MUC5AC and neoplasm: Extracellular mucin production can also be seen; however, such foci need to be differentiated from invasive mucinous carcinoma.13 Mucinous carcinoma, Capella type B, characterized by large sheets of tumor cells with mucin production and neuroendocrine features, may resemble SPC to a large extent, especially when associated with less mucin production (≤50% mucinous component; a poor prognostic factor).14