Extranodal involvement in lymphoma – A Pictorial Essay and Retrospective Analysis of 281 PET/CT studies

OBJECTIVE(S): The aim of this study is to evaluate the role of PET-CT in identification of different patterns of extranodal involvement in Hodgkin’s disease (HD) and Non-Hodgkin’s Lymphoma (NHL) and to enlist the common sites of extranodal involvement in each histological type and compare our results with the existing literature. METHODS: In this retrospective study of 281 cases of lymphomas of various histologies, we illustrate the spectrum of PET/CT features of extranodal lymphoma (ENL) of commonly involved organs and compare our result with the literature. RESULT: Extranodal appearance in lymphoma is strikingly varied. Diffuse large B cell lymphoma (DLBCL) is the commonest histological subtype and gastrointestinal tract is the commonest anatomical subsite in NHL. Skeletal system is the commonest site for involvement in HD. CONCLUSION: A broad spectrum of extranodal organs is involved in various subtype of lymphoma which can be depicted in PET-CT in the most appropriate manner. Familiarity with the pattern of involvement is essential for comprehensive management.