CASE 10987 Published on 11.12.2013

Pelvic lymphoma

Section

Musculoskeletal system

Case Type

Clinical Cases

Authors

G. Feutry G, Arditi D

Switzerland;
Email: daniel.arditi@hcuge.ch,
gregoire.feutry@hcuge.ch
Patient

71 years, female

Categories
Area of Interest Musculoskeletal soft tissue, Musculoskeletal bone, Bones ; Imaging Technique CT, PET-CT, Conventional radiography, MR
Clinical History
A 71-year-old woman known for diabetes mellitus consulted her general practitioner for painless limping that started a month earlier. He requested a pelvic radiograph that revealed a comminuted fracture of the left iliac bone and ilio-pubic branch.
Imaging Findings
An 18-FDG PET-CT revealed a large permeative lytic mass in the left iliac wing measuring 17.7 x 11.1 x 18 cm with avid uptake of the radiotracer and max SUV measured of 18.9 (Fig. 2). Other hypermetabolic lesions were discovered in the cervical and abdominal nodes, in the right iliac wing and in the L4 vertebra. Fractures of the left iliac bone, acetabulum and ilio-pubic branch were confirmed.
An MRI shows a large mass centred on the left iliac wing, with intrapelvic extension. After injection, it showed intense contrast enhancement except for a central necrotic region (Fig. 3). The diffusion maps demonstrated a decrease in the ADC value (0.78) in favour of a high cellularity.
The final diagnosis, large B-cell lymphoma, was detected by CT-guided biopsy.
Discussion
There are two main categories of bone lymphomas: systemic bone lymphomas, with secondary involvement of bone and primary bone lymphoma, which is defined by a presentation with an osseous site with no evidence of disease elsewhere for at least 6 months after diagnosis (suggested by Coley in 1950) [1].
Non-Hodgkin lymphoma (NHL) represents 85 to 90 % of all lymphomas [1]. Bone involvement appears in more than 25% of patients with NHL and is rarely present at the onset of the illness. NHL can arise at any age but is more frequent in patients in the sixth and seventh decade. Men are also more at risk (sex ratio 1.5:1) [2].
Symptoms are insidious with pain, local swelling and sometimes a palpable mass. Systemic B symptoms may occur.

From a radiologic perspective, different types of lesions have been identified in NHL [1]:
Lytic-destructive pattern is the most common appearance, with cortical breakthrough. Periosteal reaction is frequent and may be either lamellated or layered. Extension in the soft tissues is common, usually well tolerated and regarded as a negative prognostic factor.
The second pattern is the blastic-sclerotic pattern, which is more often seen in metastatic bone lymphoma than in primary bone lymphoma. Mixed lesions with lytic areas can be seen.
The third pattern is the “near normal” findings on conventional radiographs, which can show abnormalities on scintigraphy or MRI. Patient with suggestive symptoms and normal radiographic findings should be investigated further.
MRI allows us to evaluate the invasion of bones and soft tissues. Bone marrow changes will appear with low signal intensity on T1, contrast enhancement and usually high signal intensity on T2 [1, 3]. MRI can also highlight subtle linear intra-cortical defects, which are hyperintense in T2 and demonstrate tumoral extension by cortical tunnelling.

Our patient was then treated by CHOP chemotherapy in association with Rituximab and radiotherapy in order to decrease her pain. Surgery and complete hip prosthesis were rejected because of infection and unsealing risks.
Differential Diagnosis List
Pelvic bone lymphoma
Metastasis
Ostemyelitis
Myeloma
Osteosarcoma
Final Diagnosis
Pelvic bone lymphoma
Case information
URL: https://www.eurorad.org/case/10987
DOI: 10.1594/EURORAD/CASE.10987
ISSN: 1563-4086