Presented with cervical pain/a palpable thyroid nodule was found surrounded by enlarged lymph nodes/a high serum level of calcitonin and low calcium/elevated CEA/Histopathological examination demonstrated sheets of polygonal cells with the pseudo glandular arrangement and angioinvasion, 1 year after the surgery due to pancytopenia BMA was done and showed total infiltration composed of clumps of round to spindle cells separated by amorphous deposits positive tumor cells for calcitonin, chromogranin A and synaptophysin. Here, CEACAM5 is linked to neoplasm.