Cytopathologic Diagnosis of Hodgkin Lymphoma: Realities Outlined.

[BACKGROUND] The historical journey of Hodgkin lymphoma (HL) has undergone a unique path since its inauguration as a malignant entity. Then it was further classified into classical HL (cHL) and nodular lymphocyte-predominant HL (NLPHL). Since then, the diagnosis was traditionally made on histological examination of tissue sections. The procurement of core, open, or excisional tissue biopsy used to be the backbone prerequisite to make the diagnosis. This dependence of diagnosis on histological sections has recently been challenged.

[SUMMARY] In this review, making the diagnosis of HL by aspiration cytology is offered. Emerging evidence supports that in specialized centers with appropriate tools (specifically immunophenotyping by immunohistochemical stains) the diagnosis of cHL can be made confidently on cytological specimens with high levels of accuracy. The recent improvements in flow cytometric technology further assists in supporting the diagnosis of cHL on cytology. New parameters are now being reported as flow cytometric features of cHL, potentially distinguishing it from close mimickers.

[KEY MESSAGES] The diagnosis of cHL can be achieved utilizing cytomorphology in combination with appropriate necessary ancillary studies. On the other hand, NLPHL still lags behind in these newer discoveries and its final diagnosis should still be made on histological tissue sections.