Introduction Among the various entities which cause spinal neural foraminal widening, neurofibromas are the most com- mon ones [1, 2]. Rare lesions can also cause spinal neu- ral foraminal widening. Computed tomography and/or MR imaging are the modalities of choice for studying the spinal foraminal widening. The present pictorial re- view describes six such rare lesions, namely a lateral thoracic meningocele, a malignant fibrous histiocytoma, a tuberculous abscess, an osteoblastoma, a chondrosar- coma and a pancoast tumour of the lung. Histological examination was done in all but one case to establish the diagnosis. Clinical aspects and radiological findings of rare lesions causing spinal neural foraminal widening Lateral thoracic meningocele Lateral thoracic meningocele is characterized by cere- brospinal fluid (CSF)-filled protrusions of dura and arachnoid through one or more enlarged neural forami- na into the paraspinal, extrapleural or retroperitoneal tissues [3]. The lesion is seen clearly on MR images as a rounded or oval mass with homogeneous signal intensi- ty typical of cerebrospinal fluid (low on T1- and high on T2-weighted images) which communicates via a neu- ral foramen with the subarachnoid space (Fig. 1). It can be unilateral or bilateral and is commonly associated with scoliosis. Males and females are affected equally. The majority of lateral thoracic meningoceles occur on the right side in the upper thoracic region, typically at T5–T6. Lateral meningoceles are most common in pa- tients with mesenchymal disorders such as neurofibro- matosis, Marfan’s and Ehler-Danlos syndromes. Neu- rofibromatosis is present in 85 % of cases [3]. The me- ningoceles are usually asymptomatic but may cause pain (23 %) and neurological deficits (19 %). Malignant fibrous histiocytoma Malignant fibrous histiocytomas (MFH) are distinctive neoplasms because they are composed of a mixture of cells resembling fibroblasts, myofibroblasts, histiocytes, primitive mesenchymal cells and cells having intermedi- ate or mixed features (i. e. fibrohistiocytoid cells). Addi- tional features include rich vascularization and varying numbers of giant cells and lipid-laden xanthomatous cells [4]. Malignant fibrous histiocytoma occurs mainly in soft tissues, but also occasionally in bone [5]. It is be- lieved that these tumours arise from primitive mesen- chymal cells capable of multidirectional differentiation [4]. Although complete excision in the axial skeleton re- mains a near impossibility, it is believed that adequate Eur. Radiol. 10, 144–148 (2000) Ó Springer-Verlag 2000 Neuroradiology European Radiology Pictorial review Unusual causes of spinal foraminal widening A. H. Zibis, A. Markonis, A. H. Karantanas Department of CT and MRI, Larissa General Hospital, 1 Tsakalof Street, GR-412 21 Larissa, Greece Received: 23 November 1998; Revised: 4 March 1999; Accepted: 20 April 1999 Abstract. Spinal neural foraminal widening is usually caused by benign lesions, most commonly neurofi- bromas. Rare lesions can also cause spinal neural fo- raminal widening. Computed tomography and/or MRI are the modalities of choice for studying the spi- nal foraminal widening. The present pictorial review describes six rare lesions, namely a lateral thoracic meningocele, a malignant fibrous histiocytoma, a tu- berculous abscess, an osteoblastoma, a chondrosarco- ma and a malignant tumour of the lung which caused spinal neural foraminal widening. Key words: Spinal neural foramina widening – CT – MRI Correspondence to: A. H. Karantanas
Transcript
Introduction
Among the various entities which cause spinal neuralforaminal widening, neurofibromas are the most com-mon ones [1, 2]. Rare lesions can also cause spinal neu-ral foraminal widening. Computed tomography and/orMR imaging are the modalities of choice for studyingthe spinal foraminal widening. The present pictorial re-view describes six such rare lesions, namely a lateralthoracic meningocele, a malignant fibrous histiocytoma,a tuberculous abscess, an osteoblastoma, a chondrosar-coma and a pancoast tumour of the lung. Histologicalexamination was done in all but one case to establishthe diagnosis.
Clinical aspects and radiological findings of rare lesionscausing spinal neural foraminal widening
Lateral thoracic meningocele
Lateral thoracic meningocele is characterized by cere-brospinal fluid (CSF)-filled protrusions of dura andarachnoid through one or more enlarged neural forami-na into the paraspinal, extrapleural or retroperitonealtissues [3]. The lesion is seen clearly on MR images as arounded or oval mass with homogeneous signal intensi-ty typical of cerebrospinal fluid (low on T1- and highon T2-weighted images) which communicates via a neu-ral foramen with the subarachnoid space (Fig.1). It canbe unilateral or bilateral and is commonly associatedwith scoliosis. Males and females are affected equally.The majority of lateral thoracic meningoceles occur onthe right side in the upper thoracic region, typically atT5±T6. Lateral meningoceles are most common in pa-tients with mesenchymal disorders such as neurofibro-matosis, Marfan's and Ehler-Danlos syndromes. Neu-rofibromatosis is present in 85% of cases [3]. The me-ningoceles are usually asymptomatic but may causepain (23 %) and neurological deficits (19 %).
Malignant fibrous histiocytoma
Malignant fibrous histiocytomas (MFH) are distinctiveneoplasms because they are composed of a mixture ofcells resembling fibroblasts, myofibroblasts, histiocytes,primitive mesenchymal cells and cells having intermedi-ate or mixed features (i. e. fibrohistiocytoid cells). Addi-tional features include rich vascularization and varyingnumbers of giant cells and lipid-laden xanthomatouscells [4]. Malignant fibrous histiocytoma occurs mainlyin soft tissues, but also occasionally in bone [5]. It is be-lieved that these tumours arise from primitive mesen-chymal cells capable of multidirectional differentiation[4]. Although complete excision in the axial skeleton re-mains a near impossibility, it is believed that adequate
Eur. Radiol. 10, 144±148 (2000) Ó Springer-Verlag 2000
Neuroradiology EuropeanRadiology
Pictorial review
Unusual causes of spinal foraminal wideningA. H. Zibis, A. Markonis, A. H. Karantanas
Department of CT and MRI, Larissa General Hospital, 1 Tsakalof Street, GR-412 21 Larissa, Greece
Received: 23 November 1998; Revised: 4 March 1999; Accepted: 20 April 1999
Abstract. Spinal neural foraminal widening is usuallycaused by benign lesions, most commonly neurofi-bromas. Rare lesions can also cause spinal neural fo-raminal widening. Computed tomography and/orMRI are the modalities of choice for studying the spi-nal foraminal widening. The present pictorial reviewdescribes six rare lesions, namely a lateral thoracicmeningocele, a malignant fibrous histiocytoma, a tu-berculous abscess, an osteoblastoma, a chondrosarco-ma and a malignant tumour of the lung which causedspinal neural foraminal widening.
anterior decompression combined with postoperativeradiation therapy is the best treatment option [5]. Thepatient in our study (Fig. 2) received radiation therapyand chemotherapy and 12 months later remains stablewith no clinical or radiological indications of recurrence.
Spinal tuberculosis
The spine is the most commonly involved part of theskeleton by tuberculosis accounting for 25±60 % ofcases [6]. It is usually the result of haematogenousspread but can also occur as direct extension from thelungs or subarachnoid space in cases of tuberculousmeningitis. The intervertebral space remains relativelyintact longer in tuberculosis than in pyogenic infections.Plain radiographs are very useful to demonstrate boneand joint involvement which may be similar to pyogenicinfections. Computed tomography is a very sensitiveprocedure for demonstrating spinal and extraspinal tu-berculosis. However, the findings are not specific be-cause they are similar to those of other osteomyelyticprocesses. Although intraspinal involvement may bedemonstrated by CT, additional myelography or MRImay be necessary to reveal intraspinal involvement.Epidural extension may cause compression of the spinalcord or of the cauda equina [7]. The posterior arch ofthe vertebra is reported to be involved in 2±10 % ofcases of spinal tuberculosis [7]. However, involvementof the posterior arch with sparing of the vertebral bodyhas been seen in less than 2 % of spinal tuberculosiscases, with the pedicle being most often affected [8].The case described in our study (Fig.3), in which foram-inal widening is caused, is the first such case, to ourknowledge, reported in the literature.
Osteoblastoma
Osteoblastoma is a benign uncommon (1 % of all prima-ry bone tumours) bone-forming tumour characterizedby the synthesis of osteoid matrix that may become min-eralized [9]. Almost 90% of these lesions are encoun-tered in persons between the first and the third decadesof life, and spinal location accounts for 44% of cases. Itis a painful lesion and the symptoms are a result of neu-rological compression. Radiographically it is character-ized by a lytic lesion, usually more than 1.5 cm in size,with sclerotic border affecting primarily lamina andpedicles. As complete surgical removal of these tumoursis the treatment of choice, the radiological evaluationshould demonstrate the bony as well as soft tissue por-tions of the tumour (Fig. 4).
Chondrosarcoma
Chondrosarcoma is a skeletal malignancy producing hy-aline cartilage and 25% of them arise in the spine andribs [10]. Radiologically osteosarcoma is characterizedby the location, the shape (cauliflower-like) and calcifi-cation pattern of the intraspinal component of the lesion(seen clearly on CT images), associated with large para-spinal soft tissue mass, which shows enhancement afteradministration of paramagnetic contrast on MR images.Nevertheless, radiological and histological findings maybe indistinguishable or only subtly different from thoseof benign lesions, leading all too often to underdiagnosisand inadequate treatment. Chondrosarcoma readily im-plants into the soft tissues, with such recurrences ad-versely affecting survival. Thus, resection must be radi-cal, including a wide margin of normal tissue. Therefore,MRI is the method of choice because it can provide theappropriate preoperative information for a successfulresection. In our case (Fig. 5) the possibility of multiplehereditary exostosis was excluded by radiological inves-tigation. To our knowledge, spinal neural foramen wid-ening caused by chondrosarcoma is rare, with only onecase having been reported previously [11].
A. H.Zibis et al.: Unusual causes of spinal foraminal widening 145
a b
Fig.1a, b. A 65-year-old male with haemoptysis and a mass sug-gestive of lateral thoracic meningocele. T2-weighted MR imagesshow a high-signal-intensity lesion which is in continuity with intra-spinal cerebrospinal fluid and causes widening of the second andthird neural foramen. There is also widening of the spinal canalalong with minor scalloping of the posterior wall of the vertebralbody. The haemoptysis happened to be unrelated to the spinal ab-normality in this patient with no neurofibromatosis
Lung tumour
The superior sulcus tumour described by Pancoast pre-sents a distinct diagnostic problem often presentingwith pleural pain and brachial plexopathy with or with-out Horner syndrome [12]. One third of patients showbone destruction on initial evaluation, but pleural inva-sion and spinal foramina widening is a very rare sign.Magnetic resonance imaging is the method of choicefor evaluation of apical chest wall infiltration [13]. Theradiological diagnosis is straightforward as in our case(Fig. 6), since the soft tissue mass at the lung apex sug-gests the origin of the lesion.
Discussion
Widening of the intervertebral foramen is a common ra-diological sign, suggesting not always a benign lesion.According to the experience described herein, imagingwith CT and/or MRI was essential for delineation ofthe lesions and helpful in narrowing the differential di-
A. H. Zibis et al.: Unusual causes of spinal foraminal widening146
Fig.3. A 63-year-old male, bedridden with pain at thoracolumbarregion and a histopathological diagnosis of tuberculous abscess af-ter surgical decompression. A CT myelography shows an extradur-al soft tissue mass which causes bilateral neural foramen wideningalong with anterior displacement of the thecal sac. The mass is ex-tended beneath the right hemidiaphragm and in the right paraspi-nal muscles
a b
c
Fig.2a±c. A 46-year-old female with lowback pain radiating at both lumbar regionsfor the past 30 months and a histopathologi-cal diagnosis of malignant fibrous histiocy-toma of the spine. a Sagittal T1-weightedMR image shows a low-signal-intensity le-sion at T10±T11 vertebrae which compressesthe lower spinal cord. The vertebral bodiesT10 and T11 are also infiltrated. b SagittalT2-weighted MR image shows the low-sig-nal-intensity lesion at T10±T11 levels andthe infiltrated T10 and T11 vertebral bodies.c Axial MR images (T2-weighted on the left,T1-weighted in the middle and T1-weightedafter contrast administration on the right)show the bilateral widening of neural fora-men. The lesion also caused significant cen-tral spinal stenosis with compression of thelower spinal cord
A. H.Zibis et al.: Unusual causes of spinal foraminal widening 147
4a 4b
5a 5b
5c 6
Fig.4a, b. A 16-year-old male with thoracic back pain and a histo-pathological diagnosis of osteoblastoma. a A CT scan shows a cal-cified lesion (arrowheads) which causes cord compression and ero-sive widening of the right T11±T12 neural foramen producing adumbbell mass. b Axial T2-weighted gradient-echo MR image.The mass displaces the cord without infiltrating it (arrows). Infil-tration of the cancellous bone of the vertebral body is also evident
Fig.5a±c. A 41-year-old female with pain at the right shoulderarea lasting for the past 6 weeks, right C7 root paresis, and a histo-pathological diagnosis of high-grade chondrosarcoma. a A CTscan shows widening of C6±C7 neural foramen (arrow) and erosionof the transverse process on the right side along with a soft tissue
mass anteriorly (arrowhead) with no obvious calcifications. b Axi-al contrast-enhanced T1-weighted MR image shows the wideningof the right neural foramen and an enhancing soft tissue masswith dumbbell configuration (arrow). The mass is displacing thethecal sac to the left. c Postoperative contrast-enhanced T1-weighted MR image shows the recurrence of the tumour
Fig.6. A 55-year-old male with lower cervical and supraclavicularpain on the left side and a histopathological diagnosis of squamouscell carcinoma. The axial contrast-enhanced T1-weighted MRI ex-amination shows a tumour at the left upper lung invading the pleu-ral surface and causing T2±T3 foraminal widening
agnosis. Correct diagnosis was suggested in all but oneof the aforementioned cases. Malignant fibrous histiocy-toma was not correctly diagnosed since this is the first,to our knowledge, described case of MFH causing spinalneural foramen widening.
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