人類皰疹病毒第四型（Epstein-Barr virus, EBV）引起的單核球增多症在兒童並 不少見，主要症狀有發燒、咽扁桃腺炎和淋巴結腫大。然而，許多兒童一開始的臨床 表現並不典型因此需要臨床醫師審慎評估。EBV 會作用於淋巴單核細胞和內皮網狀系 統，故有些案例一開始的臨床檢查結果會和血液惡性疾病無法區分。另外，淋巴結腫 大的位置也可能導致不同的鑑別診斷。我們在此報告兩個初期表現類似其他疾病的單 核球增多症孩童案例。一位是其周邊血液學檢查呈現白血病之不成熟芽細胞，另一位 則是耳下腫大位置和腮腺炎無法區分的病例。兩位患者最後都因陽性病毒血清學檢查 而被診斷為EBV 感染之單核球增多症，經過支持性治療後皆順利出院。因此，臨床醫 師須對於EBV 感染所造成的多變臨床症狀及表現相當警覺，方能有正確診斷且避免不 必要的檢查或用藥。

Infectious mononucleosis caused by Epstein-Barr virus (EBV) infection is not rare in children. Fever, pharyngotonsilitis and lymphadenopathy are its major presentations. As the EBV mainly targets lymphomononuclear cells and the reticuloendothelial system of the body, some cases may initially be mistakenly diagnosed as leukemic malignancy. Moreover, the location of the swollen lymph nodes may also mislead during diagnosis. We report two children with infectious mononucleosis(IM) who had various initial manifestations that mimicked other diseases. One child presented with a large number of blast cells in a peripheral blood smear, which mimicked leukemia, while the other one had swollen masses within their bilateral subauricular regions, which mimicked mumps. Both children were finally diagnosed as having EBV-related infectious mononucleosis by positive serological testing and recovered after supportive care. A review of the literature regarding atypical presentation of IM is included. It is concluded that physicians should be alert to the various presentations of EBVrelated infectious mononucleosis so that they make a correct diagnosis, which will prevent unnecessary examinations and medication of the patient.