title: Inflammatory pseudotumor-like follicular dendritic cell tumor of liver and spleen: granulomatous and eosinophil-rich variants mimicking inflammatory or infective lesions.
abstract: 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.
authors: *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.
authors: Xiao-Qiu
authors: XQ
authors: Li
authors: Wah
authors: W
authors: Cheuk
authors: Polly W Y
authors: PW
authors: Lam
authors: Zhe
authors: Z
authors: Wang
authors: Florence
authors: F
authors: Loong
authors: Mee-Ling
authors: ML
authors: Yeong
authors: Peter
authors: P
authors: Browett
authors: John
authors: J
authors: McCall
authors: John K C
authors: JK
authors: Chan
mesh_terms: D000328:Adult; D020566:Dendritic Cells, Follicular / Q000473:pathology*; D004804:Eosinophils / Q000473:pathology; D020031:Epstein-Barr Virus Infections / Q000150:complications / Q000473:pathology*; D005260:Female; D006104:Granuloma, Plasma Cell / Q000473:pathology* / Q000821:virology; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008107:Liver Diseases / Q000473:pathology* / Q000821:virology; D008297:Male; D008875:Middle Aged; D013158:Splenic Diseases / Q000473:pathology* / Q000821:virology