Osteosarcoma Arising in Noonan Syndrome/RASopathy Complex: First Case Report

Area of Science:

• Genetics and developmental biology
• Oncology
• Rare diseases

Background:

• Noonan syndrome (NS) is a RASopathy characterized by genetic heterogeneity, with PTPN11 mutations in ~50% of cases.
• NS is associated with various malignancies, but osteosarcoma has not been previously reported.
• Polyostotic fibrous dysplasia (FD) is a rare bone disorder affecting multiple bones.

Purpose of the Study:

• To report the first case of osteosarcoma in a patient with Noonan syndrome.
• To highlight the potential association between NS, fibrous dysplasia, and osteosarcoma development.

Main Methods:

• Case report of a male patient with Noonan syndrome.
• Detailed clinical history and diagnostic findings.
• Review of literature for similar cases.

Main Results:

• The patient presented with osteosarcoma of the mandible.
• The osteosarcoma developed in the context of long-standing polyostotic fibrous dysplasia of craniofacial bones.
• This represents the first reported instance of osteosarcoma in a Noonan syndrome patient.

Conclusions:

• This case expands the known spectrum of malignancies associated with Noonan syndrome.
• The co-occurrence of NS, FD, and osteosarcoma warrants further investigation into potential underlying mechanisms.
• Clinicians should consider osteosarcoma in the differential diagnosis for patients with NS and craniofacial abnormalities.