(18)F-Fluorine-18-l-dihydroxyphenylalanine ((18)F-DOPA) positive isolated peritoneal carcinomatosis from a MENII-related medullary thyroid carcinoma. About an atypical metastatic site and utility of (18)F-FDOPA.

A patient, operated for a medullary thyroid carcinoma (MTC) with a positive RET mutation, showed several peritoneal nodes on a computed tomography (CT), with increased Thyrocalcitonine. A (18)F-Fluorine-18-l-dihydroxyphenylalanine (18-F-FDOPA) positron emission tomography (PET/CT) showed isolated tracer uptake on the nodes. A biopsy confirmed that it was from the MTC, with the same RET mutation as in blood.