Which thyroid carcinoma is associated with calcitonin amyloid deposition?

Ans. (d) Medullary(Ref: Robbins 9th/pg 260; 8th/pg 253)Microscopically, medullary carcinomas:Composed of polygonal to spindle-shaped cells, which may form nests, trabeculae, and even follicles.Acellular amyloid deposits, derived from altered calcitonin polypeptides, are present in the adjacent stroma in many cases.Calcitonin is readily demonstrable within the cytoplasm of the tumor cells as well as in the stromal amyloid by immunohistochemical methods.