Primary lymphoma of iliac bone

A 86-year-old male presented with weight loss of 7 kg and right groin pain of 2 months duration. Computed Tomography (CT) demonstrated an ill-defined osteolytic permeative lesion involving the right iliac bone with adjacent soft tissue mass (Fig. A, white arrow).Subsequent Magnetic Resonance Imaging (MRI) clearly showed the osseous origin of the lesion with huge surrounding soft tissue mass, wrapping around the right iliac bone. The lesion was of low signal intensity (SI) on T1-Weighted Images (WI) and of relatively low SI on T2-WI (Fig. B, white arrow). After intravenous administration of gadolinium contrast, there was significant enhancement of the bony lesion and surrounding soft tissue mass, with areas of central necrosis (Fig. C, asterisk). The differential diagnosis on imaging, according to the patient age, included metastasis, plasmacytoma and lymphoma. Further staging of the patient was negative for any primary malignancy. Biopsy of the iliac bone and subsequent histological examination revealed clusters of small to large lymphocytes, with a variable nucleocyto - plasmic ratio, in keeping with a primary large cell Non-Hodgkin’s lymphoma of bone (Fig. D). The patient was scheduled for chemo-radiotherapy treatment.