What is that Lump? - A Case Study
A lady of 69 years presented to the Nuclear Medicine department with an 18-month history of a large soft tissue mass located on the medial aspect of the right knee. Ultrasound images in conjunction with plain x-ray taken a month earlier suggested a differential diagnosis of a soft tissue neoplasm. Further investigations with MRI were performed a week prior to the bone scan and this showed a growing mass which measured 9.3 cm (anterior –posterior) x 6.2 cm (transverse) x 12.6 cm (superior-inferior) and was suggestive of a Baker’s cyst or haemangioma. A three phase bone scan was requested for confirmation and found a decreased region of activity during blood flow and pool images whilst there was mild non-specific increased uptake within the region on delayed images. This pattern of uptake can be seen in the presence of benign and malignant soft tissue tumours and more rarely in haemangiomas. Following histology reports tissue samples revealed the presence of a juxta-articular myxoma, a rare, benign tumour.