[733] Rhabdomyomatous Tumors (RT) after Chemotherapy for Metastatic Testicular Germ Cell Tumors: A Study of 7 Cases
JA Clevenger, RS Foster, TM Ulbright. Indiana University School of Medicine, Indianapolis, IN
Background: In advanced testicular germ cell tumors (TGCT), retroperitoneal lymph node dissection (RPLND) is often performed for the resection of residual post-chemotherapy masses. Teratoma is a good prognostic finding but sarcoma, including rhabdomyosarcoma, carries a poor prognosis. Rarely, sizable nodules of differentiated skeletal muscle are found, and it is unclear if these should be considered as teratoma or sarcoma.
Design: A computer search for RPLND specimens having substantial foci of pure rhabdomyomatous elements and lacking non-teratomatous GCT elements identified 4 cases that were confirmed on retrospective slide review. Cases of rhabdomyosarcoma, based on mitotic activity and a primitive cell component, were excluded. In addition, 3 cases that were previously reviewed by the senior author were included, although the slides were unavailable for review.
Results: Clinical and pathological features are summarized in the Table.
Clinical & Pathologic Features| Age at RPLND | TGCT | Interval to RT | Size of RT | Rx after RPLND | F/U after RPLND | | 27 yrs | T, YST | 4.7 yrs | 5 cm | ChemoRx | Mediastinal T, 1.7 yrs | | 28 yrs | S, T | 0.3 yrs | 2 cm | None | NED, 2.6 yrs | | 23 yrs | YST, CC, EC | 0.2 yrs | 1.5 cm | None | NED, 3.4 yrs | | 19 yrs | T, scar | 0.5 yrs | 2-3 cm | None | NED, 2.2 yrs | | 18 yrs | YST, T, EC, CC | 0.7 yrs | ? | None | RP T, 1.3 yrs; lung nodules*, 3.7 yrs | | 18 yrs | T, PNET, RMS, YST | 0.3 yrs | ? | ? | Lost | | ? | ? | ? | ? | ? | Lost | CC - choriocarcinoma; EC - embryonal carcinoma; F/U - follow-up; NED - no evidence of disease; PNET - primitive neuroectodermal tumor; RMS - rhabdomyosarcoma; RT - rhabdomyomatous tumor; RP - retroperitoneal; S - seminoma; T - teratoma; * clinically teratoma but not confirmed
The RTs consisted of nodular to diffuse aggregates of fetal-type rhabdomyocytes with central to peripheral nuclei and abundant, eosinophilic, fibrillar cytoplasm with occasional cross striations. Elongated myotubes with multiple nuclei in a common sarcoplasm occurred at least focally in all cases. Mild to moderate nuclear atypia, including nuclear enlargement and nucleolar prominence, was present, but mitotic activity, necrosis and a primitive cellular component were absent. All but one case were associated with other teratomatous elements.
Conclusions: RTs in RPLND specimens after chemotherapy for metastatic TGCTs exhibit clinical behavior similar to teratoma rather than rhabdomyosarcoma.
Category: Genitourinary (including renal tumors)
Monday, March 9, 2009 1:00 PM
Poster Session II # 102, Monday Afternoon
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