Inclusion Criteria:

• Patients with histologically confirmed diagnosis of extra-abdominal aggressive fibromatosis (desmoid tumor).
• At least one of the following:
  • Desmoid tumor that has shown stability in size over consecutive axial imaging (CT or MRI) at least 3 months apart; AND
  • Presence of any tumor-related symptoms; OR
  • An increase in size based on consecutive axial imaging (CT or MRI). Additionally, for patients with a desmoid tumor which has been irradiated, at least a 10% increase in size by volume since receiving radiotherapy is required.
• ECOG Performance status of ≤ 1.
• Able to participate in three guided injection procedures.
• Able to undergo a MRI with and without contrast of the tumor site.
• Age ≥ 18 years and ≤ 89 years old.
• Willing to sign an informed consent form.
• Willing to comply with protocol procedures including required 21 month follow up after last injection.

Exclusion Criteria:

• Allergy to the test drug or a component of its formulation.
• Patients with a desmoid tumor which has been stable in size and without symptoms or decreased in size over the prior three months utilizing axial imaging according to the following criteria:
  • 10% when comparing a prior CT scan to a current MRI; or
  • more than 5% when comparing a prior MRI to a current MRI.
• The patient must not be on anticoagulation (aspirin okay).
• The patient should not be pregnant or trying to become pregnant, and willing to use adequate contraception during study participation to avoid pregnancy.
• The patient should not be breastfeeding.
• Active infection that in the opinion of the investigator compromises the patient’s participation (i.e., a UTI is ok).
• A diagnosis of idiopathic thrombocytopenia purpura.
• Undergoing concomitant treatment (including radiation, systemic treatment, surgery, or other tumor directed therapy). The patient must be off of the systemic therapy for a period of at least 5 drug half-lives prior to enrolling in the study.
• Uncontrolled or poorly controlled diabetes mellitus.
• Has an uncontrolled  illness including, but not limited to, uncontrolled infection, or psychiatric illness/social situations that, in the opinion of the investigator, would limit compliance with study requirements.