Lymphoma: Lymphoma, particularly non-Hodgkin lymphoma, is known to present with systemic symptoms including fever, night sweats, and weight loss. The fever can be due to the tumor itself or secondary infections.

Leukemia: Various forms of leukemia, such as acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL), can present with fever, either due to the disease process itself or due to infections resulting from immunosuppression.
Solid Tumors with Metastasis: Certain solid tumors like lung, breast, or renal cell carcinoma, especially when metastasized, can cause fever. This may be due to tumor necrosis, infection, or paraneoplastic syndromes.

Tumor Lysis Syndrome: Although not a malignancy itself, tumor lysis syndrome is a life-threatening complication that can occur after treatment of certain cancers, particularly those with high cell turnover rates like lymphomas and leukemias. It presents with fever, among other symptoms, and requires immediate attention.
Neutropenic Fever: This condition occurs in patients with significantly low neutrophil counts, often due to chemotherapy. It's crucial to identify and treat promptly as it can rapidly progress to sepsis.

Castleman Disease: A rare disorder that involves an overgrowth of cells in the body's lymph nodes. It can present with fever, along with other systemic symptoms.
Histiocytosis: A group of rare diseases involving abnormal proliferation of histiocytes, which can present with fever among other systemic symptoms.
Paraneoplastic Syndromes: Certain malignancies can induce paraneoplastic syndromes, which are rare disorders that are triggered by an abnormal immune system response to a cancer, and can present with fever.