Cutaneous and subcutaneous Ewing's sarcoma: an indolent disease.

PURPOSE: The occurrence of extraosseous Ewing's sarcoma (ES) in deep soft tissues has been well described, but cases in which this tumor occurs in a primary cutaneous or subcutaneous site have rarely been reported. The superficial variant may be less aggressive than are the more common bony and deep soft tissue counterparts with an apparently favorable outcome. A retrospective review of patients with cutaneous or subcutaneous ES was conducted to analyze outcome and patterns of failure. METHODS AND MATERIALS: Between July 1985 and March 1997, 14 patients with cutaneous or subcutaneous ES were treated at St. Jude Children's Research Hospital. The median age at presentation was 16 years (range 7-21 years). Anatomic locations included trunk and pelvis (7), upper or lower extremity (4), and head and neck (3). The median size of the lesion was 3 cm (range, 1-12 cm). Thirteen had definitive surgical resections, and one had biopsy of the mass at the time of referral. They were enrolled on institutional (12) or cooperative group (2) protocols. All patients received chemotherapy, composed of vincristine, doxorubicin, cyclophosphamide, ifosfamide, etoposide, and dactinomycin. Patients on institutional protocols received radiation (36 Gy) to the operative bed (150-180 cGy/fraction/day). Postoperative radiotherapy was omitted for 2 patients who had complete resection on the cooperative group study.
RESULTS: No patients had metastatic disease at presentation. Thirteen patients had wide local excision of the primary tumors prior to enrollment on chemotherapy; surgical margins were negative (10), microscopically positive (2), and indeterminate (1). Eleven patients received radiotherapy to the tumor bed; 2 with clear surgical margins were treated without irradiation. The patient who had biopsy only received induction chemotherapy followed by definitive surgical resection and postoperative radiotherapy. The median follow-up was 77 months (range 17-111 months). None of the patients has developed local recurrence or distant metastasis. Several of the patients developed treatment-related sequelae, including veno-occlusive disease of the lung and hemorrhagic cystitis (1), myelodysplastic syndrome (1), chemotherapy-induced ovarian failure (1), moist desquamation (1), and dermatofibroma within the radiotherapy volumes (1).
CONCLUSIONS: Cutaneous and subcutaneous ES are associated with an indolent course and a favorable prognosis when treated with combined modality therapy. Elimination of radiation therapy following complete resection has been tested in the POG 9354 trial. The high rate of local control, low rate of metastatic disease, and excellent overall outcome may suggest a role for less intensive chemotherapy, as well as tailoring to diminish or avoid radiation therapy in completely resected cases, with a goal to minimize toxicity while maintaining a high cure rate.