In 5 of the 7 previous cases of pancreatic FDCS, both CD21 and CD23 were expressed, which is useful for distinguishing it from other diseases such as cross-dendritic cell sarcoma (IDCS), Langerhans cell sarcoma (LCS), and histiosarcoma (HS) [16]. The gene discussed is CR2; the disease is Langerhans cell sarcoma.