Skeletel radiology

Pepperpot skull :

(hungarian -borsszoro),

MM is the most common primary bone tumor in adults

Multiple myeloma must be included in the differential diagnosis of any lytic bone lesion, whether well-defined or ill-defined in age > 40. The most common location is in the axial skeleton (spine, skull, pelvis and ribs) and in the diaphysis of long bones (femur and humerus). Most common presentation: multiple lytic 'punched out' lesions.
Multiple myeloma does not show any uptake on bone scan.

4 main forms:

Four main patterns are recognised :

1. disseminated form : multiple defined lesions predominantly affecting the axial skeleton
2. disseminated form : diffuse skeletal osteopaenia
3. solitary plasmacytoma : single large / expansile lesion most commonly in a vertebral body or in the pelvis
4. osteosclerosing myeloma

Radiographic features

Disseminated multiple myeloma has two common radiological appearances

1- numerous, well circumscribed lytic bone lesions : more commonpunched out lucencies e.g. pepperpot skull endosteal scalloping

2- generalized osteopaenia : less common often associated with vertebral compression fractures / vertebra plana

Some bones are preferentially involved, with a typical distribution being: vertebrae > ribs > skull > shoulder > pelvis > long bones

Plain film

A skeletal survey is essential in not only the diagnosis of multiple myeloma, but also in assessing response, and pre-empting potential complications (e.g. pathological fracture).

A typical skeletal survey consists of the following films: lateral skull, frontal chest film, cervico-thoraco-lumbar spine, shoulders, pelvis, femurs.

The vast majority of myelomatous lesions are lytic ( ~ 3% being sclerotic)

CT

CT does not have a great role in the diagnosis of disseminated multiple myeloma, however it may be useful to determine the extent of extra-osseous soft tissue component in patients with a large disease burden. It may also better asses the risk of fracture in severely affected bones.

MRI

MRI is generally more sensitive in detecting multiple lesions compared to the standard plain film skeletal survey. Infiltration and replacement of bone marrow is exquisitely visualised, and newer scanners are able to perform whole body scans for this purpose.

Nuclear medicine

Bone scintigraphy appearance of patients with disseminated multiple myeloma is variable due to the potential lack of osteoblasitc activity. Larger lesions may be hot or cold. Bone scans may also be normal. Therefore bone scans usually do not contribute significant information in the work-up of patients with suspected or established disseminated multiple myeloma, as the sensitivity of detecting lesions is less than that of a plain film skeletal survey.

PET-CT has a growing role to play in the management of this disease, as it is effective in identifying the distribution of disease. Uptake of the F18-FDG molecule by the myeloma lesions corresponds to areas of bone lysis seen on CT.

Links:

http://www.radiologyassistant.nl/en/4bc6176e56228#a4bc8b5a27f351

http://radiopaedia.org/articles/multiple-myeloma-1

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Giant cell bone tumor in young female patient destroying the epihysis and parts of the metaphysis.

X-Ray Appearance and Advanced Imaging Findings:

Radiologic findings demonstrate the lesion is most often eccentrically placed to the long axis of the bone. The center is most radiolucent with increasing density towards the periphery. There is a well-defined in defect in the metaphysis and epiphysis, with destruction of the medullary cavity and adjacent cortex. The destruction may stop just short of the joint. Intact borders and a sharp inner margin may be associated with a better prognosis. These tumors often thin the cortex, and may expand into the soft tissues surrounding the bone,or they may expand the the bone extensively, remaining within an eggshell-thin rim of periosteal new bone.

(Radiologyassistant.nl)

• Presents as an eccentric lytic lesion with a geographic pattern of bone destruction, but can also have a more aggressive appearance with ill-defined borders.
• By far most giant cell tumors are seen around the knee. GCT is located in the epiphysis with or without extension to metaphysis and frequently abuts the articular surface.
• Most common bone tumor in adults aged 25 - 40 y.
• Differential diagnosis:
  • ABC may have the same radiographic features but is found in a younger age group.
  • Chondroblastoma is also located in the epiphysis, but is seen exclusively in the epiphysis without extention to the metaphysis and is seen in a younger age group.
  • Metastases, especially in older patients.

Links:

http://www.bonetumor.org/tumors-bone/giant-cell-tumor

http://www.radiologyassistant.nl/en/4bc9b15f76a78#p4bc9b4d7790e7

http://radiopaedia.org/articles/giant-cell-tumour-of-the-tendon-sheath-1

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Negative exam showing an empty, free neuronal foramen


Positive exam, showing a neuronal foramen with an occluded lumen

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Sclerotic anterior longitudinal ligament:


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