Light- and Electron- microscopic and Immunohistochemical Studies of Human Rhabdomyosarcomas. Comparisons Among Primary Tumors, Heterotransplants in Nude Mice, and Cultured Cells from 13 Patients

Eighteen human rhabdomyosarcomas (RMS) were transplanted into the sub-cutaneous space on the back of nude mice. Thirteen of the tumors gave rise to transplantable tumors that were further examined morphologically and immuno-histochemically. The morphology of the transplanted tumors was similar to that of the primary tumors. Immunohistochemically, five primary tumors and six transplanted tumors were reacted with both desmin and myoglobin. However, in eleven cases cultured cells derived from the transplanted tumors, which showed elongated to strap-spindle-shaped cytoplasm resembling myotubules, reacted more intensely with both myoglobin and desmin. On ultrastructural examination, six primary tumors and seven transplanted tumors were found to have myofilaments or Z-bands. However, cultured cells showed myofilaments or Z-bands in their cytoplasm in all cases examined. We concluded that, on xeno-grafting, the histologic characteristics of the primary tumor are essentially con-served, and that tumor cells under culture conditions undergo an increased differentiation of skeletal muscle. These human RMS strains in nude mice and in cell lines will provide an excellent model system for investigating the biology of RMS and for further study of the molecular events underlying the genesis of this tumor

Focal fractionated radiotherapy for intramedullary spinal arteriovenous malformations: 10-year experience.

Object. Radiosurgical treatment of spinal arteriovenous malformations (AVMs) is becoming a practical therapeutic option as methodology improves, but no comparative study has yet been published on focal fractionated radiotherapy. The authors report their experience with conventional and hypofractionated radiotherapy for spinal AVM. Methods. Candidates for this study were patients who experienced symptoms due to an intramedullary AVM but were ineligible for embolization or surgery. Of 21 patients with spinal AVMs, 10 cases in a 10-year period met this criterion. Angiography and contrast-enhanced computerized tomography scanning were used for treatment planning in all cases. Fractionated radiotherapy was performed using a linear accelerator, extracranial immobilization system, and frequent orthogonal linacographic verification. The starting radiation dose was 32 Gy in two, 36 Gy in three, and 40 Gy in two patients, in a regimen involving 1.8 to 2–Gy daily fractions; this was recently changed to a hypofractionation schedule of 30 Gy (in eight sessions) in one and 20 Gy (in four sessions) in two patients. Results. The follow-up period ranged from 26 to 124 months (median of 49 months). There were no hemorrhages nor any adverse reactions attributable to irradiation. Of the seven patients who consented to undergo follow-up angiography, the nidus size decreased in five, but complete obliteration did not occur in any patient. Conclusions. Because no patient experienced adverse effects, the maximum tolerable radiation dose for the spinal cord associated with an AVM could not be identified, although it presumably is higher than those administered. The lack of rebleeding in patients in whom complete angiographic occlusion was absent suggests that the natural history of spinal AVMs may be less aggressive than previously reported

Impact of carbon ion radiotherapy for primary spinal sarcoma.

BACKGROUND: Spinal sarcomas have been one of the most challenging diseases for orthopedic surgeons. The objective of this study was to retrospectively analyze carbon ion radiotherapy (CIRT) treatment results for spinal sarcoma.\nMETHODS: Forty-seven patients with 48 medically unresectable spinal sarcomas, excluding sacral tumors, received treatment with CIRT between 1996 and 2011. All patients were enrolled in phase 1/2 and phase 2 clinical trials of CIRT for bone and soft tissue sarcoma. The applied dose ranged from 52.8 gray equivalents (GyE) to 70.4 GyE (median, 64.0 GyE) in 16 fixed fractions over 4 weeks.\nRESULTS: The median patient age was 54 years, and the cohort included 24 men and 23 women. Thirty-five patients were without prior treatment, and 12 patients had locally recurrent tumors after previous resection. The median follow-up was 25 months, and the median survival was 44 months (range, 5.2-148 months). The 5-year local control, overall survival, and progression free rates were 79%, 52%, and 48%, respectively. None of the 15 patients who had tumors measuring <100 cm(3) had a local recurrence. No fatal toxicities occurred during follow-up. One patient each had a grade 3 late skin reaction and a grade 4 late skin reaction. Vertebral body compression was observed in 7 patients. One patient had a grade 3 late spinal cord reaction. Twenty-two of the surviving 28 patients who had primary tumors remained ambulatory without supportive devices.\nCONCLUSIONS: CIRT appears to be both effective and safe for the treatment of patients with unresectable spinal sarcoma. Cancer 2013;119:3496-3503.. &copy; 2013 American Cancer Society