The term lymphoma includes a heterogeneous group of malignancies arising from lymphoid tissue, with varied clinical and biological features. It is characterized by the formation of solid tumors in the immune system. Currently, lymphoma becomes a major public health problem in most industrialized countries. Primary lymphoma is referred to those lymphomas which mainly involves the extranodal tissue within the World Health Organization classification of lymphoid neoplasms. Inside them, the Primary Adrenal Lymphoma is extremely rare accounting for less than 1% of all non-Hodgkin's lymphoma cases and 3% of extranodal lymphoma. With this book, we aim to reflect a detailed review of reported medical literature and focusing on the diagnostic aspects of the Primary Adrenal Lymphoma, paying special attention to nuclear medicine and PET/CT imaging.