Indolent T-lymphoblastic proliferation associated with Castleman disease and low grade follicular dendric cell sarcoma: report of a case and review of literature.

Indolent T-lymphoblastic proliferation (IT-LBP) is referred to as extrathymic immature TDT+T-cell hyperplasia, non-neoplastic lesion, often misdiagnosed as T-lymphoblastic lymphoma and overtreated. We report a case of a 20-year-old male patient with a right adrenal gland mass, diagnosed as indolent T-lymphoblastic proliferation (IT-LBP) associated with hyaline vascular Castleman disease (HV-CD) and low grade follicular dendric cell sarcoma (LG-FDCS). The case is a rare combination of finding, and it is the first case occurring in adrenal gland. IT-LBP is a clinically indolent disease, requiring no treatment, often associated with other tumors. Because of the high ki67 index, IT-LBP is easily misdiagnosed as T-lymphoblastic lymphoma, causing overtreatment. Understanding the biological behavior, treatment, prognosis and the associated diseases of IT-LBP is important.