Case report: Tenosynovial giant cell tumor

Area of Science:

• Oncology
• Genetics
• Pathology

Background:

• Tenosynovial giant cell tumor (TGCT) is a rare neoplastic proliferation originating in the synovium of joints and tendon sheaths.
• Diagnosis often relies on imaging and biopsy due to non-specific symptoms like pain and swelling.
• Recurring genetic abnormalities, particularly involving the CSF1 gene, are characteristic of TGCT.

Observation:

• A 45-year-old male presented with a six-month history of painful right hip swelling, initially misdiagnosed as Erdheim-Chester disease.
• Whole exome sequencing and RNA-sequencing identified a novel CSF1::GAPDHP64 fusion.
• Single-cell transcriptome analysis revealed neoplastic cells expressing CSF1 attracting macrophages.

Findings:

• The CSF1::GAPDHP64 fusion confirmed the diagnosis of Tenosynovial Giant Cell Tumor (TGCT).
• Treatment with pegylated interferon and imatinib resulted in stable disease.
• Ligand-receptor interaction analysis demonstrated significant communication between neoplastic cells and macrophages via CSF1/CSF1R signaling.

Implications:

• Comprehensive molecular analysis, including whole exome sequencing and RNA-sequencing, is crucial for accurate diagnosis of rare tumors like TGCT.
• Understanding the role of CSF1 in tumor cell-macrophage communication can inform future therapeutic strategies.
• Targeted therapies may offer effective management options for patients with TGCT.