Not to be confused with “carcinoma of unknown primary,” in this episode of metastatic disease of “origin TBD”, we discuss the workup of a mass noted incidentally on imaging. This is a very high yield topic often faced on solid oncology consults! Major Points Covered:Mass found incidentally on imaging → we need to stage alwaysInitial Workup:Reasonable to get CBC, CMP, UA, PSA (if male)Low blood counts, maybe marrow involvementCr elevated concern for obstruction possiblyLFTs elevated concern for mass in the biliary/pancreas regionUA w/ hematuria → maybe bladderBut bottom line you’re gonna get a scan, which scan to get though?Recommend referencing NCCN guidelines to determine additional staging scansCreate an account on nccn.org and look at guidelines by tumor typeNot all cancers require a PET/CT scanThere are newer modalities for imaging other than FDG PET including PSMA PET (prostate), Auxumin PET (prostate), and DOTATE PET (neuroendocrine)Certain cancers can be diagnosed on imaging alone (RCC and HCC)Some cancers require Brain MRI for stagingWhat to biopsy?FNA often adequate for solid tumors but may need core if non diagnostic Need core or ideally excisional if highly concerned for lymphomaAlways try to biopsy the site that will upstageDistant lymph nodes or other metastatic sitesWhat about tumor markers?We use this for treatment monitoring, not for diagnostic purposesImportant to establish a baseline to follow, special circumstances for diagnostic purposes to consider below:PSA in male if concerned about prostate cancerAFP helpful if concerned for HCC → liver masses in a cirrhoticAFP and b-HCG if concerned for testicular → young or middle aged male with mediastinal massMolecular testing not necessarily needed at the time of biopsy Please visit our website (TheFellowOnCall.com) for more information Twitter: @TheFellowOnCallInstagram: @TheFellowOnCallListen in on: Apple Podcast, Spotify, and Google Podcast