How is small-cell cancer of the pancreas diagnosed?

Question

Hello doctor,

Recently, I was diagnosed with small-cell carcinoma of the pancreas. INSM1, CK Oscar, and Synaptophysin were stained positively. CD45 was negative. The pathology report does not include a grade or a Ki67 value. Is this normal?

What are some possible differential diagnoses that this could be (outside of small cell carcinoma) that would have positive stains for these? We suspect that the diagnosis may be inaccurate and want to know what other cancers could stain positive for these.

Thanks.

Answer 1

Hello,

Welcome to icliniq.com.

I can understand your concern.

I understand your apprehension and will definitely try to help you out.

Primary small cell carcinoma of the pancreas is a rare malignancy with a poor prognosis, which accounts for 1 to 1.4 per cent of all pancreatic malignancies. INSM1 is a nuclear marker of neuroendocrine differentiation with equivalent or better sensitivity and specificity compared to synaptophysin. It is expressed in 100 percent of pancreatic neuroendocrine tumors. Positive INSM1, along with positive synaptophysin, strongly indicate a small cell neuroendocrine tumor.
Small cell carcinomas, by definition, are aggressive neoplasms, and around 91 % have metastases at the time of initial diagnosis. An elevated serum NSE (neuron-specific enolase) level can also help you confirm the diagnosis. You can still get the Ki67 index done on the remaining tissue, and you can still get the diagnosis reviewed at another center if you have doubts. In my opinion, a thorough search for metastatic deposits should be done at this stage, and treatment (chemo or radiation) should be started as soon as possible.

I hope this information will help you.

Thanks.