Extensive Extranodal Involvement in a case of Non-Hodgkin's Lymphoma with sparing of lymph nodes and lymphatic organs

Non-Hodgkin lymphoma (NHL) is a group of malignant lymphoproliferative disorders arising predominantly in the lymph nodes with various clinical and histological characteristics. At least 25% of NHL originates from tissues other than lymph nodes and sometimes even from sites that do not contain lymphoid tissue. These are referred to as primary extranodal lymphomas (pENLs). pENL is a universal diagnostic challenge to the clinicians and pathologists due to their varied clinical presentations, morphological mimicry, and molecular alterations. The GIT is the most common site of pENL followed by nasopharynx/oropharynx, testis, uterus/ovary, thyroid, and central nervous system. Long bones (tibia), maxillary sinus, skin, and paraspinal soft tissues are the other rare anatomic sites of pENL. We reported a case of a 60-year-old female presented with pain and mass in the pelvis region. 18F-Fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) and fused PET/CT was done, which revealed extensive extranodal involvement of the lung, bilateral kidneys, uterus, ovaries, bones, and muscles with no involvement of lymph nodes or lymphomatous organs. Extensive extranodal involvement with sparing of lymphomatous organ has not been reported earlier.