In which breast cancer subtype is FDG PET-CT known to have relatively poor lesion conspicuity, making negative PET findings unreliable for axillary assessment?

• A Invasive ductal carcinoma, grade 3, triple negative
• B Inflammatory breast carcinoma with dermal lymphatic invasion
• C HER2-enriched ductal carcinoma with high Ki-67
• D Invasive lobular carcinoma ✓

Explanation

Invasive lobular carcinoma typically shows low cellular FDG avidity and grows diffusely without a nodular mass, producing frequent false-negative PET studies even for sizeable primary tumours and nodal disease. High-grade ductal carcinomas, especially triple negative and HER2-enriched tumours with high proliferation indices, are strongly FDG avid, as is inflammatory carcinoma. Recognising this limitation prevents inappropriate exclusion of nodal disease based on a negative PET in lobular histology.

Reference: Grainger and Allison's Diagnostic Radiology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.