*Department of Pathology, Fudan University Shanghai Cancer Center †Department of Oncology, Shanghai Medical College, Fudan University, Shanghai §Department of Pathology, Xijing Hospital and School of Basic Medicine, the Fourth Military Medical University, Xi'an, China ‡Department of Pathology, Queen Elizabeth Hospital ∥Department of Pathology, Queen Mary Hospital, Hong Kong ¶Diagnostic Medlab #Department of Molecular Medicine and Pathology, University of Auckland, Auckland **Department of Surgery, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.
Am J Surg Pathol. 2014 May;38(5):646-53. doi: 10.1097/PAS.0000000000000170.
Inflammatory pseudotumor-like follicular dendritic cell (FDC) tumor is an uncommon, Epstein-Barr virus-associated neoplasm of the liver or spleen, characterized by spindly tumor cells dispersed in a background of small lymphocytes and plasma cells. We report 6 diagnostically challenging cases in which the neoplastic component is further overshadowed by granulomas or eosinophils. The patients included 2 men and 4 women with a median age of 45.5 years, and 1 of them showed concurrent involvement of the liver and spleen. The presence of extensive coalescent epithelioid granulomas in 3 splenic tumors and 3 liver tumors raised the possibilities of an infective process or sarcoidosis. In another liver tumor, the massive infiltrate of eosinophils, accompanied by geographic eosinophilic abscesses, suggested parasitic infestation or so-called eosinophilic granuloma of the liver. However, scrutiny of the tissue between the granulomas or among the eosinophils revealed scattered atypical spindly cells with indistinct cell borders, large vesicular nuclei, and distinct nucleoli. The atypical cells were positive for FDC markers on immunostaining (CD21, CD35) and Epstein-Barr virus on in situ hybridization. Thus, a diagnosis of inflammatory pseudotumor-like FDC tumor could be confirmed. Awareness of the granulomatous and eosinophil-rich variants of this tumor type will facilitate the correct diagnosis to be made.
炎性假瘤样滤泡树突细胞（FDC）肿瘤是一种罕见的、与 EBV 相关的肝或脾肿瘤，其特征为梭形肿瘤细胞散布在小淋巴细胞和浆细胞背景中。我们报告了 6 例具有诊断挑战性的病例，其中肿瘤成分进一步被肉芽肿或嗜酸性粒细胞所掩盖。这些患者包括 2 名男性和 4 名女性，中位年龄为 45.5 岁，其中 1 例同时累及肝和脾。3 个脾脏肿瘤和 3 个肝脏肿瘤中广泛融合的上皮样肉芽肿的存在，增加了感染过程或类肉瘤病的可能性。在另一个肝脏肿瘤中，大量嗜酸性粒细胞浸润，伴有局灶性嗜酸性脓肿，提示寄生虫感染或所谓的肝嗜酸性肉芽肿。然而，仔细观察肉芽肿之间或嗜酸性粒细胞之间的组织，发现散布着散在的、非典型的梭形细胞，细胞边界不清晰，细胞核大而泡状，核仁明显。这些非典型细胞在免疫染色（CD21、CD35）和原位杂交上均为 FDC 标志物阳性，EB 病毒阳性。因此，可以确诊为炎性假瘤样 FDC 肿瘤。了解这种肿瘤类型的肉芽肿和嗜酸性粒细胞丰富的变体将有助于正确诊断。
