Pulmonary involvement by Echinococcus alveolaris.

Twenty cases of pulmonary involvement by E. alveolaris were analyzed and classified into one of two radiological types-Type l: multiple, small, ill-defined, irregular lesions that are peripherally located and develop slowly; and Type II: variable changes of the right lung base. Type 1 has a hematogenous metastatic origin, while Type II is caused by hepatic processes penetrating the hemidiaphragm. Differential diagnosis, which includes neoplasms and infections, specifically E. cysticus, is difficult. Diagnosis appears to be possible only when based on a combination of Type 1 changes, laboratory findings, and geographic occurrence.