Pleuropulmonary blastoma in an adult: an initial case report.

Pleuropulmonary blastoma (PPB) is a unique dysontogenetic neoplasm of childhood. Its primitive, sarcomatous features are analogous to those of other dysembryonic or dysontogenetic tumors, such as Wilms tumor, hepatoblastoma, neuroblastoma, and embryonal rhabdomyosarcoma. PPB typically presents in young children, most younger than 5 years, as a pulmonary and/or pleural-based tumor with cystic, solid, or combined cystic and solid features. These neoplasms are characterized histologically by primitive mesenchymal or a mixture of primitive and sarcomatous components and generally have an unfavorable clinical outcome: death occurs within 1-2 years after diagnosis.Clinicopathologic and radiographic findings of a man age 36 years with a cystic and solid mass in the left hemithorax were reviewed and compared with previously studied cases of PPB.Pathologic examination of the mass revealed a cystic and solid neoplasm composed of malignant mesenchymal cells that were immunoreactive for vimentin and muscle specific actin and focally for desmin. The architectural and cytologic appearances as well as the immunohistochemical profile were those of type II PPB.To the authors' knowledge, all previously reported cases of PPB occurred in children age 12 years or younger. They believe that this case represents the first occurrence of PPB in an adult and documents the finding that, although it is uncommon, adults can develop primitive neoplasms that are usually associated with the pediatric population. In addition, the clinicopathologic features observed in the authors' adult patient were consistent with their experience with this tumor type in children. The patient died less than 1 year after diagnosis.