Faculty Bibliography

Familial adenomatous polyposis (FAP) is an autosomal dominant syndrome associated with mutation in the adenomatous polyposis coli (APC) gene, a tumour suppressor located on chromosome 5q21. Attenuated familial adenomatous polyposis (AFAP) is a variant associated with fewer and later onset of colon polyps. AFAP-associated APC mutations have largely been found before codon 157, in exon 9 or after codon 1595. We present the case of a 44-year-old man incidentally found to have numerous gastric polyps during bariatric surgery, with innumerable polyps in the remaining part of the stomach and the entire colon, with rectal sparing, consistent with AFAP phenotype. Genetic testing demonstrated the c.7682dup (p.Ser2562Lysfs*21) variant in exon 15 of APC. This represents a previously undescribed APC mutation. This mutation likely yields end-binding protein 1 and human disc large binding protein inactivation, causing cell cycle microtubule dysregulation and tumour suppressor inactivation. Through loss of these regulatory mechanisms, this mutation is associated with AFAP phenotype. The patient was treated surgically and is doing well.

OBJECTIVES/OBJECTIVE:To investigate the diagnostic potential of AEG-1 and GPC-3 in hepatocellular carcinoma (HCC). METHODS:AEG-1 and GPC-3 immunohistochemistry were performed on HCC, adjacent nontumor tissue (ANT), and dysplastic nodules (DN). RESULTS:H score of AEG-1 or GPC-3 in HCC was significantly higher than in ANT or DN. In HCC, 92% and 54% showed AEG-1 and GPC-3 positivity, respectively. In ANT, 16.2% were AEG-1 and 7.6% GPC-3 positive. AEG-1 staining was mostly diffuse, whereas GPC-3 frequently showed focal staining. AEG-1 alone showed high sensitivity but low specificity and accuracy. GPC-3, on the other hand, showed high specificity but low sensitivity and accuracy. Combination of both stains boosted the sensitivity, specificity, and accuracy to 94.6%, 89.5%, and 90.5%, respectively, when only diffuse staining was considered as positive. CONCLUSIONS:AEG-1 or GPC-3 alone seemed not an ideal marker for HCC. The combination of AEG-1 and GPC-3 might improve early diagnosis of HCC.

Histoplasmosis is a self-limited and asymptomatic disease in immunocompetent individuals. Patients with untreated human immunodeficiency virus (HIV) or immune suppression due to medications such as corticosteroids can present with disseminated and life-threatening infections. We present a case of a 60-year-old female that presented with recurrent diarrhea that was found to have isolated gastrointestinal (GI) histoplasmosis. The rarity of this case is due to the isolated colonic involvement and lack of respiratory symptoms (the portal of infection). In conclusion, clinicians should be aware of isolated histoplasmosis affecting the GI tract and careful endoscopic evaluation with adequate sampling is warranted to confirm the diagnosis.