title: False-positive uptake of TI-201 by an intracranial inflammatory pseudotumor.
abstract: A 28-year-old man had recurrent episodes of headache, ophthalmoplegia, and ptosis. MR imaging showed a mass within the sphenoid sinus. TI-201 imaging showed intense uptake in the region of the sphenoid sinus and right middle fossa with moderate retention of activity, suggesting the diagnosis of a viable tumor. A biopsy specimen from the sphenoid sinus revealed dense inflammatory infiltrate dominated by plasma cells, consistent with inflammatory pseudotumor. After radiation therapy, the mass showed no significant change on MR imaging, but regressed in size and uptake on the follow-up TI-201 scan. TI-201 may accumulate in nonmalignant inflammatory lesions and could mimic a viable tumor. It is, therefore, suggested that before surgery and histologic diagnosis, any abnormal intracranial accumulation of TI-201 should be interpreted with caution.
authors.affiliation: Division of Nuclear Medicine, Mount Sinai School of Medicine, City University of New York, New York, USA.
authors.forename: M
authors.initials: M
authors.lastname: Lorberboym
authors.forename: M
authors.initials: M
authors.lastname: Sacher
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D005189:False Positive Reactions; D006104:Granuloma, Plasma Cell / Q000175:diagnosis / Q000000981:diagnostic imaging*; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010254:Paranasal Sinus Diseases / Q000175:diagnosis / Q000000981:diagnostic imaging; D013101:Sphenoid Sinus / Q000000981:diagnostic imaging / Q000473:pathology; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D013794:Thallium Radioisotopes