Discussion
Kikuchi-Fujimoto disease (KFD) is a histiocytic necrotizing lymphadenitis, which was described in 1972 by Kikuchi and Fujimoto in Japan.2 KFD is a rare and benign disease with unknown etiology.4 Although the etiology of disease is still unclear, viral infections (Epstein-Barr virus, Cytomegalovirus, rhinovirus, rubella virus, and HIV) 5 and autoimmune diseases (SLE, Polymyositis, Rheumatoid arthritis, Still’s disease, and Sjogren’s syndrome)6 are proposed as possible triggers for KFD.
The most common clinical presentations of KFD are lymphadenopathy (79-94%), fever (35-67%), cutaneous rashes (4-32.9%), arthralgia (7-34.1%) and hepatosplenomegaly (3-14.8%).2 Less common presentations, including arthritis, weight loss, loss of appetite, hepatosplenomegaly, and sweating.4 Our patient experienced lymphadenopathy, fevers, night sweats, myalgia, weight loss and hair loss. The most frequent laboratory findings of KFD are elevated levels of ESR (78.9%), CRP (38.3%) and LDH (52.5-81.5%).2 Moreover, the literature has reported lymphopenia (63.8%), thrombocytopenia (5.4-19%) and leukocytosis (2-5%) in patients.2,5 Our patient had leukopenia, severe anemia, elevated LDH, raised ESR and CRP. The common presentations and remarkable laboratory changes, probably valuable along with excisional biopsy as a gold standard of diagnosis.
The diagnosis of KFD is based on histopathologic examination of an involved lymph node biopsy.1,4 The most common histologic finding is the presence of areas of necrosis and apoptosis which surrounded by CD68+ histiocytes, CD123+ plasmacytoid dendritic cells and activated CD8+ T-lymphocytes.7 Also, absence of neutrophils and eosinophils is an important characteristic in support of the diagnosis.5,8 Several studies purposed that KFD may be a clinical presentation of lupus lymphadenitis or associated with infectious mononucleosis-like syndromes such as EBV infection.2,5,6 Therefore, a complete work-up, including precise clinical examination with an excisional biopsy is recommended to rule out other serious autoimmune and infectious disease.
The long-term prognosis of KFD is good and deaths have been seen in a few patients with systemic forms of the disease.6,8KFD usually resolves within 1-6 months with a 12.2% recurrence rate in children.1,6 No specific treatment is known for KFD and the most common approach is supportive therapy.2,4NSAIDs are used to relieve some of the localized signs and symptoms such as fever and tenderness of lymph nodes. In severs forms of the disease patients maybe benefit from corticosteroid therapy, hydroxychloroquine or intravenous immunoglobulin.4,8
To our best knowledge, this is the first reported case of KFD, who was affected by COVID-19. Although the association of KFD and COVID-19 cannot be confirmed in this case, considering some cutaneous manifestations of COVID-19, such condition should not be missed.