Schmorl’s Node Mimicking Metastasis in a Patient With Breast Cancer: Diagnosis With 99mTC Methylene Diphosphonate SPECT-CT

Differentiation between spinal subchondral bone metastasis with focal pathologic endplate fracture and oedematous Schmorl's node

INTRODUCTION

We aimed to identify imaging-based findings that can differentiate between spinal subchondral bone metastasis with focal pathologic endplate fracture and oedematous Schmorl's nodes that have been histopathologically confirmed.

METHODS

Between March 2010 and April 2016, 11 patients who had undergone spinal magnetic resonance (MR) imaging or computed tomography (CT) with final radiologic reports that included 'subchondral bone metastasis with focal pathologic endplate fracture' or 'edematous Schmorl's node' and had also undergone percutaneous imaging-guided spinal biopsies were included. Two radiologists retrospectively evaluated the following imaging features in consensus: size, location, presence of sclerotic margin, presence of intralesional or perilesional enhancement and opposite endplate enhancement of the involved disc, presence of disc height loss and presence of metabolic uptake at a corresponding lesion on nuclear medicine imaging.

RESULTS

A total of 11 patients, including six patients with spinal subchondral bone metastasis with focal pathologic endplate fracture and five patients with oedematous Schmorl's nodes, were included in this study (median age, 58 years; range, 50-63 years; six men). Sclerotic margin (P = 0.002) and enhancement on the opposite endplate of the involved disc (P = 0.047) were significantly different between oedematous Schmorl's node and subchondral bone metastasis with focal pathologic endplate fracture.

CONCLUSION

Sclerotic margin and enhancement on the opposite endplate of the involved disc suggest oedematous Schmorl's node rather than subchondral bone metastasis with focal pathologic endplate fracture. Decreased disc height is likely to be an oedematous Schmorl's node rather than subchondral bone metastasis with focal pathologic endplate fracture.

Papillary Thyroid Carcinoma Metastasis to the Lumbar Spine Masquerading as a Schmorl's Node

A Schmorl's node is a common incidental finding encountered during radiologic imaging. Despite the vertebral body being a common site of metastatic disease, a lytic lesion adjacent to an endplate with typical imaging features can often confidently be called a Schmorl's node. This is a case report of a patient with a single well-defined FDG-avid papillary thyroid carcinoma metastasis to the spine that had imaging findings characteristic of a Schmorl's node on CT and MRI. This case is important to consider as it demonstrates that the imaging characteristics of metastatic disease and Schmorl's nodes can overlap.