Contributed by Aaron Berg, MD
A maximum of 0.5 AMA PRA Category 1 Credits are available from a quiz on this case from the University of Pittsburgh's Internet-based Studies in Education and Research. Please review the case before taking the quiz.
The patient is a 44 year old female who was found to have an incidental heterogeneously enhancing splenic mass on CT scan. A follow up CT scan 2 years later demonstrated a solid appearing splenic mass with peripheral enhancement on the arterial phase and progressive enhancement on the portal venous phase. The size had increased from 1.6 cm to 2.9 cm so a splenectomy was performed.
The spleen grossly weighed 123 grams. Within the lower pole, there was a well circumscribed, red and tan, 3.1 x 2.7 x 2.2 cm mass which abutted the capsule. The remaining splenic parenchyma was unremarkable. (Figure 1)
The mass was well circumscribed and comprised of multiple proliferating vascular lobules separated by dense fibrous septations. The septations were collagenized with some myxoid matrix and occasional myofibroblasts and scattered inflammatory cells. The vascular lobules consisted of cleft-like spaces lined by plump, round to oval cells without any atypia, and were filled with many red blood cells and some inflammatory cells. No mitoses were identified. (Figures 2, 3 and 4)
IMMUNOHISTOCHEMICAL STAINS CD34 - highlighted many small vascular structures. (Figure 5)
CD8 - highlighted a few vascular structures. (Figure 6)
CD31 - highlighted many small vascular structures, including the CD34 positive and CD8 positive structures, as well as other cells in the structures. (Figure 7)
CD68 - highlighted numerous positive cells
ALK - negative
CD21 - negative
IgG4 - negative
Bartonella - negative
HHV8 - negative
EBV - negative