DISEASE CHARACTERISTICS:

• Malignant solid tumors
• Must have failed conventional treatment or for whom conventional therapy is not available

• Measurable disease by MRI or CT scan

  • Intraocular retinoblastomas may be measured by direct visualization
  • Germ cell tumors may be measured by tumor markers
• No known bone marrow involvement

PATIENT CHARACTERISTICS:

Age:

• Any age

Performance status:

• Lansky 60-100% for patients 16 and under
• Karnofsky 60-100% for patients over 16

Life expectancy:

• At least 8 weeks

Hematopoietic:

• Absolute neutrophil count at least 1,000/mm^3
• Platelet count at least 75,000/mm^3
• If parameters not met, must have adequate stem cell yield

Hepatic:

• Bilirubin no greater than 1.5 times the upper limit of normal (ULN)
• SGOT and SGPT no greater than 2.5 times the ULN (unless liver involvement by tumor)

Renal:

• Creatinine within normal limits OR
• Creatinine clearance at least 70 mL/min

Cardiovascular:

• Fractional shortening greater than 28% on echocardiogram OR
• Ejection fraction at least 55% on RNCA prior to first cycle of thiotepa

Pulmonary:

• DLCO greater than 55% of predicted (only required if there is clinical evidence of pulmonary dysfunction)

Other:

• Not pregnant or nursing
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Prior bone marrow or peripheral blood stem cell rescue allowed

Chemotherapy:

• At least 4 weeks since prior chemotherapy if absolute neutrophil count is less than 1,000/mm^3 or platelet count is less than 75,000/mm^3, and recovered (i.e. adequate stem cells collected to predict hematopoietic recovery)
• No concurrent chemotherapy except for dexamethasone for antiedema effects

Endocrine therapy:

• No concurrent use of corticosteroids used solely as antiemetics

Radiotherapy:

• At least 4 weeks since radiotherapy if absolute neutrophil count is less than 1,000/mm^3 or platelet count is less than 75,000/mm^3, and recovered (i.e. adequate stem cells collected to predict hematopoietic recovery)
• No concurrent radiotherapy

Surgery:

• Not specified