DISEASE CHARACTERISTICS:

Histologically proven primary CNS malignancy, neuroblastoma or sarcoma that is refractory to standard therapy or for which no standard therapy exists and disease can not be cured by surgery.

PRIOR/CONCURRENT THERAPY:

Recovered from toxic affects of all prior therapy.

No investigational agent within past 2 weeks.

BIOLOGY THERAPY: Not specified.

CHEMOTHERAPY:

No myelosuppressive therapy within past 3 weeks.

No nitrosourea within past 6 weeks.

ENDOCRINE THERAPY: If receiving dexamethasone dose must be stable for at least 2 weeks.

RADIOTHERAPY: Not specified.

SURGERY: Not specified.

PATIENT CHARACTERISTICS:

Age: 3 to 21.

Performance status: ECOG 0-2.

Life expectancy: At least 8 weeks.

HEMATOPOIETIC:

AGC greater than 1500/mm(3).

Hemoglobin greater than or equal to 8.0 g/dL percent.

Platelet count greater than 100,000/mm(3).

For patients with bone marrow involvement or history of bone marrow transplantation or craniospinal radiotherapy: AGC greater than 750/mm(3), Hemoglobin greater than 6.0 g/dL, Platelet count greater than 50,000/mm(3).

HEPATIC:

SGOT, SGPT or alkaline phosphatase less than 3 times upper limit of normal.

Bilirubin no less than or equal to 1.5 times upper limit of normal.

RENAL:

Ages 3-5 Creatinine no greater than 0.8 mg/dL.

Ages 5-10 Creatinine no greater than 1.0 mg/dL.

Ages 10-15 Creatinine no greater than 1.2 mg/dL.

Ages 16-21 Creatinine no greater than 1.5 mg/dL.

OTHER:

All patients or their legal guardians (if the patient is under 18 years old) must sign a document of informed consent indicating their understanding of the investigational nature and the risks of this study.

For patients with brain tumors who are over 18 years of age, a DPA should be signed.

Not pregnant or nursing.

Not allergic to etoposide.

No acute or chronic medical or psychiatric condition or laboratory abnormality that may increase the risks associated with study participation/study drug administration or may interfere with the interpretation of study results.