A rare case of an EBV-positive inflammatory follicular dendritic cell tumor of the spleen

Abstract

Epstein-Barr virus positive inflammatory pseudotumor follicular dendritic cell sarcoma (EBV+ FDCS) is a rare indolent neoplasm that presents primarily in the spleen and liver. We display a case of EBV+ FDCS in the spleen, its clinic-pathologic properties, and treatment. Our patient was evaluated following an incidental finding of a splenic mass on imaging after a traumatic injury. Computed tomography and magnetic resonance imaging both confirmed a well-circumscribed lesion in the spleen. Consequently, the patient underwent a robotic-assisted diagnostic splenectomy. Histologic examination revealed portions of spleen with partial effacement of tissue architecture by a well-circumscribed nonencapsulated mass displaying atypical, spindled cells-positive for EBER (CISH), EBV LMP1, smooth muscle actin, and clusterin-mixed inflammatory elements, and interspersed small lymphocytes.

Keywords: EBV; inflammatory follicular dendritic cell tumor; spleen.

Figure 1

Computed tomography of the abdomen and pelvis with contrast showing an indeterminate round 3.5 cm hypo-attenuating lesion in the spleen: (a) axial and (b) coronal views with arrow marking the mass.

Figure 2

Magnetic resonance imaging of the abdomen with contrast showing a well-circumscribed 3.7 × 3.7 cm solid lesion in the lower pole of the spleen with a decreased signal on T2 on (a) axial and (b) coronal views with arrow marking the mass.

Figure 3

A well-circumscribed, nonencapsulated mass displaying mixed inflammatory elements (hematoxylin & eosin 40X).

Figure 4

Variably increased stromal/spindled cells were noted (hematoxylin & eosin 400X).

Figure 5

An atypical, spindled population is highlighted by CISH for EBER (EBER in situ hybridization 400X).

Figure 6

Atypical, spindled population is highlighted by clusterin (Clusterin 400X).