Paraspinal mass in a child 507

Paraspinal mass in a child

Semha Berberoglu, M Erkin Aribal, Unser Arikan, Asuman Ince

Oncology Hospital,Mesa Koru Sitesi,Sedir Sok 2/C, 06798Ankara, TurkeyDepartment ofPediatric OncologyS BerberogluDepartment ofRadiologyME AribalA Ince

Department ofPathology, HacettepeUniversity, 06100Ankara, TurkeyU Arikan

Accepted 6 September 1995

A nine-year-old girl was admitted to our hospital with difficulty in walking in September 1993.On physical examination there was a solid mass of 10 x 10 cm in the lumbosacral region and thepatient was unable to walk or stand. Bilateral deep tendon reflexes of the lower extremities werehypoactive and muscle strength was also decreased. There was hypoesthesia at L4, L5 and S 1 onboth legs. Babinsky test was negative bilaterally. On lumbar spine radiographs there were lytic andsclerotic lesions on the corpus of the fifth lumbar vertebra and sacrum. Results of bonescintigraphy showed intense tracer accumulation at the L5 and L5-S1 level on both blood pooland delayed images.Magnetic resonance imaging (MRI) of the lumbosacral spine showed a large mass which

invaded the multifundus and both psoas muscles. The mass extended caudally to the pelvis. Bothintervertebral foramina were dilated at L4-5, L5-S1, and S1-2 levels and the right intervertebralforamen on S2-3 level (figure 1). The mass extended into the spinal canal through these foraminaand filled the spinal canal between L5 and S3 (figure 2). The mass showed high-signal intensityon T2-weighted images and isointensity with adjacent muscles on Tl-weighted images. Aftercontrast enhancement with gadolinium DTPA the mass showed enhancement almosthomogeneously (figure 3). The soft tissue component of the mass extended between L4 andS3 levels. The fifth lumbar and the first two sacral vertebrae were of low signal intensity on Ti-weighted and of high signal intensity on T2-weighted images. Both L5 and S2 vertebral bodiesshowed inhomogeneous contrast enhancement but Si vertebra showed only a few enhancedregions (figure 3). Left L5 hemilaminectomy, left laminotomy and biopsy from the epidural masswere performed.

Questions

1 What is the diagnosis?2 What are the treatment options?

Figure 1 TI-weighted right paramediansagittal MRI. The intervertebral foraminaare dilated and filled with mass on L4-5 andL5-S1 levels (arrows). Note the intermediatesignal intensity (SI) of the mass and lower SIof the L5 vertebra

Figure 2 Median T2-weighted sagittalMRI. The hyperintense mass fills the spinalcanal between IA-S3 levels (arrowheads). L5,S1 and S2 vertebral bodies show high SI

Figure 3 Contrast-enhanced Ti-weightedmedian sagittal MRI. The mass shows con-trast enhancement (arrows). L5 and S2vertebral bodies are also enhanced

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508 Berberoglu, Anbal, Ankan, Ince

Mesenchymalchondro-sarcoma: sitesof involvement

* femur 18%* ribs 18%* jaw 16%* spine 8%* pelvis 8%

Box 1

Figure 4 Mesenchy-mal chondrosarcomarich with spindle tu-mour cells. (H&E, ori-ginal x 230)

Figure 5 Photomicro-graph showing thechondroid areas in themesenchymal chondro-sarcoma. (H&E, origi-nal x 460)

Answers

QUESTION 1Pathological examination revealed mesenchy-mal chondrosarcoma characterised by undif-ferentiated mesenchymal cells and islands ofmalignant cartilage differentiation (figures 4and 5).

QUESTION 2Surgery is the major method of treating thedisease. Chemotherapy and radiotherapy maybe used as additional therapeutic modalities.

Discussion

Chondrosarcoma is primarily a tumour ofadulthood. Its occurence in children is un-common.' Mesenchymal chondrosarcoma is arare variant of chondrosarcoma which actsbiologically and, in its response to treatment,in a completely different way from the morecommon differentiated forms.2 It is about 70times less common than the intramedullaryosteosarcoma, and five times less commonthan fibro- or osteosarcomatous transforma-tion of chondrosarcoma.'

CLINICAL FEATURESAbout 80% of patients are younger than age 40years. There is no gender predilection. Ap-proximately 0.5% of biopsy-analysed primarybone tumours are mesenchymal chondrosar-comas. It is about one tenth as common asconventional chondrosarcomas. Lesions rangefrom 1 to 40 cm (average about 10 cm) inlongest dimension. The most common sites ofinvolvement are shown in box 1. The longbones are affected in only 28% of cases. Most

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lesions begin as solitary bone lesions, althoughlesions of soft tissue and multifocal osseousorigin have been reported.3'4 About 66% oflesions originate from bones or meninges andthe remaining from the soft tissues.3

SIGNS AND SYMPTOMSPain (80% of patients) and/or swelling (70%)are the dominating clinical stigmata. Pain maybe of a month to five or more years duration.More than 50% of patients have experiencedpain for less than six months when firstevaluated. If the tumour is near a joint,instability, limitation of motion, stiffness, andeffusion are possible. When located in themeninges, the symptoms are headache (intra-cranial), cranial nerve palsies and visual symp-toms (base of skull), and pain, stiffness,sensory and motor deficits, and subarachnoidhaemorrhage (spinal).

RADIOLOGIC FEATURESThe radiologic manifestations (box 2) are notdiagnostic. Definitive diagnosis depends onbiopsy. In about two-thirds of cases, radio-graphs of lesions exhibit stippled densities,which are highly suggestive of the presence ofcartilage. The radiologic appearance usuallyprompts a diagnosis of chondrosarcoma orosteosarcoma, as mesenchymal chondrosarco-ma has no pathognomonic radiologic features,and is less common than the former tumours.

DISEASE COURSEThis tumour is fully malignant, and carries aless favourable prognosis than conventionalchondrosarcomas. Fewer than 30% of patientstreated by surgical methods are alive after 10years. Patients must undergo radical surgical

Mesenchymal chondrosarcoma:radiologic appearance

* intraosseous primary lesions: most oftenassociated with large, lobulated soft tissuemass; remaining lesions are predominantly lytic

* periosteal lesions: most often demonstrate alarge, juxtacortical, lobulated soft tissue masswith prominent coarse, stippled or short lineardensities; remaining lesions are predominantlylytic

Box 2

Mesenchymal chondrosarcoma:histologic findings

Constant findings* undifferentiated mesenchymal cells* multifocal differentiation into malignant

cartilage

Variable histologic findings* haemangiopericytoma-like features* herringbone spindle cell pattern* 'pushing' versus permeative borders* necrosis and haemorrhage* osseous metaplasia

Box 3

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Paraspinal mass in a child 509

Mesenchymal chondrosarcoma:differential diagnosis

* chondrosarcoma with fibrosarcomatoustransformation

* osteosarcoma* fibrosarcoma* chondroblastoma* chondromyxoid fibroma* Ewing's sarcoma

Box 4

_

Figure 6 Axial CTimage at L5 level. Theparavertebral mass, andthe intraspinal compo-nent show speckled cal-cification. The right L5-S 1 intervertebral fora-men is enlarged by themass

procedures to reduce the rather high incidenceof local recurrence. Metastases to the lungsand other bones (predominantly spine, skulland ribs) may be seen as late as 10 years aftersurgery. Metastases to lymph nodes rarelyoccur.3 Some variants of the tumour respondfavourably to chemotherapeutic agents.

In our patient, radiotherapy was adminis-tered to L3-S2 region to a 11 x 8 cm area, withCo-60 at a dose of 4680 cGy in October 1993.Four courses of chemotherapy with cisplati-num (120 mg/m') and doxorubicin (30 mg/m'daily for two days every three weeks) wereadministered.

In January 1994, on control examination,plain abdominal X-ray showed paraspinalheavy calcification. On computed tomograph(CT) examination the mass was enlarged intothe abdomen and pelvis and showed heavycalcification with a speckled pattern (figure 6).The intraspinal component ofthe mass showedthe same pattern of calcification. Lytic lesions

were present in the fifth lumbar and first twosacral vertebrae. On thoracic CT, 1 x 2 cmmass was observed at the right paracardiacregion. She died of progressive disease inMarch 1994.

In our patient MRI clearly showed theextension of the tumour with its multiplanarimaging capability and good soft tissue resolu-tion. Plain abdominal X-rays and especiallyCT showed heavy calcifications of the tumour.MRI failed to show these calcifications, butafter contrast enhancement, nonenhanced ir-regular foci, which were thought to belong tothese calcifications, were present. MRI wasbetter than CT in showing the three-dimen-sional localisation of the mass because of itsmultiplanar imaging capability. The intraspinalcomponent of the tumour could be betterevaluated with MRI, especially because of itssagittal images. MRI was therefore a betterimaging modality for evaluation of the tumourextension but failed to show the calcificationpattern that can be a clue for differentialdiagnosis.

Although surgery is the major method oftreating the disease, radical surgery could notbe performed because of the vertebral localisa-tion of the tumour. In the literature it wasreported that unresectable tumours respondedto irradiation and chemotherapy. In ourpatient, however, local and systemic metastaseswere detected during chemotherapy and radio-therapy was also ineffective. Poor prognosticfactors, such as pain and the central location ofthe tumour might be the cause of this rapidprogression, as discussed in the publisheddata.3

In conclusion, although rare in children,mesenchymal chondrosarcoma may be curedwith radical surgery, chemotherapy and radio-therapy if the disease has not progressed.Radiologic examination, especially with MRI,is useful in showing the tumour extension.

Final diagnosis

Paraspinal mesenchymal chondrosarcoma.

Keywords: MRI, paraspinal mesenchymal chondro-sarcoma

1 Young CL, Sim FH, Unni KK, McLead RA. Chondro-sarcoma of bone in children. Cancer 1990; 66: 1641-48.

2 Harwood AR, Krajbich JI, Fornasier VL. Mesenchymalchondrosarcoma. Clin Orthopaed Rel Res 1981; 158: 144 - 8.

3 Mirra JM. Mesenchymal chondrosarcoma. In: Mirra JM,Picci P, Gold Rh, eds. Bone tumors. Philadelphia: Lea &Febiger. 1989; pp 577-88.

4 Salvador AH, Beabout JW, Dahlin DC. Mesenchymalchondrosarcoma. Observations on 30 new cases. Cancer1971; 28: 605.

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