Disseminated Cunninghamella bertholletiae mucormycosis with protracted clinical course and formation of a large intra-ventricular mural thrombus.

We report the autopsy findings of a case of disseminated mucormycosis caused by Cunninghamella bertholletiae, a rare pathogenic fungus of the family Mucoraceae. The patient was a 49-year-old woman with B-lymphoblastic leukemia with hyperdiploidy, who died of progressive heart failure 4 months after induction chemotherapy successfully brought about complete remission of the leukemia. Granulocyte colony-stimulating factor (G-CSF) had been administered along with anti-neoplastic drugs, and her blood neutrophil count was markedly elevated. Autopsy revealed disseminated mycotic thromboembolism and abscess formation in the heart, lung, liver, kidney, and spleen. The most marked feature was a large mural thrombus in the left ventricle containing numerous fungal hyphae. In the myocardium and disseminated foci in visceral organs, giant cell-rich, fibrotic reactions to the mycotic infection were observed. Both the formation of a large intra-ventricular mural thrombus and giant cell reactions are rare findings in mucormycosis. We considered that the recovery and marked increase in neutrophil count induced by chemotherapy and G-CSF administration prolonged the clinical course and pathologically elicited an atypical, giant cell reaction to the mycotic infection. The prolonged clinical course also contributed to the formation of an unusually large intra-ventricular mural thrombus.