Ultrastructural Profile of Two Cases

Splenic hamartoma (SH) is a rare, benign lesion. We present 2 cases, both in females (2 and 30 years, respectively) with multiple urinary tract infections, and left upper quadrant abdominal pain. Immunohistochemical staining with factor VIII displayed intense diffuse staining in the SH with corresponding weak staining in the adjacent spleen. CD31 showed a reverse pattern from that of factor VIII. CD34 staining pat-tern was identical in both the spleen and the SH. Ultrastructurally, the SH showed en-dothelial cells with relatively empty cytoplasm, scattered Weibel Palade bodies, and lining by basement membrane surrounded by fibrous long-spacing collagen. Our study highlights the unique immunohistochemical profile of SH. The ultrastructural features are interesting, although their diagnostic significance remains to be con-firmed in future studies. Int J Surg Pathol 13(1):103-111, 2005 Key words: normal spleen, immunohistochemistry, electron microscopy. Splenic hamartomas (SH) are rare, benign le-sions, first discovered by Rokitansky in 1861. Only about 150 cases have been described in the English language literature. Splenic hamartoma is also known by several other terms: splenoma, splenade-noma, accessory spleen in spleen, nodular hyperplasia, fi-brosplenoma, and splenic splenunculus. These lesions are usually an incidental finding in otherwise asymptomatic patients. The availability of comput-erized topography (CT) scans and ultrasound may account for the corresponding increased reporting of cases. Herein, we present 2 cases of SH, 1 in a 30-year-old woman and the other in a 2-year-old child. The preoperative diagnostic evaluation of these lesions and the pathological evaluation including immunohis-tochemical (IHC) and ultrastructural (US) studies is discussed along with a review of the literature