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.

Immunoglobulin G4 (IgG4)–related diseases are a spectrum of systemic inflammatory conditions of unknown etiology, which are characterized by infiltration of tissues by IgG4 plasma cells and sclerosing inflammation (Cheuk and Chan Adv Anat Pathol 17:303-32, 2010). Although this condition was initially described in relation to autoimmune pancreatitis, now it has been reported in almost every organ system of body (Zen and Nakanuma Am J Surg Pathol 34:1812-9, 2010, Masaki et al. Ann Rheuma Dis 68:1310-5, 2009). Orbital involvement by IgG4 disease can involve extraocular muscles (EOM), lacrimal glands, conjunctiva, eyelids, infraorbital nerve, orbital fat, and nasolacrimal system (McNab and McKelvie. Ophthal Plast Reconstr Surg 31:167-78, 2015, Katsura et al. Neuroradiology 54:873-82, 2012). The basis of using ⁶⁸Ga-DOTANOC PET/CT in IgG4 orbital disease is the known expression of somatostatin receptors in chronic inflammatory cells (Cuccurullo et al. Indian J Radiol Imaging 27:509-16, 2017) and also avidity shown previously in other IgG4-related diseases (Cheng et al. Clin Nucl Med 43:773-6, 2018).
Conjunctiva ; Eyelids ; Immunoglobulin G ; Immunoglobulins ; Inflammation ; Lacrimal Apparatus ; Muscles ; Orbit ; Orbital Diseases ; Pancreatitis ; Plasma Cells ; Positron-Emission Tomography and Computed Tomography ; Receptors, Somatostatin

Immunoglobulin G4 (IgG4)–related diseases are a spectrum of systemic inflammatory conditions of unknown etiology, which are characterized by infiltration of tissues by IgG4 plasma cells and sclerosing inflammation (Cheuk and Chan Adv Anat Pathol 17:303-32, 2010). Although this condition was initially described in relation to autoimmune pancreatitis, now it has been reported in almost every organ system of body (Zen and Nakanuma Am J Surg Pathol 34:1812-9, 2010, Masaki et al. Ann Rheuma Dis 68:1310-5, 2009). Orbital involvement by IgG4 disease can involve extraocular muscles (EOM), lacrimal glands, conjunctiva, eyelids, infraorbital nerve, orbital fat, and nasolacrimal system (McNab and McKelvie. Ophthal Plast Reconstr Surg 31:167-78, 2015, Katsura et al. Neuroradiology 54:873-82, 2012). The basis of using ⁶⁸Ga-DOTANOC PET/CT in IgG4 orbital disease is the known expression of somatostatin receptors in chronic inflammatory cells (Cuccurullo et al. Indian J Radiol Imaging 27:509-16, 2017) and also avidity shown previously in other IgG4-related diseases (Cheng et al. Clin Nucl Med 43:773-6, 2018).