Tumors arising from nerve tissue & fat tissue in bones

NEUROFIBROMAS NEUROFIBROMATOSIS

Benign peripheral nerve sheath tumours. Peak age......... 20-30yrs No sex predilection

3 types Localized Diffuse Plexiform

Most common, 90% Solitary, not associated with NF 1 Affects superficial cutaneous nerves Slow growing <5cm in size at presentation

Children, young adults. Solitary, not associated with NF 1. Located within s/c tissue of head & neck. Cause plaque like elevation of skin with

thickening of entire sub cutis.

Diffuse involvement of long nerve segment and its branches, extending beyond epineurium into surrounding tissue

Pathognomic of NF 1 Early childhood Malignant transformation

Neurofibroma arising in the obturator ring has caused considerable pressure erosion of both right pubic rami, particularly the superior one. The margins of the pressure defect are sharply defined.

Two large ovoid neurofibromas (arrows) are shown as filling defects within the thecal sac at the L4/5 level

Majority solitary Neurofibromatosis Multiple neurofibromas...diagnostic of NF 1

CT Well defined, hypodense mass Little or no contrast enhancement

Multiple paravertebral neurofibromas which are hypodense, well defined and enlarge neural foramina

ct shows contrast enhancing soft tissue mass parietal and occipital on the left side. Bone window images show destruction and deformity of the occipital bone due to biopsy proven neurofibroma

MRI T1: hypointense T2: hyperintense

▪ Target sign

T1 post contrast: heterogeneous enhancementPLEXIFORM: large lobulated and conglumerated

masses extending along nerves and its branches

T1w axial through cervical spine shows a low signal intensity mass extruding through right foraminal canal at c5-c6 level, eroding the vertebral body.

T2w hyperintense neurofibroma

Multisystem neurocutaneous disorder Most common phakomatosis Most common inherited CNS disorder,

autosomal dominated disorder 1:3000, M=F 50% inherited, 50% spontaneous

>6 cafe au lait spots Neurofibromas

2 cutaneous or 2 subcutaeous or 2 nodular or 1 plexiform

Optic nerve glioma Distinctive osseous lesions Sphenoid wing dysplasia Two or more iris hamartomas (Lisch nodules) Axillary or inguinal freckling Primary relative with NF1

Cutaneous neurofibromata

Subcutaneous neurofibroma

Optic nerve glioma Soft tissue density lobulated lesion encasing the left optic nerve

Plain radiograph of forearm of 15 yr old boy shows hypoplasia and deformity of radius and ulna. intramedullary sclerotic streaks in radius and periosteal deformity

sphenoid wing dysplasia ,t2

NF1 gene locus is on 17q11.2 and the gene product is neurofibromin, act as a tumour suppressor.

Tumour is primarily a hamartomatus disorder involving ectoderm and mesoderm

Kyphoscoliosis Posterior vertebral scalloping Posterior hypoplastic elements Enlarged neural foramina Ribbon rib deformity, rib notching, dysplasia Dural ectasia Tibial pseudoarthrosis, bony dysplasia affecting

tibia Severe bowing Multiple NOF Limb hemihypertrophy

Kyphoscoliosis Combination of outward curvature and lateral curvature

Posterior vertebra scalloping

Ribbon ribs

Sagittal T1WI unenhanced scan in a28 yr old women shows dural ectasia and a large lobulated anterior sacral meningocele.

Pseudarthroses of the tibia and fibula shown in an infant. Bowing of bone and absence of any evidence of bone repair are typical.

Axial sonogram through right iliac fossa in 28 YR OLD man with nf1 shows a dumbbell shape neurofibroma

solitary neurofibroma displacing the femoral vessels there is clear mesenchymal dysplasia, with extensive abnormalities of subcutaneous tissue and hemihypertrophy.

CNS: dysplasias,hamartomas,neoplasms OCCULAR: buphthalmos GI: carcinoid tumor ENDOCRINE: pheocromocytoma GU: wilms tumor PULMONARY: interstitial fibrosis

Rare autosomal dominant neurocutaneous disorder

Not associated with neurofibromas

MISME Multiple inherited schwannomas Meningioma Ependymoma

LIPOMA INTRAOSSEOUS PARAOSTEAL

LIPOSARCOMA

Rare bone lesion Most common lipogenic tumor in bone 4-5th decade of life Slight male predilection

PAIN Anywhere in the skeleton Long bones..........metaphysis, medullary

cavity

o Lower limb 71%o Calcaneum 32%o Femur 20%o Tibia 13%o Fibula 6%

o Upper limb 7%o Skull, mandible 7%o Spine and pelvis 12%o Ribs 2.5%

PLAIN FILM Osteolytic Well defined margins

intraosseous lipoma within the calcaneum

3 CATEGORIES• TYPE 1: sharply delineated, viable lipomas,

homogenous fat content

Homogenous hyperintense fat signal on T1 and T2WI, suppressed by STIR

• TYPE 2: predominantly fatty lesions with central necrosis, calcifications or ossifications

Hypointense inclusions on T1WI which may appear hyperintense on STIR(granulation tissue) or hypointese( calcifications or ossifications)

• TYPE 3: heterogeneous, fat containing lesions with necrosis, cystic transformation, wall sclerosis, extensive calcifications or ossifications.

Fluid equivalent cavities, signal void bony septae, surrounded by signal void rim of sclerotic bone.

Intraosseous lipoma with cystic transformation

CALCANEAL CYST

Rare benign tumour associated with periosteum

0.3% of lipomas

Slow growing, painless, immobile mass, not fixed to skin

Nerve compression with forearm lesions Firmly adherent to underlying cortex Femur, proximal radius

PLAIN FILM Bowing of bone or cortical erosion

Parosteal lipoma .A discrete tumour arises from the interosseous membrane of the forearm

CT Septations Prominent osseous protuberance Mild enhancement in fibrous tissue

MRI Juxtacortical heterogeneous lobulated sepated

mass with signal intensity similar to subcutaneous fat.

Adjacent muscle atrophy is better seen on T2

Axial t1wi showing a high signal intensity mass arising from surface of humerus and bulging from beneath the deltoid muscle with low signal exophytic mass arising from humerus

BONE SCINTIGRAPHY Increased uptake

PARAOSTEAL LIPOSRACOMA Soft tissue fails to contain fatty lucencies

INTRAOSSEOUS LIPOSARCOMA Ill-defined lytic lesion Femur, tibia Vascular Rapid extension into soft tissue Early pulmonary metastasis