Positron emission tomography/computed tomography hypermetabolism of Kikuchi-Fujimoto disease mimicking malignant lymphoma: a case report and literature review

Abstract

Kikuchi-Fujimoto disease (KFD), also known as histiocytic necrotizing lymphadenitis, is a benign, self-limiting inflammatory disorder of unknown etiology and pathogenesis. This report presents a rare case involving a man with ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) hypermetabolism caused by KFD mimicking malignant lymphoma. The PET/CT maximum intensity projection showed multiple hypermetabolic lymphadenopathies and homogeneous FDG uptake in the bone marrow and spleen. Malignant lymphoma was initially suspected. The patient then underwent excision biopsy of one enlarged right cervical lymph node that was selected because it showed the highest FDG uptake in PET/CT, and examination of this biopsy specimen confirmed the diagnosis of KFD. PET/CT is useful for assessing the general condition of patients and can help to select lymph nodes for excision biopsy based on the highest FDG uptake. However, KFD can predispose to localized FDG uptake and limit the specificity of PET/CT by mimicking malignancy. Thus, positive results of PET/CT should be interpreted with caution.

Keywords: Kikuchi–Fujimoto disease; Positron emission tomography/computed tomography; case report; fluorodeoxyglucose; lymphadenopathy; lymphoma.

Figure 1.

Whole-body PET/CT scan findings. (a) The MIP image showed intense accumulation of FDG in the lymph nodes. (b)–(f) PET/CT fusion images showed multiple areas of hypermetabolic lymphadenopathy in the bilateral cervical, right supraclavicular, bilateral axillary, abdominal, and bilateral inguinal lymph nodes (white arrowhead). (g), (h) PET/CT fusion images showed mild, homogeneous FDG uptake in the spleen and bone marrow of the vertebral bodies.

Figure 2.

Histopathological examination. Histopathologic examination of a lymph node specimen showed numerous lymphohistiocytic cells and karyorrhectic debris (hematoxylin and eosin stain; magnification, ×100).