The usefulness of Fluorine-18 fluorodeoxyglucose PET-CT in detecting extranodal sites in the initial staging of non-Hodgkin and Hodgkin lymphoma (+ Running poster)

Abstract

Hodgkin disease (HD) and non-Hodgkin lymphoma (NHL) represent a spectrum of malignant neoplasms arising from the lymphoid system with an incidence of around 8% of all malignancies. Although they are generally known as tumors of lymph nodes, 25% to 40% of HD/NHL tumors, especially NHL, arise at extranodal sites along the gastrointestinal tract, lung, bone, soft tissues, liver, breast, thyroid, and genitourinary tract. the purpose of this study is to identify the extranodal sites in the initial staging of Hodgkin and non-Hodgkin lymphomas by FDG PET/CT. Seventy-six patients with NHL and 30 patients with HD in period 2017–2020 were retrospectively studied. Patients were selected with the following criteria: have biopsy proven histopathological HD or NHL, and extranodal sites on initial FDG PET/CT. The spleen is considered extranodal region in NHL and nodal organ in HD. Seventy-six patients with NHL (51 males, 25 females), extranodal sites correctly identified by 18F-FDG PET/CT: bone ( n = 33), soft tissues ( n = 24), lung ( n = 22), spleen ( n = 15), stomach ( n = 10), adrenal gland ( n = 8), liver ( n = 8), pleura ( n = 7), peritoneum ( n = 7), pericardium ( n = 5), kidney ( n = 4), mammary gland ( n = 3), thyroid ( n = 3), brain ( n = 2), prostate gland ( n = 2), pancreas ( n = 1), testis ( n = 1). Thirty patients with HD (22 males, 8 females), extranodal sites correctly identified by 18F-FDG PET/CT: Bone ( n = 22), lung ( n = 8), liver ( n = 6), pleura ( n = 2), soft tissues ( n = 1), brain ( n = 1). 18F-FDG PET/CT has become the technique of choice for staging and follow-up in patients with extranodal involvement in HD and in most cases of non-NHL. The potential presence of extranodal involvement should be considered when interpreting FDG PET/CT studies. Awareness of the increasing frequency of the appearance of unusual single extranodal sites of involvement in NHL and HD is important, since their presence may change treatment strategy and overall prognosis.