Splenic Inflammatory Pseudotumor-Like Follicular Dendritic Cell Tumor

Abstract

Inflammatory pseudotumor of the spleen with expression of follicular dendritic cell markers is an extremely rare lesion with only a few cases reported previously. The present study reports on an inflammatory pseudotumor of the spleen 10 × 8 × 7 cm in size that was incidentally found in a 61-year-old man and increased gradually in size during a period of 3 months. Abdominal ultrasonography revealed a well-circumscribed splenic mass, and abdominal computed tomography confirmed the presence of a well-circumscribed isodense lesion in the splenic hilum with inhomogenous enhancement in the early-phase images and no enhancement on delayed-phase contrast-enhanced images. Magnetic resonance imaging of the abdomen showed a well-defined isodense tumor on T1-weighted images with mildly increased signal intensity on T2-weighted images, and this is only the second study that provides MRI findings of this entity. The patient underwent an uncomplicated open splenectomy for definitive histologic diagnosis. Under microscopic examination, the lesion was an admixture of lymphocytes, plasma cells and spindle cells. In situ hybridization analysis for Epstein-Barr virus (EBV) revealed that most of the spindle cells were positive for EBV, and immunochemistry showed the expression of the follicular dendritic cell markers CD21, CD35 and CD23 within the tumor. The diagnosis of inflammatory pseudotumor-like follicular dendritic cell tumor was established.

Clinicopathological features of inflammatory pseudotumour‐like follicular dendritic cell tumour of the abdomen

“…To date, 44 cases of inflammatory pseudotumour-like FDC tumour have been reported in the English-language literature. [3][4][5][6][7][8][9][10][11][12] In contrast to the female predilection reported in the literature, 2,6,11 the tumour predominantly affected males (male.female ratio of 2.3:1) in our series. The difference might be attributable to the small number of cases and different regions.…”

“…Inflammatory pseudotumour‐like FDC tumour is a rare variant of FDC tumour. To date, 44 cases of inflammatory pseudotumour‐like FDC tumour have been reported in the English‐language literature . In contrast to the female predilection reported in the literature, the tumour predominantly affected males (male.female ratio of 2.3:1) in our series.…”

Inflammatory pseudotumor-like follicular dendritic cell tumor: an underdiagnosed neoplasia

“…From 1996 to date we retrieved 22 publications reporting IPT-like FDC tumors [11,15,35,[89][90][91][92][93][94][95][96][97][98][99][100][101][102][103][104][105][106][107]. There were 46 patients described: 24 female, 22 male (ratio 1.1:1), median age 57y (range 29-79y).…”

Splenic Epstein-Barr Virus–Associated Inflammatory Pseudotumor

“…21 The background lymphocytes in EBV-associated IPT are predominantly CD3 þ T cells, admixed with fewer CD20 þ B cells. [4][5][6]9,11,12,16,19 Choe et al 8 reported a series of 6 cases of IPT-like FDC tumor with markedly increased immunoglobulin (Ig) G4-positive plasma cells ranging from 27 to 128 cells per high-power field. The ratio of IgG4-positive cells to IgG-positive cells in these cases was 25% to 75%.…”

“…To date, 32 cases of splenic IPTlike FDC tumor have been reported in the English-language literature. 1,[4][5][6][7][8][9][10][11][12][13][14][15][16] Very rare cases of IPT-like FDC tumor have been reported outside the spleen or liver. 4,17 Inflammatory pseudotumor-like FDC tumor differs from conventional FDC sarcoma by almost exclusive localization in spleen and liver, frequent presence of systemic symptoms, indolent clinical behavior, an IPT-like appearance, and consistent association with EBV.…”