Abstract:
CASE 1: A 65-year old man was diagnosed with acute myeloblastic leukemia (AML) and was treated with an intensive chemotherapeutic regimen. During induction phase, the patient developed pulmonary mucormycosis. This diagnosis was made thanks to CT scan and bronchoalveolar lavage. An antifungal therapy (AFT) with liposomal amphotericin B and posaconazole was started. After 4 months of AFT, a second CT scan was realized showing a residual lung lesion. This lesion was excavated and localized in the superior lobe of the left lung (24x14x15 mm). A 18FDG-PET/CT did not show any metabolic activity of this lesion (Suv max 1.2), highlighting that it was residual and allowing the end of AFT. A surgical resection of this lesion was performed. Interestingly, its histological exam did not show any fungus but cicatricial lesion with fibrosis. Unfortunately, the patient relapsed of the AML and died. CASE 2: A 28-year old man was diagnosed as having a B-cell acute lymphoblastic leukemia (ALL) CD20+ Ph1- and received intensive chemotherapy. During the treatment, the patient displayed a multisystemic invasive fungal disease (IFD) involving lungs, liver, lymph nodes, spleen and kidneys. The histological exam of a hepatic abscess and a lymph node found mold elements, but they were too altered to make a more precise diagnosis. An AFT with liposomal amphotericin B and posaconazole was started. 18FDG-PET/CTs were performed at 5, 6 and 14 months of AFT in order to monitor its efficacy. The first one shew multiple hypermetabolic foci; all of them disappeared on the last one. Thanks to that, AFT was stopped after 19 months without recurrence of IFD. DISCUSSION: About 50-70% of febrile neutropenias are considered as « fevers of unknown origin » (FUO). A growing number of studies highlight the role of 18FDG-PET/CT in the diagnosis of IFD in neutropenic and non-neutropenic patients. Moreover, recent studies also show a role of this imaging in the therapeutic monitoring of neutropenic and non-neutropenic patients with IFD. Therefore, in the future, 18FDG-PET/CT could be used in hematology, both in the neutropenic and non-neutropenic settings, in order to reduce the duration of AFT which may be toxic and expensive.
