title: Kikuchi-Fujimoto disease (histiocytic necrotizing lymphadenitis) with atypical encephalitis and painful testitis: a case report.
abstract: BACKGROUND
  Kikuchi-Fujimoto disease is a self-limited clinicopathologic entity that is increasingly recognized worldwide. Kikuchi-Fujimoto disease is characterized by cervical lymphadenopathy occurring in young adults. Neurologic involvement is rare, and testitis directly caused by Kikuchi-Fujimoto disease has not yet been reported.
  
  
  METHODS
  A 19-year-old man was brought to our clinic with complaints of fever, headache, fatigue, and left lower quadrant pain that had persisted for 3 weeks. On physical examination, painful cervical lymphadenopathies were observed. Meningitis was suspected based on a cerebrospinal fluid examination, and left-sided orchitis was diagnosed based on findings from magnetic resonance imaging and ultrasonography. However, neither antibiotics nor antiviral drugs were effective in treating the patient's symptoms. On the 20thday of hospitalization, the patient experienced a loss of consciousness, and brain T2-weighted magnetic resonance imaging showed asymmetrical, high-signal intensities in both basal nuclei and the left temporal lobe. Encephalitis was suspected, and the patient was treated with intravenous prednisolone pulse therapy (1 g/day) for 3 days and intravenous immunoglobulin therapy for 5 days. A left cervical lymph node biopsy showed apoptotic necrosis in paracortical and cortical areas with an abundance of macrophages and large lymphoid cells, which had irregular nuclei suggestive of Kikuchi-Fujimoto disease; the pathological findings from a brain biopsy were the same as those of the cervical lymph node biopsy. The encephalitis and cervical lymphadenopathies followed a benign course, as did the testitis.
  
  
  CONCLUSIONS
  This is the first report of Kikuchi-Fujimoto disease involving painful testitis and pathologically proven asymmetrical brain regions. Kikuchi-Fujimoto disease should be included in the differential diagnosis when a patient presents with encephalitis, testitis, and fever of unknown origin.
authors.affiliation: Department of General Medicine and Emergency Care, Toho University School of Medicine, 6-11-1 Omorinishi Ota-ku, Tokyo, 143-8541, Japan. hidenori775@gmail.com.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Kido
authors.affiliation: Division of Neurology, Department of Internal Medicine, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Kano
authors.affiliation: Department of General Medicine and Emergency Care, Toho University School of Medicine, 6-11-1 Omorinishi Ota-ku, Tokyo, 143-8541, Japan.
authors.forename: Asami
authors.initials: A
authors.lastname: Hamai
authors.affiliation: Department of Neurosurgery Radiology, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Masuda
authors.affiliation: Department of Neurosurgery Radiology, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Fuchinoue
authors.affiliation: Department of Neurosurgery Radiology, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Nemoto
authors.affiliation: Department of Otorhinolaryngology, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Chiaki
authors.initials: C
authors.lastname: Arai
authors.affiliation: Department of Otorhinolaryngology, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Teppei
authors.initials: T
authors.lastname: Takeda
authors.affiliation: Department of Urology, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Fumihito
authors.initials: F
authors.lastname: Yamabe
authors.affiliation: Department of Urology, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Tai
authors.affiliation: Department of Urology, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Mizuki
authors.initials: M
authors.lastname: Kasahara
authors.affiliation: Department of Radiology, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: Department of Radiology, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Shiraga
authors.affiliation: Department of Pathology, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Sota
authors.initials: S
authors.lastname: Sadamoto
authors.affiliation: Department of Pathology, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Wakayama
authors.affiliation: Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological, Tokyo, Japan.
authors.forename: Yukitoshi
authors.initials: Y
authors.lastname: Takahashi
authors.affiliation: Division of Neurology, Department of Internal Medicine, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Iwasaki
authors.affiliation: Department of Pathology, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Shibuya
authors.affiliation: Department of General Medicine and Emergency Care, Toho University School of Medicine, 6-11-1 Omorinishi Ota-ku, Tokyo, 143-8541, Japan.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Urita
mesh_terms: D000328:Adult; D004660:Encephalitis / Q000209:etiology*; D020042:Histiocytic Necrotizing Lymphadenitis / Q000150:complications*; D006801:Humans; D008297:Male; D010146:Pain / Q000209:etiology*; D013733:Testicular Diseases / Q000209:etiology*; D055815:Young Adult
keywords: Encephalitis; Fever of unknown origin; Histiocytic necrotizing lymphadenitis; Kikuchi-Fujimoto disease; Testitis