Epstein-Barr virus-associated inflammatory pseudotumor of the spleen: report of two cases and review of the literature

Abstract

We report two rare examples of Epstein-Barr virus (EBV)-associated inflammatory pseudotumor of the spleen. One patient presented with night sweats, abdominal pain, and weight loss and was found to have a splenic mass on CT scan suspected of lymphoma. The splenic mass in second patient was found incidentally at the time of work up for kidney stones. The pathologic examination of these splenectomy specimens showed similar histologic features. However, the spindle cells were composed of EBV-infected follicular dendritic cells in one case whereas the second case lacked significant follicular dendritic cell proliferation and showed only focal EBV-infected cells suggesting that these proliferations are heterogenous in nature.

Fig. 1

CT scan of the abdomen in case 1 demonstrates a solitary 6 cm in greatest dimension solid appearing splenic mass

Fig. 2

Cut surface of the splenectomy specimen in case 1 demonstrates a well-circumscribed 6 cm in diameter fleshy mass with small foci of hemorrhage and necrosis

Fig. 3

Histologic section of splenic tumor in case 1 shows a mixed inflammatory infiltrate and a proliferation of spindle cells with storiform pattern. Hematoxylin and eosin stain, original magnification, × 200

Fig. 4

Immunohistochemical stain using anti-CD35 antibody in case 1 highlights foci of follicular dendritic cell proliferation. Immunoperoxidase stain, original magnification, × 200

Fig. 5

In situ hybridization using EBV-encoded small RNA probes demonstrates numerous EBV-infected cells including oval and spindle cells in case 1. Original magnification, × 200

Fig. 6

Histologic section of splenic mass in case 2 shows a mixed infiltrate including many mature appearing plasma cells and occasional oval and spindle cells. Hematoxylin and eosin stain, original magnification, × 200

Fig. 7

Immunohistochemical stain using anti-smooth muscle actin (SMA) antibody in case 2 highlights most oval and spindle cells. Immunoperoxidase stain, original magnification × 200

Fig. 8

In situ hybridization using EBV-encoded small RNA probes demonstrates focal weak EBV-positive cells in scattered oval to spindle cells in case 2. Original magnification, × 200