Secondary Lymphoid Tissues ›› Lymph Node ›› Non-neoplastic Lymphadenitis (Non-neoplastic)* Click Here for Full Size › Microscopic Features: Most do not show a completely effaced lymph node (as opposed to neoplastic processes such as lymphomas) The morphology can be variable based on the underlying disease Enlarged reactive secondary follicles are commonly seen Increased number of Immunoblasts are also commonly noted › Normal % blood-PB, marrow-BM, lymphoid tissue-LN: PB: N/A BM: N/A LN: N/A › May Resemble: Follicular Lymphoma Non-neoplastic reactive Lymph node Classical Hodgkin Lymphoma › Differential Diagnoses: Drug-induced Autoimmune-induced Infection Neoplastic (e.g. Follicular lymphoma) Idiopathic (unknown cause) › Classic Immunophenotype: "T"-cells have the "Tiny" CDs: CD2, CD3, CD4, CD5, CD7, CD8 "B"-cells have the "Bigger" CDs: CD19, CD20, CD22 › Misc: Non-neoplastic lymphadenitis can be due to infection, drugs, autoimmune, or ideopathic