99m Tc-FAPI-46 Scintigraphy in Parotid Mucoepidermoid Carcinoma

Area of Science:

• Nuclear Medicine
• Oncology
• Radiochemistry

Background:

• Recurrent mucoepidermoid carcinoma (MEC) poses significant management challenges, particularly with metastatic disease.
• Conventional imaging modalities may underestimate the true extent of skeletal and extraskeletal metastases in MEC.
• Accurate staging is crucial for effective palliative care and treatment planning in advanced cancer.

Purpose of the Study:

• To evaluate the utility of 99mTc-FAPI-46 scintigraphy in assessing metastatic disease extent in a patient with recurrent MEC.
• To compare the diagnostic yield of FAP-targeted imaging against conventional bone scintigraphy (99mTc-MDP) and clinical presentation.
• To highlight the potential of 99mTc-FAPI-46 in identifying a greater disease burden and guiding patient management.

Main Methods:

• Case report of a 58-year-old female patient with recurrent right parotid MEC.
• Utilized 99mTc-MDP bone scintigraphy and palliative radiotherapy for symptom management.
• Performed 99mTc-FAPI-46 scintigraphy to assess metastatic disease following discordant clinical and initial imaging findings.

Main Results:

• 99mTc-MDP bone scintigraphy showed limited skeletal metastases, while palliative radiotherapy provided no symptom relief.
• 99mTc-FAPI-46 scintigraphy revealed a significantly greater disease burden, including multiple skeletal metastases, pulmonary involvement, and metastatic lymph nodes.
• The findings from FAP-targeted imaging were more extensive than suggested by conventional methods and clinical symptoms alone.

Conclusions:

• 99mTc-FAPI-46 scintigraphy demonstrates added value in detecting the full extent of metastatic disease in recurrent MEC.
• FAP-targeted imaging may provide comprehensive information beyond conventional modalities, especially in cases with discordant findings.
• This case suggests that 99mTc-FAPI-46 could be a valuable tool for staging and managing advanced MEC.