Solitary fibrous tumor (SFT) is a rare tumor of mesenchymal origin that most commonly involves the pleura but can be found anywhere in the body. SFT can range from indolent benign tumors to aggressive malignant tumors, and pre-operative diagnosis is based mainly on imaging. In this case report, we describe an extremely rare case of SFT of left maxilla on F-18 FDG PET-CT and Ga-68 DOTANOC PET-CT. Very few cases of PET-CT findings in SFT are reported in literature; and to our knowledge, none involving the maxilla. By highlighting the findings on F-18 FDG and GA-68 DOTANOC PET-CT, we aim to further add on to the role of both the tracers in the diagnosis and management of this tumor group.

A 31-year-old Indian female with a history of near-total thyroidectomy 2.5-years prior presented with recurrent neck swelling. Magnetic resonance imaging (MRI) of the neck revealed an infiltrating mass involving the thyroid bed. Biopsy from the mass and review of slides from the previous thyroidectomy revealed a spindle cell tumour with interspersed areas of fibrosis and infiltrative edges entrapping thyroid follicles. Beta-catenin immunopositivity and CTNNB1 mutation confirmed the diagnosis of fibromatosis. The case is being reported for its rarity and the discussion of its differential diagnoses.
thyroid ; fibromatosis ; immunohistochemistry ; molecular ; Thyroid Nodule