Inclusion Criteria

DISEASE CHARACTERISTICS:

- Diagnosis of plexiform neurofibroma which is progressive, symptomatic, or life
threatening and for which there is no other standard medical management or surgical
option

- Histologic confirmation of tumor is not required in the presence of consistent
clinical and radiographic findings provided the following are true:

- No clinical observation or scan suggestive of malignant transformation

- Meets ≥ 1 of the following diagnostic criteria for neurofibroma type 1 (NF1):

- Six or more cafe-au-lait spots (> 0.5 cm in prepubertal patients or > 1.5
cm in post pubertal patients)

- Freckling in axilla or groin

- Optic glioma

- Two or more Lisch nodules

- A distinctive bony lesion (e.g., dysplasia of the sphenoid bone, dysplasia,
or thinning of long bone cortex)

- A first degree relative with NF1

- No history of malignant peripheral nerve sheath tumor

- No active visual pathway glioma

- No active brain tumor or brain metastases

PATIENT CHARACTERISTICS:

Performance status

- ECOG 0-2

Life expectancy

- At least 12 months

Hematopoietic

- Absolute neutrophil count > 1,500/mm^3

- Hemoglobin > 10 g/dL

- Platelet count > 100,000/mm^3

Hepatic

- Bilirubin < 1.5 mg/dL

- SGPT ≤ 2 times upper limit of normal

- No significant hepatic dysfunction

Renal

- Creatinine based on age as follows:

- ≤ 0.8 mg/dL (for patients age 5 years and under)

- ≤ 1.0 mg/dL (for patients age 6 to 10 years)

- ≤ 1.2 mg/dL (for patients age 11 to 15 years)

- ≤ 1.5 mg/dL (for patients age 16 to 21 years) OR

- Creatinine clearance ≥ 70 mL/min

Cardiovascular

- No significant cardiac dysfunction

- No severe cardiovascular disease

- No cardiac arrhythmia requiring chronic treatment

- No congestive heart failure

- No symptomatic ischemic heart disease

Pulmonary

- No significant pulmonary dysfunction

Other

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

- No serious infection

- No other significant unrelated systemic illness

- No significant organ dysfunction

- No other malignancy except surgically cured nonmelanoma skin cancer or carcinoma in
situ of the cervix

- No history of severe psychiatric condition or psychiatric disorder requiring
hospitalization

- No history of suicidal ideation or attempt

- No thyroid dysfunction unresponsive to therapy

- No uncontrolled diabetes mellitus

- No history of HIV positivity

- No alcohol or drug abuse

PRIOR CONCURRENT THERAPY:

Biologic therapy

- No concurrent immunotherapy

- No concurrent colony-stimulating factors (e.g., erythropoietin or filgrastim [G-CSF])

Chemotherapy

- No concurrent chemotherapy for this disease

Endocrine therapy

- No concurrent chronic systemic corticosteroids

- No concurrent hormonal therapy for this disease

Radiotherapy

- No concurrent radiotherapy for this disease

Surgery

- Prior surgery allowed provided it has been at least 21 days since surgery and there
is presence of residual tumor

Other

- Recovered from prior therapy

- More than 30 days since prior investigational agents