18F-fluoride (18F-NaF) uptake in soft tissue metastases of medullary thyroid carcinoma (MTC) has been reported. However, the evolution of these metastatic sites has rarely been assessed. We present a case of 18F-NaF uptake in multiple liver metastases of MTC initially without macroscopic calcification. The CT follow-up studies showed a progressive calcium deposition in the lesions. Therefore, this case suggests that the 18F-NaF uptake in MTC metastases could potentially be a marker of an ongoing calcification process instead of an inert deposit of calcium.
From the *Division of Nuclear Medicine, São Paulo Cancer Institute (ICESP); and
†University of São Paulo Medical School (FMUSP), São Paulo, Brazil.
Received for publication June 26, 2018; revision accepted July 19, 2018.
Conflicts of interest and sources of funding: none declared.
Correspondence to: Paulo Schiavom Duarte, MD, PhD, Division of Nuclear Medicine, São Paulo Cancer Institute (ICESP), Doutor Arnaldo Ave, N° 251, 4° SS, Cerqueira César, São Paulo, Brasil 01246-000. E-mail: firstname.lastname@example.org.