Pulmonary Artery Sarcoma With Low 18F-FDG Uptake

Abstract

A 75-year-old man presented with dyspnea for more than 2 months, with blood test showing low platelet count and cardiac ultrasound showing severe pulmonary hypertension (>54 mm Hg). A CT pulmonary angiogram showed a filling defect in the pulmonary trunk, right and left pulmonary arteries, raising the possibilities of pulmonary embolism or artery sarcoma. FDG PET/CT was performed for further evaluation and showed low uptake in the pulmonary wall, which supported the diagnosis of pulmonary embolism. Patient was treated with anticoagulants with no changes on repeated CT pulmonary angiogram. Patient underwent surgery, and histopatological examination revealed a pulmonary artery sarcoma.

68Ga-FAPI-04 Versus 18F-FDG PET/CT in a Case With Intimal Sarcoma of the Pulmonary Artery

“…2 Although pulmonary artery sarcoma usually shows higher FDG uptake than thromboembolism, 3,4 it may show low FDG uptake probably due to low cellularity and the presence of myxoid matrix and necrosis, mimicking thromboembolism. [7][8][9][10] Several case reports and articles have shown the usefulness of FAPI PET in the detection and staging of sarcoma. 6,[11][12][13][14][15] A prospective study showed 68 Ga-FAPI PET was a valuable diagnostic tool in patients with sarcoma and had a high positive predictive value and sensitivity for sarcoma staging.…”

“…Intimal sarcoma of the pulmonary artery is a rare malignant tumor mimicking pulmonary thromboembolism clinically and radiologically 2. Although pulmonary artery sarcoma usually shows higher FDG uptake than thromboembolism,3,4 it may show low FDG uptake probably due to low cellularity and the presence of myxoid matrix and necrosis, mimicking thromboembolism [7][8][9][10]. Several case reports and articles have shown the usefulness of FAPI PET in the detection and staging of sarcoma 6,[11][12][13][14][15].…”

Pulmonary Artery Angiomatoid Fibrous Histiocytoma Mimicking a Large Pulmonary Embolism

“…On 18 F-FDG PET/CT, AFH was commonly hypermetabolic 5,7. The differential diagnosis of pulmonary artery AFH includes septic PE, pulmonary artery fibrous tumor, sarcoma, and so on 2,3,5. Microscopically, a thick fibrous pseudocapsule, infrequent mitoses, blood-filled endothelial-lined cystic cavities, and a rim of dense lymphoplasmacytic infiltrate suggest the diagnosis 8,9.…”

“…5,7 The differential diagnosis of pulmonary artery AFH includes septic PE, pulmonary artery fibrous tumor, sarcoma, and so on. 2,3,5 Microscopically, a thick fibrous pseudocapsule, infrequent mitoses, blood-filled endothelial-lined cystic cavities, and a rim of dense lymphoplasmacytic infiltrate suggest the diagnosis. 8,9 Fluorescence in situ hybridization analysis revealed rearrangement of EWSR, which was confirmed by RT-PCR as EWSR1-ATF1 fusion.…”

“…A (bottom row), Ventilatory images with Xenon-133 at equilibrium phase were normal. Although large pulmonary embolism (PE) could not be excluded, a central mediastinal or pulmonary artery tumor causing a unilateral lung multilobe perfusion defect was considered 1–3 . B , CT pulmonary angiogram revealed a minimally enhancing large mass lesion completely occluding the right interlobar pulmonary artery (white arrow).…”