CHONDROSARCOMA OF THE OCCIPITAL BONE A case presentation

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CHONDROSARCOMA OF THE OCCIPITAL BONEA case
presentation

• By Dr G.K.Swethadri , Dr. C.K.Ballal.

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BRIEF HISTORY

• 35 yr old male , Agriculturist by profession
• c/o headache on off since 2 years
• pain in the neck since 1 ½ months
• Family history nothing contributory
• O/E no bony exostosis

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INVESTIGATIONS

• 1. CT SCAN ( 2 .1 .07 )
• Skull based mass lesion in posterior fossa with
  erosion of anterior margin of Foramen Magnum ,
  occipital condyle clivus with intracranial
  extension
• DDs offered Paraganglioma
• Metastasis

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• 2. HRCT of Temporal bone
• Suspected case of Glomus Jugulare
• Expansion of right jugular foramen with erosion
  of right petrous temporal bone , basiocciput
  clivus
• Soft tissue attenuation lesion

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• 3. FOUR VESSEL ANGIOGRAM
• No tumour blush
• Normal study of intra extracranial carotid
  vertebral arteries

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• 4. MRI
• Moderate spondylotic changes at lower cervical
  levels
• C4 C5 diffuse posterior bulge
• C5 C6 C6 C7 diffuse bulge with posterior (
  central ) protrusion
• No cord compression or foraminal narrowing
• Bones normal

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• Mixed density lesion ( 2.6 x 2.7 x 2 cm )
• Cystic foci seen
• Involves right occipital condyle , adjacent bone
  soft tissue areas
• To rule out inflammatory / soft tissue lesion
• Advised MRI with contrast

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INTRAOPERATIVE FINDINGS

• Approach Rt retromastoid skull based approach
• Lesion was close to the occipital condyle
• Firm , moderately vascular , not attached to dura

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GROSS FINDINGS 418 / 07

• Multiple pale brown to haemorrhagic tissue bits
  amounting to 1 ml

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Steps of diagnosis

• Specimen received with brief history with a
  request for squash diagnosis
• Squash smears were made and found the specimen
  was not easily squashable.
• However a few cells seen betrayed the possibility
  of a malignant tumour.

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Squash preparationLoose pleomorphic cells
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Frozen Section

• The tissue bits were tough to squash therefore a
  frozen section was made
• Showed cohesive sheets of oval to spindle cells.
• Mitosis were seen.
• It suggested soft tissue tumour

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• The chondroid nature was not appreciated at this
  stage.
• Radiological absence of calcification also did
  not alert to chondroid tumour.

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Sheets of round to spindle cells
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Paraffin sections

• The regular paraffin section revealed chondroid
  areas in a malignant soft tissue tumour.
• The close study of chondroid areas revealed a low
  grade chondrosarcoma.
• There was abrupt transition from chondroid to
  soft tissue areas suggesting Dedifferentiated
  CHS.

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Cartilagenous lobules spindle cell areas
infiltration to bony trabeculae with destructon
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Chondrosarcomatous areas
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Pleomorphic cells in chondroid matrix
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CHS
Bone
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Distinct chondroid and spindle areas
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DIAGNOSIS

• CHONDROSARCOMA
• GRADE 2
• (diagnosis made on a small sample)

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DISCUSSION

• CHS is uncommon in the skull.
• mesenchymal CHS can rarely occur in the meninges
• 2 of CHS can occur in the skull.

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Chondrosarcoma (CHS)

• Definition CHS is a malignant tumour with pure
  hyaline cartilage differentiation.
• Classification
• Primary chondrosarcoma
• Periosteal CHS
• Secondary CHS
• Secondary CHS in Ollier disease Maffucci syn
• Dediffereniated CHS
• Mesenchymal CHS
• Clear cell CHS

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Primary CHS

• Primary CHS is 3rd most common primary malignant
  tumour of bone.
• Usually presents gt 50 yrs
• Common sites Pelvis,femur,humerus,ribs
• They are radiolucent with punctate opacities,
  cortical thickening and erosion.

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• Gross Blue gray translucent , lobular
  growth,myxoid,mucoid,chalky areas, erosion of
  bone are seen.
• Micro Lobules of cartilage separated by bands of
  connective tissue , hypercellularity,
  hyperchomatism and binuclearity and invasion of
  cortex and trabecular bone
• Note Lobules of cartilage are predominant

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Dedifferentiated CHS

• Contains two clearly defined components i .e. a
  well differentiated cartilage tumour (chondroma
  or low grade CHS ) and a juxtaposed high grade
  soft tissue sarcoma and there is histologically
  abrupt transition between the two.
• Epidemiology constitute 10 of all reported CHS
  
• Age group 50-60 yrs with a range of 29-85.
• Sites Pelvis, humerus and femur.

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• Symptoms.
• pain,swelling,paraesthesia,path ,illdefined
  lytic intraosseous lesion with cortical
  perforation,extraosseous extension.preexisting
  chondroid lesion may be separately seen.
• Gross. Both bluish cartilagenous component and
  fleshy noncartilagenous component are evident.

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• HISTOPATHOLOGY
• Cartilagenous component is usually low grade
  chondrosarcoma.
• Malignant component could be
• MFH
• FIBROSARCOMA
• OSTEOSARCOMA
• RMS

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• Genetic studies have shown multiple mutations
  responsible for the varied multilineage
  dedifferentiation
• Prognosis aggressive neoplasm,poor prognosis.
• 90 patients are dead of distant metastasis by 2
  years.

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Mesenchymal CHS

• Has cartilagenous areas and cells resembling
  Ewings sarcoma.
• Ultrastructurally cartilage cell and round cells
  resemle mesenchymal cells.

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Clear cell CHS

• Has bland clear cells in addition to hyaline
  cartilage

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Prognosis

• Grade 1. 5 yr survival 78
• Grade 2. 53
• Grade 3. 28

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• Usually CHS are of low grade in the base of the
  skull they have distinct lobulations.
• However distinct high grade spindle areas in
  addition to CHS foci with absence of
  calcification and lytic lesions place the tumour
  in a much higher grade with poorer prognosis

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• Diagnosis subsequently modified as
• Dedifferentiated CHS

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• This variant is rare in skull though poorly
  differentiated CHS can rarely occur in meninges.
• It is suspected if cartilage is detected AS IN
  OUR CASE also.
• S-100 protein is positive as a nonspecific
  marker.

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Reference to a few series

• 5 patients with grade 1 2 chondrosarcoma 1
  case of mesenchymal chondrosarcoma were treated
  between 1967 1991
• Sex ratio was equal
• Symptoms were diplopia , decreased visual acuity
  cranial nerve involvement
• It was rare to find chondrosarcoma without
  attachment to base as base is embryologically
  derived endochondrally

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• In this location chondrosarcoma developed
  from
• Metaplastic chondrocytes or
• Clones of normal cells or
• Heterotropic cartilagenous cells or
• Pluripotential mesenchymal cells

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Differential diagnosis of parasellar /
retrosellar mass

• NPC
• Metastasis
• Schwannoma
• Chordoma
• Meningioma
• Glomus jugulare etc

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• Differential diagnosis chordoma , chondrosarcoma
  mengioma is difficult
• The former 2 are osteolytic.

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INCIDENCE OF BASAL TUMORS

• Saunders et al 1985 19 cases
• 10 chordoma , 5 CHS , 4 meningioma
• Kveiton et al 1986 5 cases
• All CHS
• Austin seymour et al 1989 68 cases
• 36 NCC , 4 chordomas , 28 CHS
• Kondziolka et al 1991 6 cases
• 2 CHS , 4 chordomas

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Maffucci syndrome Ollier disease

• Chondromas are part of the above syndrome
• However there only 6 cases of CHS of the skull
  reported in these cases.

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Take home message..

• Though CHS is rare it should be kept in mind
  whenever a skull based malignant tumour is
  encountered
• Whenever chondromas are encountered in the skull
  , tranformation to CHS should be investigated

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REFERENCES

• Tadashi Morimoto ,MD Tomio Sasaki , MD
  Kintoko Takakuru ,MD Tsuyoshi Ishada ,MD
  ,Chondrosarcoma of skull base , Report of 6 cases
  ,Skull base surgery,Vol 2,Number 4,1992, p177
• Pathology and genetics.tumours of the soft
  tissue and bone.Edited by Christopher
  D.M.Fletcher,K.Krishnan Unni,M Fredrik
  Mertens.IARC press LYON 2002.p 247.
• Joseph M.Mirrah,Bone tumours.J.B.Lippincot
  company.

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THANK U