Neuro endocrine carcinomas (NECs) are rare and high-grade (3) neuroendocrine neoplasms that arise from various organs.
Makes up 18% of neuroendocrine tumors.
Neuroendocrine carcinomas occur in patients who are younger and more likely to have functional tumors, 14% versus 2%, with neuroendocrine tumors.
Mutations in MEN1, DAXX, and ATRX are seen in pancreatic NET, G3 lesions, whereas, RB1, KRAS, and TP53 mutations are common in poorly differentiated NEC’s.
The most common primary organ of a grade 3 neuroendocrine tumor is the pancreas at 65%.
The prognosis of NECs in advanced disease is reported to be 8 to 13 months.
A grading scheme based on mitotic counts of KI 67 classified neuroendocrine neoplasms into grades one through three.
Grade 3 is composed of tumors with more than 20 mitoses per high powered fields or a KI 67 index greater than 20%.
NEC tumors are grade 3.
Most grade 3 tumors have poorly differentiated features.
NET G3 generally staying positive for synaptophysin, and chromogranin, 97% and 91%, respectively.
Other markers include insulinoma associated proteins 1 are being used.
NET G3 stains positively for somatostatin receptor type 2A and has abnormal nuclear p53 and RB1 staining.
NET G3 often show avidity for PET scans, whereas NET G1, and G2 frequently do not.
Neuroendocrine cancers have a higher rate of FDG avidity on PET scan.
Neuroendocrine carcinomas (NEC) which is poorly differentiated by definition accounts for 5 to 10% of neuro endocrine neoplasms.
Small cell neuroendocrine carcinomas are most prevalent in the lung and strongly related to smoking.
NEC typically stains positive for synaptophysin but negative with chromogranin.
NEC tends to demonstrate abnormal staining of p53 inland RB1 one and SSTRA staining is absent.
NEC has a poor prognosis in general, with the overall five-year relative survival rate of 38% among patients with local/regional disease and 7% among those with extensive disease.
Small cell NEC histology is associated with worst median five-year survival at most primary sites.
Etoposide, cisplatinum, irinotecan, streptozotocin, temozolomide, fluouracil, capecitabine, emerolimus, sunitinib, somatostatin analogues and peptide receptor radionuclides(Luteum177) -are agents with efficacy in advanced neuroendocrine carcinomas.