Giant cell tumour of soft tissue—a rare presentation of a common pathology

We present the case of a giant cell tumour of soft tissue (GCT-ST) presenting as a slow-growing paraspinal mass. Imaging investigations revealed a well-circumscribed subcutaneous lesion containing fluid–fluid levels and an internal solid nodule. The imaging findings resulted in only a tentative differential which included haematoma or complex epidermoid cyst but failed to provide a definitive diagnosis. The patient underwent an image-guided biopsy from which a histopathological diagnosis of a GCT-ST was made. GCT-ST is a primary soft tissue neoplasm that is clinically and histologically similar to giant cell tumour of bone. Given its rare occurrence, there is very little published literature on the characteristic imaging findings of GCT-ST to help with its diagnosis which is usually only made histologically. The aim of this case report is to highlight our specific imaging findings and add to the limited pre-existing imaging data on GCT-ST.