Here, Everyone have DD plese put it & I will start .....
.................................................. .......................
DD of huge splenomegally :

2 in blood > Thalasemia - PHTN
2 Infectious diseases > Malaria - Kala azar
2 Tumours > Lymphoma - Leukemia
2 Metabolic & granulomas > Lipid or glycogen storage diseases as (gaucher's disease) - Sarcoidosis