Kikuchi-Fujimoto disease and acute appendicitis

Abstract

A 29-year-old Japanese man developed fever, nausea, vomiting, diarrhoea, right lower quadrant abdominal pain and rebound tenderness. With the clinical suspicion of appendicitis, an abdominal CT scan was performed, which revealed mesenteric lymphadenitis. The patient was hospitalised and treated with antibiotics, but was ultimately found to have Kikuchi-Fujimoto disease (KFD). This diagnosis was facilitated by the use of positron emission tomography scan that identified an accessible inguinal lymph node for biopsy and histopathological evaluation. Invasive abdominal surgery was thereby averted and the patient made a complete recovery on subsequent follow-up. Review of the published literature reveals that pseudoappendicitis due to KFD is a rare occurrence that has generally required abdominal surgery to establish the diagnosis, thus supporting the potential value of the approach taken here.

Figure 1

Abdominal CT scan with contrast (A) and ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) scan of mesenteric lymph nodes (B) cluster of hypermetabolic lymph nodes seen in the bowel mesentery along the right colic distribution of the superior mesenteric artery to the level of the caecum.

Figure 2

CT scan with contrast (A) and ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) scan (B) of left inguinal node—left inguinal node seen on CT scan is identified as hypermetabolic on PET scan.

Figure 3

H&E staining/CD68 immunohistochemical staining of excised lymph node. (A) Inguinal lymph node (H&E; ×2). Necrotising changes are centred in the subcapsular regions. They appear focal and well circumscribed. (B) Inguinal lymph node (H&E ×40). Crescentic histiocytes (yellow arrow) with areas of wide cytoplasm, others with eccentric nuclei (green arrow). (C) Lymph node CD68 immunohistochemical staining. The histiocytes in the karyorrhectic foci are positive for the CD68 antigen.