<prompt> A 40-year-old male presented with a thyroid swelling and dysphagia. He gave history of on and off watery diarrhea. Biopsy of the lesion is shown. What is your diagnosis?Follicular Ca thyroidPapilllary Ca thyroidMedullary Ca thyroidAnaplastic cell Ca Thyroid  <response>: Ans. c Medullary Ca thyroidDiarrhea in thyroid tumor can be a paraneoplastic syndromes due to VIP in a case of medullary Ca thyroid. Histology demonstrates abundant deposition of amyloid, visible here as homogeneous extracellular material, derived from calcitonin molecules secreted by the neoplastic cells. 