We found 65 cases of adult PBL not FAP-related; thus, 7 out of 65 cases (10.7%) of adult PBL reported in the literature are associated with a clinical diagnosis of FAP or were carriers of <i>APC</i> germline pathogenic variants (GPVs).<h4>Conclusion</h4>Data suggest a non-random association between adult PBL and FAP. Here, APC is linked to Familial adenomatous polyposis.