Fine-needle aspiration cytology of pleuropulmonary blastoma: a case report with unusual features.

Pleuropulmonary blastoma (PPB) is a rare and aggressive intrathoracic neoplasm of childhood, typically presenting as a pulmonary and/or pleural-based mass with cystic, solid, or combined features. Histologically, the tumor is well characterized with a mixture of primitive mesenchymal and variably differentiated sarcomatous components, and the cytologic features described in the three previous reports are also compatible to the histologic ones. Now, we present another case of PPB showing unusual features. A 3-yr-old boy presented with a pleural- or chest wall-based tumor. The fine-needle aspiration cytologic smears were highly cellular with poorly differentiated cells showing variable size and shape rather than those of typical blastemal cells. The histologic findings were also distinctive, exhibiting diffuse sheets of poorly differentiated cells without typical blastemal cell component. Diagnosis was confirmed by the support of immunohistochemical and ultrastructural features. The patient underwent a typical aggressive clinical course to death within 8 mo after diagnosis.