Utility of Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Patients with Visceral Leishmaniasis: Case Report and Literature Review

Abstract

The diagnosis of visceral leishmaniasis (VL) is complicated and often unsuspected. Little is known of the usefulness of nuclear imaging in VL. Our objective was to describe findings seen in fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in cases of VL. We retrospectively reviewed VL cases diagnosed at Vall d’Hebron University Hospital from May 2012 to May 2018 and selected those that had an FDG-PET/CT performed. Information on procedures and details of the FDG-PET/CT features and follow-up were collected. We then systematically reviewed the literature on VL and FDG-PET/CT. Four of 43 patients diagnosed with VL had an FDG-PET/CT performed. All four patients presented diffuse splenic uptake of FDG-PET/CT. Adenopathy was not always present, and bone marrow uptake was found in two patients. A posttreatment FDG-PET/CT in one patient revealed normalization of initial findings. In the literature review, 43 of 50 cases presented similar splenic uptake in the PET/CT, being described as different patterns: “increased metabolism,” “homogeneous,” “diffuse,” “diffuse and multifocal,” “nodular,” “patchy and granular,” “subcortical,” and “compatible with lymphoma.” Other frequent findings were bone marrow uptake and adenopathies. We, therefore, conclude that FDG-PET/CT could become a useful tool for the diagnosis and follow-up of VL and that VL should be taken into account in patients with fever of unknown origin with enhanced splenic uptake in FDG-PET/CT. Differential diagnosis in these cases should be made with splenic primary lymphoma, virus infections, chemotherapy, and colony-stimulating factor therapy. Further structured studies with more cases are needed to define its diagnostic and prognostic value.

Clinical and laboratory characteristics of hemophagocytic lymphohistiocytosis induced by Leishmania infantum infection

“…Thus, iron overload with hepatosplenomegaly detected in this study may reflect the severe conditions in the Leishmania infection and its associated HLH. Several studies have demonstrated the pattern of Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (F18 FDG-PET/CT) in the visceral leishmaniasis [27][28][29]. Diffuse splenic and bone marrow uptake of FDG is the main feature in the VL patients, and VL associated HLH cases presented more significantly elevated diffuse uptake in the liver, spleen and spinal column.…”

Case Report: FDG-PET/CT findings in co-infection of visceral leishmaniasis and chronic hepatitis B

“…PET/CT is valuable in the diagnosis of fever of unknown origin, but there is little information on the diagnosis potential of FDG-PET/CT in VL, especially in immunocompromised patients. PET/CT shows that most VL patients had increased spleen FDG uptake, and some patients have bone marrow and lymph node FDG uptake ( Pinnegar et al., 2021 ). Bone marrow and lymph node uptake are more likely to occur in immunocompetent patients than in immunocompromised patients ( Pinnegar et al., 2021 ).…”

“…PET/CT shows that most VL patients had increased spleen FDG uptake, and some patients have bone marrow and lymph node FDG uptake ( Pinnegar et al., 2021 ). Bone marrow and lymph node uptake are more likely to occur in immunocompetent patients than in immunocompromised patients ( Pinnegar et al., 2021 ). Two different patterns of spleen FDG uptake in VL patients have been defined on PET/CT examination: diffuse and focal ( Zanoni et al., 2019 ).…”

“…Furthermore, VL has a longer incubation period in mostly HIV-positive and solid organ transplant patients, which even shows Leishmania detected by atypical locations other than the spleen, liver, or bone marrow ( Pinnegar et al., 2021 ). It was previously reported that an immunosuppressed patient presented an incubation period of VL over 15 years, and his PET/CT showed enhanced uptake throughout the colon, spleen, liver, lymph nodes, and lungs ( Rinaldi et al., 2019 ).…”

“…Some patients are referred for a PET/CT scan for unknown fever. However, VL has been mostly misdiagnosed as lymphoma by nuclear medicine physicians due to the lack of systemic understanding in the past ( Pinnegar et al., 2021 ). Thus far, only a few cases of VL complicating with other infections have been reported by PET/CT.…”