title: Coexisting tubular adenoma with a neuroendocrine carcinoma of colon allowing early surgical intervention and implicating a shared stem cell origin.
abstract: High-grade colonic neuroendocrine carcinomas (NECs) are uncommon but extremely aggressive. Their co-existence with tubular adenoma (TA) has rarely been reported. We present a 68-year-old man who was found on routine colonoscopy to have multiple colorectal TAs and an ulcerated lesion in the ascending colon. Microscopically, a poorly-differentiated invasive carcinoma juxtaposed with a TA was identified. Differential diagnosis included a poorly-differentiated adenocarcinoma, medullary carcinoma, high-grade NEC and lymphoma. The immunohistochemical profile showed positive staining for keratins, synaptophysin and chromogranin but negative for LCA, CDX2, CK7, CK20, TTF-1 and PSA, supporting the NEC diagnosis. Upon subsequent laparoscopic right hemicolectomy, the tumor was identified as a 3.0 cm umbilicated and ulcerated mass with an adjacent TA. Both TA and NEC showed positive staining for β-catenin indicating a shared colonic origin. The mitotic counts (77/10 high power fields) and a high proliferation rate (75% by Ki-67) corroborated a high-grade stratification. Mutational analysis indicated a wild-typeBRAFandKRASwith mismatch repair proficiency. The AJCC (7thedition) pathologic stage is pT3, pN0, pMx. The patient received adjuvant chemotherapy with cisplatin/etoposides for three cycles and will be followed up for a year to detect recurrence. In conclusion, the co-existence of TA with high grade-NEC in our case allowed early identification and intervention of the otherwise asymptomatic but aggressive tumor. In addition, the finding of a high-grade NEC within a large TA in this case suggests a link between the two lesions and could represent a shared stem cell origin.
authors.affiliation: Mahmoud L Soliman, Qing Zhao, Department of Pathology and Laboratory Medicine, Boston University Medical Center, Boston, MA 02118, United States.
authors.forename: Mahmoud L
authors.initials: ML
authors.lastname: Soliman
authors.affiliation: Mahmoud L Soliman, Qing Zhao, Department of Pathology and Laboratory Medicine, Boston University Medical Center, Boston, MA 02118, United States.
authors.forename: Ashish
authors.initials: A
authors.lastname: Tiwari
authors.affiliation: Mahmoud L Soliman, Qing Zhao, Department of Pathology and Laboratory Medicine, Boston University Medical Center, Boston, MA 02118, United States.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhao
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000473:pathology; D000236:Adenoma / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology / Q000628:therapy; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D018276:Carcinoma, Medullary / Q000175:diagnosis* / Q000473:pathology; D018278:Carcinoma, Neuroendocrine / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology / Q000628:therapy; D017024:Chemotherapy, Adjuvant; D003082:Colectomy / Q000379:methods; D003106:Colon / Q000473:pathology; D003110:Colonic Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology / Q000601:surgery; D003113:Colonoscopy; D004252:DNA Mutational Analysis; D003937:Diagnosis, Differential; D006801:Humans; D007150:Immunohistochemistry; D008223:Lymphoma / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local; D014411:Neoplastic Stem Cells / Q000378:metabolism*; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics; D013964:Thyroid Neoplasms
chemical_list: D014408:Biomarkers, Tumor; C117307:KRAS protein, human; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D016283:Proto-Oncogene Proteins p21(ras)
keywords: Colocalization; Colorectal; Neuroendocrine carcinoma; Tubular adenoma