Management of Abdominal Tumors in Neurofibromatosis

Diagnostic Approach

The American College of Medical Genetics and Genomics recommends annual general medical evaluation for patients with NF1, including assessment for signs/symptoms of MPNST 2
Key warning signs for MPNST include progressive, persistent pain, rapid growth of existing lesions, neurologic symptoms, and deep, truncal location of plexiform neurofibromas 1
MRI is the mainstay of imaging for diagnosis, local staging, and follow-up of abdominal tumors in NF1 3
18F-FDG PET/CT is highly valuable for detecting malignant transformation with a sensitivity of 0.89 and specificity of 0.95 1

Surgery is the primary treatment for high-grade MPNST with the aim of achieving clear margins, and has demonstrated benefit even for large, abdominal MPNSTs 1
Adjuvant therapy may have a potential role in some non-metastatic MPNST patients, with response rates to doxorubicin plus ifosfamide approximately 21% 1
Complete surgical resection is recommended for atypical neurofibromatous neoplasms (ANNUBP) when feasible, with close surveillance due to uncertain biologic potential 2

MRI surveillance is recommended to assess response to treatment, with serial imaging with CT or MRI every 6-12 months depending on growth rate 5
Close follow-up is essential for patients with MPNSTs due to high risk of recurrence 1

The National Neurofibromatosis Foundation notes that risk of NF1-associated MPNST increases with age: 8.5% by age 30, 12.3% by age 50, and 15.8% by age 85 2
Life expectancy in NF1 is reduced by 8-15 years compared to the general population, primarily due to malignant neoplasms 2
The American Cancer Society recommends that women with NF1 undergo annual mammogram starting at age 30 and consideration of breast MRI with contrast between ages 30-50 2