[en] A case of carcinomatous monoarthritis involving the left knee due to colonic
adenocarcinoma is described. Large recurrent synovial effusion, that will be
later hematic, lytic lesion of the bones and chondrolysis were noted. Knee
positron emitting tomography scan using FDG (FDG-PET) revealed a diffuse
increased uptake in soft tissues assumed to be synovium, the hypertrophy of which
was identified by ultrasonography. Whole body PET scan showed extensive lymph
node, visceral and bone metastases, suggesting that the increase in the synovium
could also be of metastatic origin. The final diagnosis of synovial
carcinomatosis secondary to the known colonic adenocarcinoma was confirmed by
histological analysis of biopsies obtained by arthroscopy. A review of the
literature is realised. To our knowledge, this is the first synovial metastasis
studied by FDG-PET.
