Microscopic sclerosing angiomatoid nodular transformation (SANT) in an accessory spleen or splenunculus

摘要

A 63-year old male underwent a distal pancreatectomy and splenec-tomy for a solid, slowly enlarging pancreatic nodule. Associated with the pancreatic tail but separate to the spleen several lymph nodes were also sampled. The pancreatic lesion was confirmed to be a completely excised serous cystadenoma. The spleen was normal and one of the sampled "lymph nodes" was in fact, an accessory spleen or splenunculus. The splenunculus measured 0.8 x 0.5 x 0.3 cm and grossly appeared uniformly tan in colour. Microscopic evaluation of the splenunculus revealed a 0.4 x 0.3 cm well circumscribed nodule that was clearly demarcated from the rest of the accessory splenic parenchyma. It consisted of a myriad of blood-filled slit-like vascular channels. Within the centre of the lesion a sclerotic, fibrous focus containing similar blood vessels was also noted. The cellular component of ovoid and spindle cells lining the vascular spaces were positive for CD31, CD34 (highlighting a reticular vascular network) and negative for CD8, CD21 and CD68. These features were in keeping with a microscopic sclerosing angiomatoid nodular transformation occurring within an accessory spleen or splenunculus.