Chronic Lymphocytic Leukemia (CLL): This is a common cause of splenomegaly in the elderly, often presenting with gradual onset of symptoms. CLL is a type of cancer that affects the blood and bone marrow, characterized by the production of an excessive number of immature white blood cells.

Liver Cirrhosis: Often leads to portal hypertension, which can cause splenomegaly due to the backflow of blood into the spleen. Elderly patients with a history of alcohol abuse or viral hepatitis are at higher risk.
Myeloproliferative Neoplasms (MPN): Conditions like essential thrombocythemia, polycythemia vera, and primary myelofibrosis can cause splenomegaly. These disorders are characterized by the overproduction of blood cells and can lead to spleen enlargement.
Lymphoma: Both Hodgkin and non-Hodgkin lymphoma can present with splenomegaly. The elderly are at a higher risk for developing lymphoma, making it a significant consideration in this age group.

Splenomegaly due to Infection: Certain infections like endocarditis, tuberculosis, or brucellosis can cause splenomegaly. Although less common, these conditions require prompt diagnosis and treatment to prevent serious complications.
Sarcoidosis: A systemic disease that can affect multiple organs, including the spleen, leading to splenomegaly. It's crucial not to miss this diagnosis due to its potential for significant morbidity if left untreated.
Amyloidosis: A condition characterized by the deposition of abnormal proteins (amyloid) in various tissues, including the spleen, which can lead to splenomegaly. Amyloidosis can be associated with serious complications, making early diagnosis critical.

Gaucher's Disease: A genetic disorder that leads to the accumulation of harmful substances within cells, potentially causing splenomegaly. Although rare, it's essential to consider in patients with unexplained splenomegaly and other systemic symptoms.
Histiocytosis: A group of rare diseases involving abnormal proliferation of histiocytes, which can affect the spleen and cause splenomegaly. These conditions are rare but can be aggressive, necessitating early recognition and treatment.
Splenomegaly due to Parasitic Infections: Certain parasitic infections, such as malaria or kala-azar, can cause splenomegaly. These are rare in many parts of the world but should be considered in patients with a relevant travel history or exposure risk.