from patient's medical records.

RESULTS

Twenty patients with PMM were included in this study. Nineteen patients (95%) had hematologic malignancies. High frequencies of angioinvasion (100%), hemorrhagic infarction (90%), coagulative necrosis (85%), and intra-alveolar hemorrhage (85%) were observed, whereas inflammatory infiltrates were uncommon (30%). Neutropenic patients had more extensive angioinvasion compared with non-neutropenic patients (77% versus 29%, P=0.06). Allogeneic hematopoietic stem cell transplantation (HSCT) recipients, all of whom had graft-versus-host disease, had more inflammatory cell infiltration but less intra-alveolar hemorrhage than non-HSCT patients (67% versus 14%, P=0.04; 50% versus 100%, P=0.02, respectively).

CONCLUSIONS

PMM in immunocompromised cancer patients is characterized by extensive angioinvasion and coagulative necrosis. The different histopathologic features of PMM in neutropenic, non-neutropnic, and HSCT patients may reflect differences in the pathobiology of PMM in these populations.