However, in most instances, the histological pattern is nonspecific. Fungal and mycobacterial infections cause granulomatous lymphadenitis and some immunological diseases cause non necrotizing granulomatous reaction. Neoplasms Neoplasms are the second common cause for lymphadenopathy. The vast majority of the lymph node neoplasms are malignant. These malignant ones may be primary or metastatic.
Primary neoplasms are malignant proliferations involving lymphoid cells.
These are referred to as malignant lymphomas. Metastatic neoplasms are due to secondary spread to the lymph nodes from an extra nodal site. With many neoplasms, spread is through lymphatics so that regional lymph nodes are the first sites of metastases. Sometimes lymphadenopathy in regional nodes may be the clinical presentation of a malignancy. If malignancy is suspected as a cause of adenopathy, a lymph node biopsy is indicated.