Tropical splenomegaly syndrome, also known as hyperreactive malarial splenomegaly, occurs due immunological over-stimulation to repeated attacks of malarial infection over a long period of time. Condition is usually seen in malaria-endemic areas like Africa and Indian subcontinent. Tropical Splenomegaly Syndrome is characterized by massive splenomegaly, hepatomegaly, marked elevations in levels of serum IgM and anti-malarial antibodies. The spleen is massively enlarged. It shows dilated sinusoids lined with reticulum cells. There is a marked erythrophagocytosis and lymphocytic infiltration of the pulp. Peripheral smear for malarial parasite is usually negative. Tropical splenomegaly syndrome, also known as hyperreactive malarial splenomegaly, occurs due immunological over-stimulation to repeated attacks of malarial infection over a long period of time. Condition is usually seen in malaria-endemic areas like Africa and Indian subcontinent. Tropical Splenomegaly Syndrome is characterized by massive splenomegaly, hepatomegaly, marked elevations in levels of serum IgM and anti-malarial antibodies. The spleen is massively enlarged. It shows dilated sinusoids lined with reticulum cells. There is a marked erythrophagocytosis and lymphocytic infiltration of the pulp. Peripheral smear for malarial parasite is usually negative. Condition may show features of hypersplenism in severe form like anemia and thrombocytopenia.