There are several histologic variants of MTC including tubular (follicular), papillary, small cell, giant cell, clear cell, melanotic (pigmented), oncocytic (oxyphilic), squamous, amphicrine (composite calcitonin- and mucin-producing), and paraganglioma-like variants [1,2,3]. Here, MUC5AC is linked to medullary thyroid gland carcinoma.