PET/CT imaging of metastatic deposit in vertebral Paget's disease

An update on imaging of Paget's sarcoma

Paget's sarcoma is a rare and particularly aggressive tumour arising within pagetic bone, affecting approximately 1% of patients with Paget's disease during the course of their disease. Most of these tumours are osteosarcomas, but the age profile, skeletal distribution and clinical outcomes differ considerably from conventional osteosarcoma. In this review, we outline the clinical, radiographic/CT, scintigraphic and magnetic resonance imaging features of Paget's sarcoma. We also review the neoplastic and non-neoplastic mimics of Paget's sarcoma that should be considered in the differential diagnosis when encountering an aggressive lesion within pagetic bone.

Skeletal Metastases and Benign Mimics on NaF PET/CT: A Pictorial Review

OBJECTIVE

The aim of this article is to present examples in which sodium fluoride labelled with ¹⁸F (NaF) bone PET/CT would be a useful adjunct to guide complex clinical decisions about the staging, restaging, and treatment approach for patients with skeletal metastases and benign causes of NaF activity that can be mistaken for bone metastases. We present a pictorial review of selected cases of this cohort of patients.

CONCLUSION

NaF PET/CT hybrid fusion imaging is extremely useful in identifying potential causes of pain in patients with malignancies that have an affinity for skeletal metastases. This technique can help detect bone metastases, in problem solving, and to direct appropriate management.

Paget sarcoma of the pelvic bone with widespread metastatic disease on radiography, CT, MRI, and 18F-FDG PET/CT with pathologic correlation

We report a case of Paget sarcoma of the left superior pubic ramus and disseminated metastatic disease in a 70-year-old man. Paget disease of the left hemipelvis with malignant degeneration in the region of the left superior pubic ramus was initially diagnosed on radiographs. Subsequent CT, MRI, PET/CT imaging, and CT-guided biopsy confirmed the diagnosis and showed extensive left-sided pelvic and abdominal lymphadenopathy with widespread metastatic disease to liver, spleen, and lungs.

A progressive translational mouse model of human valosin-containing protein disease: the VCP(R155H/+) mouse

INTRODUCTION

Mutations in the valosin-containing protein (VCP) gene cause hereditary inclusion body myopathy (IBM) associated with Paget disease of bone (PDB), and frontotemporal dementia (FTD). More recently, these mutations have been linked to 2% of familial amyotrophic lateral sclerosis (ALS) cases. A knock-in mouse model offers the opportunity to study VCP-associated pathogenesis.

METHODS

The VCP(R155H/+) knock-in mouse model was assessed for muscle strength and immunohistochemical, Western blot, apoptosis, autophagy, and microPET/CT imaging analyses.

RESULTS

VCP(R155H/+) mice developed significant progressive muscle weakness, and the quadriceps and brain developed progressive cytoplasmic accumulation of TDP-43, ubiquitin-positive inclusion bodies, and increased LC3-II staining. MicroCT analyses revealed Paget-like lesions at the ends of long bones. Spinal cord demonstrated neurodegenerative changes, ubiquitin, and TDP-43 pathology of motor neurons.

CONCLUSIONS

VCP(R155H/+) knock-in mice represent an excellent preclinical model for understanding VCP-associated disease mechanisms and future treatments.

Paget's Disease. A Case Report

Paget's disease (PD) is a common focal progressive osteometabolic disorder characterised by a disturbance in bone modelling and remodelling, because of an increase in osteoblastic and osteoclastic activity. It is a condition of unknown aetiology affecting approximately 3% of the population over 40 years of age and, approximately 10% of those over the age of 85 years. It is most common in Northern Europe and Australia and is rare in Asia and Africa. We describe the case of a 71-year-old man diagnosed with PD confined to the sacrum. After laboratory test, an imaging study with radiography, scintigraphy, computed tomography (CT) and magnetic resonance imaging (MRI) was performed disclosing findings compatible with Paget's disease in middle pathologic phase. The diagnosis was confirmed at biopsy. The structural modification of the sacrum with spongiosa rarefaction, thickening of bone and intact bone cortical, confirmed by CT, are tipical of an intermediate phase of PD. This was also supported by signal MRI changes showing substitution of the red by the fat medulla, visualized by FS sequences. Once the treatment for the bone disease was established, the patient no longer complained of pain. Special attention should be paid to male and elderly patients with pain in the lumbar spine because of the potential risk cancer development (21). The radiologist must be attentive to the possible presentations and complications of PD, even in uncommon sites, trying whenever possible to correlate the radiological features with the patient's clinical symptoms.

The spine in Paget's disease

Paget's disease (PD) is a chronic metabolically active bone disease, characterized by a disturbance in bone modelling and remodelling due to an increase in osteoblastic and osteoclastic activity. The vertebra is the second most commonly affected site. This article reviews the various spinal pathomechanisms and osseous dynamics involved in producing the varied imaging appearances and their clinical relevance. Advanced imaging of osseous, articular and bone marrow manifestations of PD in all the vertebral components are presented. Pagetic changes often result in clinical symptoms including back pain, spinal stenosis and neural dysfunction. Various pathological complications due to PD involvement result in these clinical symptoms. Recognition of the imaging manifestations of spinal PD and the potential complications that cause the clinical symptoms enables accurate assessment of patients prior to appropriate management.