Mixed embryonal/alveolar rhabdomyosarcoma of the prostate: report of a case with molecular genetic studies and literature review.
ABSTRACT Alveolar rhabdomyosarcoma (RMS) is 1 of 2 main subtypes of RMS in the pediatric age group and tends to occur in the extremities. The urogenital tract is another common site for RMS, but this typically involves the embryonal subtype including sarcoma botryoides. We report a 28-year-old male with a prostatic tumor that was excised en bloc and showed a RMS with separate areas of embryonal and solid alveolar morphologies at the light microscopic level. Both areas showed diffuse nuclear expression for myogenin, and both areas expressed the PAX3-FKHR fusion gene, a genetic change associated with alveolar but not embryonal RMS. A review of the literature documented only 5 cases of RMS primary to the prostate showing alveolar or mixed histology. Ours is the 6th case and the 1st with molecular findings. Although the diagnostic category of mixed embryonal/alveolar RMS remains in use, the nature of this type of RMS is incompletely understood. In our case, although the morphology was mixed embryonal/alveolar, at the genetic level this tumor was alveolar in nature.
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ABSTRACT: Clinical and histopathologic features are often inadequate for accurate prediction of relapse or survival of individual patients with rhabdomyosarcoma (RMS). We therefore studied the cellular DNA content (ploidy) of RMS cells in relation to histology and response to therapy in 37 patients with unresectable tumors. Using flow cytometric techniques, we found that about one third of patients had diploid tumor stem lines, regardless of the histologic subtype. In the group with abnormal ploidy, a hyperdiploid classification (1.10 to 1.80 times the DNA content of normal diploid cells) was exclusively associated with embryonal histology (P = .001). By contrast, near-tetraploidy (1.80 to 2.60 times the DNA content of normal cells) was strongly associated with alveolar histology (P = .001). Thus, in these histologic subtypes of RMS, abnormal ploidy appears to arise through different mechanisms. Tumor-cell ploidy had a significant impact on survival that was especially apparent in patients with unresectable, nonmetastatic (group III) tumors. In this subgroup, hyperdiploidy conferred the best prognosis and diploidy the worst (P less than .0001). None of the eight patients with diploid tumors survived for more than 18 months. Tumor-cell ploidy was the best predictor of treatment outcome for patients with either embryonal (P less than .001; relative risk, 25.5) or alveolar (P = .073; relative risk 7.1) RMS and contributed significantly after adjustment for disease stage and anatomic site. Patients with unresectable diploid RMS have an unacceptably high risk of treatment failure, justifying new therapeutic approaches for this distinct subgroup.Journal of Clinical Oncology 02/1991; 9(1):159-66. · 18.04 Impact Factor
- Pathologica 01/1983; 75(1040):797-801.
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ABSTRACT: Cytogenetic studies of a rhabdomyosarcoma of mixed embryonal and alveolar histology in an 11-month-old male revealed a single structural abnormality, t(1;13)(p36;q14). This abnormality may define a subset of patients with a variant of the t(2;13)(q35;q14) translocation frequently seen in alveolar rhabdomyosarcoma.Genes Chromosomes and Cancer 12/1991; 3(6):483-4. · 3.55 Impact Factor