[44] Clinicopathologic Analysis of Adult Alveolar and Embryonal Rhabdomyosarcoma: A Study of 62 Cases

AT Deyrup, K Thway, C Fisher, W-L Wang, AJ Lazar, RL Jones, M Tighiouart, SW Weiss. Emory University, Atlanta; Royal Marsden, London, United Kingdom; MD Anderson, Houston

Background: Embryonal (ERMS) and alveolar (ARMS) rhabdomyosarcoma are rare in adults and are not well characterized in this patient population: we report 62 cases of ERMS and ARMS arising in patients 40 years and older.
Design: Sixty-two patients who were 40 years or older with RMS were identified from surgical pathology and consultation files, excluding pleomorphic RMS. Clinicopathologic information included tumor site, patient age, detailed treatment information and translocational analysis.
Results: Sixty-two adult patients (age 40-82 yrs; mean 56 yrs; 35M:27F) with RMS from 1 to 40 cm (mean 10.2 cm) were identified. Tumors arose in the head/neck (n=19), thorax (n=15), extremities (n=13), abdomen/ pelvis(n=9) and genitourinary system (n=6) and were classified as Intergroup RMS Pretreatment staging system 1(10), 2(3), 3(26) and 4(19). Microscopically, 29 cases were classified as ERMS and 14 as ARMS. Mitotic activity ranged from 0-126 mit/10 hpf (mean 34); 37 cases showed at least focal necrosis. By immunohistochemistry, 47/47 tumors expressed desmin, 41/41 expressed myogenin and 18/18 expressed MyoD1. 26 cases were translocation-negative; 4 cases had t(2;13) and 1 had t(1;13). 4 cases with alveolar histology were translocation-negative. No ERMS was translocation-positive. Follow-up information was available in all cases: 40 patients died of disease (0-78 mos, mean 18.2 mos). 5-year disease-specific survival was 24.4%; of the 22 patients who did not die of disease, survival ranged from 0 to 168 mos (mean 55 mos). 34 patients had metastatic disease (lung, 18; lymph node, 17; soft tissue, 10; bone, 8; liver 4; other, 9). 40 patients were treated with chemotherapy and 30 patients received radiation. By univariate analysis, IRS stage (P=0.001), size (P=0.007), metastasis(P=0.02) and location in abdomen/pelvis or thorax compared to extremity (P=0.03) were significant indicators of death from disease. Patient age (P=0.88), sex (P=0.13), alveolar histology (P=0.77) and treatment with chemotherapy (P=0.15) did not affect disease-specific survival.
Conclusions: ARMS and ERMS arising in adults differ from those in children: 1) alveolar histology is not associated with an increased risk of death; 2) chemotherapy does not significantly affect disease-specific survival; and 3) adults present with advanced stage disease and have a worse prognosis.
Category: Bone & Soft Tissue

Monday, March 9, 2009 1:00 PM

Poster Session II # 18, Monday Afternoon