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Despite the utilization of bronchoalveolar lavage (BAL) in children since the early 1970s, several challenges remain once the procedure is complete. These include little documentation on normal controls, the limitations due to the size of the patient, and uniform processes for assessment. It was not until 1995 that a taskforce on pediatric BAL was formed by the European Respiratory Society, and to our knowledge, they remain the only committee evaluating the process [ 1 ]. We examined our procedures and reviewed the literature in an attempt to document the most fruitful practices that would allow improved data comparison and introduce possible investigations.

Morphologically, the distinction between undifferentiated embryonal sarcoma of the liver (UESL) and biliary tract rhabdomyosarcoma (RMS) can be uncertain because of some shared pathologic similarities. Patients with UESL have been consistently but erroneously enrolled in Children's Oncology Group (COG) treatment protocols because UESL was equated with RMS, despite the differing primary treatment modalities of these entities. Review of COG pathology files yielded 20 cases of UESL that were compared to 25 cases of biliary tract RMS. Clinicopathologic features including immunohistochemical staining were examined. In the UESL cases, the male:female ratio was 1:1 and the median age was 10.5 years. Histologically, hyaline globules and diffuse anaplasia were consistently present. The cases of RMS had a male:female ratio of 1.8:1 with a median age of 3.4 years and routinely lacked diffuse anaplasia and hyaline globules. Polyclonal desmin and muscle-specific actin were variably immunoreactive in UESL and RMS; however, myogenin and myogenic regulatory protein D1 (MyoD1) were uniformly negative in UESL and routinely positive in the majority of biliary tract RMS. Myogenin, in particular, was highly significant ( P = 0.0003) in distinguishing RMS from UESL. With a median follow-up of 8 months, 11 of 18 patients with UESL were still alive. The estimated 5-year survival for biliary tract RMS was 66%. Establishing the correct diagnosis of these distinct clinical and pathologic entities is important, as surgery alone may be curative in UESL, whereas initial chemotherapy is often recommended for the treatment of biliary tract RMS.