Paget′s disease of pelvis mimicking metastasis in a patient with lung cancer evaluated using staging and follow-up imaging with fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography

Abstract

Paget's disease of bone is a benign disease, of uncertain etiology, characterized by an accelerated turnover, that is, bone resorption and formation. Paget's disease may be present in up to 5% of the population, and the majority of cases are asymptomatic. We report the imaging findings of Paget's disease of pelvis discovered incidentally in patient with lung cancer evaluated by fluorine-18-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for staging. FDG PET-CT scan showed intense uptake in the right lung lower lobe primary and mediastinal lymph nodes. Furthermore, increased uptake noted in left hemipelvis suggestive of Paget's disease. He underwent follow-up FDG PET-CT after chemotherapy showed decrease in lung mass and mediastinal nodes. However, the uptake in left hemipelvis remains same confirming Paget's disease.

Benign Bone Conditions That May Be FDG-avid and Mimic Malignancy

“…23), which may mimic metastatic bone disease when typical anatomical changes are absent. [126][127][128] Note that about 1% of cases of Paget disease of bone undergo sarcomatous change 129 and that FDG-PET alone is not able to differentiate the former from the latter.…”

Is paget disease of bone more common in South India? Clinical characteristics, therapeutic outcome and follow-up of 66 patients from Tamil Nadu

“… A cartoon of the number of published case reports/series on Paget Disease of Bone from India from Pubmed and Google Scholar from 1963 to 2019. [ 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 ] The size of the dots is representative of the number of case reports from that state. Size expressed as a fraction (0.1cm X Number of cases) and for purpose of rep-resentation, the largest representation is shown as Square root of (0.1cm X Number of cases) …”

Incidental Paget’s Disease Disguised as Bone Metastasis in a Patient with Endometrium Carcinoma

“…Although Technetium scan is more useful and cost effective in the diagnosis of PDB in our case the diagnosis was established incidentally based on high uptake in FDG-PET imaging which was performed due to the presence of malignancy (18). F-FDG PET/CT imaging may be helpful in the differential diagnosis of bone metastasis and PDB in patients with malignancy (5). As the 18F-FDG enters the osteoblasts proportional with increased bone mineralisation and enhanced glycolisis, PDB demonstrates a variable FDG uptake pattern in the osseous lesions for any individual patient, possibly due to the differences in the rate of bone remodelling.…”