Lymphadenopathy is a common clinical finding, affecting patients of all ages. The majority of lymphadenopathies are reactive processes of lymph nodes in response to a variety of exogenous and endogenous stimulants. They are non-neoplastic conditions that can mimic lymphoma and other malignant tumors. Therefore their recognition and differential diagnosis is of great importance in order to rule-out the neoplastic disease. Signs of malignant etiology include lymph nodes >1,5cm in diameter, supraclavicular localization and generalized lymphadenopathy. A metastatic carcinoma is always in the differential diagnosis of localized lympadenophaty in older individuals. In case of generalized lymphadenopathy lymphomas, metastatic solid tumors and various benign etiologies need to be considered. The reactive lymphadenopathies are grouped into four major categories according to their predominant architectural histologic pattern: follicular-nodular, sinus, interfollicular or mixed, and diffuse. As reactive conditions of the lymph nodes are dynamic processes the predominant pattern may differ depending on when during the course of the disease the biopsy is performed. The most common reactive lymphadenopaties are follicular hyperplasia and toxoplasmic lymphadenitis. Nowdays some lymphadenopathies with foreign-body reaction are side effects of silicone prostheses (silicone lymphadenopathy) and various contrast media (lipid lymphadenopathy). A specific diagnosis and differentiation from neoplastic disease often requires correlation among the morphologic features, the clinical history, serologic studies, immunohistochemistry and molecular genetic analysis.