A male patient presented with pain and discomfo in the upper abdominal region. He notices that his abdomen has enlarged than before. He also has significant weight loss. Casoni test is positive in this patient. Diagnosis is:

Echinococcosis (hydatid disease) is caused by the microscopic cestode parasites Echinococcus granulosus and E multilocularis, which form larval cysts in mammalian tissue. Pain or discomfo in the upper abdominal region and weight loss may occur as a result of the cyst enlarging. Casoni's test is used for finding out hydatid disease. It is based on the principle of immediate hypersensitivity. The antigen is used hydatid fluid collected from animal or human cysts. In positive cases a large wheel about 5 cm in diameter, with multiple pseudopodia like projections appear in 25-30 minutes at the test side and fades away in an hour. This is a sensitive test but not a specific test. Ref: Medical Parasitology By Bhatia, 2002, Page 221.