Cytopathology: LC06-1 HODGKIN LYMPHOMA: DIAGNOSTIC CRITERIA AND PITFALLS.
[hodgkin lymphoma, classical]
The histopathological and fine-needle aspiration (FNA) cytologic diagnosis of Hodgkin lymphoma (HL) is based on demonstration of pathognomonic mononucleated Hodgkin and bi- to multinucleated Reed-Sternberg (HRS) cells among reactive cellular components composed of lymphocytes, benign histiocytes, neutrophils and eosinophils. In the WHO classification, Hodgkins lymphoma is classified as nodular lymphocytic predominant HL (NLPHL) and classical HL which is in turn sub-classified into lymphocyte-rich (LR), mixed cellular (MC), lymphocytic depleted (MC) and nodular sclerosis (NS) types. The sub-classification of classical HL into LR, MC, and LD depends on relative proportions of neoplastic HRS cells and reactive cellular components. Whereas in HL-NS shows a special type of R-S cells called lacunar cells, NLPHL is characterized by popcorn cells. CHL-MC to some extent and other HL subtypes to a large extent may pose diagnostic challenges in the cytologic material. Reed-Sternberg-like cells have been reported in benign lympho-proliferative conditions like reactive hyperplasia and infectious mononucleosis, and certain of non-Hodgkin lymphoma subtypes as well as non-lymphoid malignancies like metastatic carcinoma, melanoma, sarcomas and germ cell tumors. Non-Hodgkin lymphoma subtypes, e.g., anaplastic large cell lymphoma, T-cell-histiocytic-rich B-cell lymphoma, and pleomorphic peripheral T-cell lymphoma, which can be misdiagnosed as Hodgkin lymphoma, need immunohistochemical studies to be differentiated.
