Chondrosarcoma causing cervical neural foramen widening

Eur. Radiol. 7, 1028–1030 (1997)  Springer-Verlag 1997

European Radiology

Case report Chondrosarcoma causing cervical neural foramen widening ¨ stu¨n1, R. N. S¸ener1 N. Yu¨nten1, C. C ¸ alli1, M. Zileli2, E. E. U 1 2

Department of Radiology, Ege University Hospital, Bornova, Izmir, 35100, Turkey Department of Neurosurgery, Ege University Hospital, Bornova, Izmir, 35100, Turkey

Received 6 August 1996; Revision received 5 November 1996; Accepted 10 December 1996

Abstract. Various neoplastic, vascular, and developmental causes may lead to spinal neural foraminal widening, the most common causes of spinal dumbbell lesions being schwannomas and neurofibromas. Occasionally, some other slow-growing tumors may cause neural foraminal widening. We report an exceptional case of a low-grade spinal chondrosarcoma which apparently developed from a pre-existing osteochondroma in the neural arcus of C6. The lesion passed through the C5–C6 foramen, producing a dumbbell mass. Key words: Spinal cord compression – Spine, neoplasms – Osteochondroma – Chondrosarcoma – Computed tomography – Magnetic resonance imaging

Introduction Various tumoral, vascular, and developmental causes may lead to spinal neural foraminal widening [1–5]. The most common cause is the so-called dumbbell schwannoma or neurofibroma. Other slow-growing tumors such as chordomas, ependymomas, and meningiomas may occasionally cause neural foraminal widening [1]. We report a patient with a low-grade spinal chondrosarcoma passing through the C5–C6 foramen, a dumbbell chondrosarcoma representing an exceptional condition.

widening and calcifications at the region of the left C5– C6 neural foramen (Fig. 1). Computed tomography (CT) revealed a calcified lesion originating from the neural arcus of C6, which caused cord compression (Fig. 2 a), and erosive widening of the left C5–C6 neural foramen producing a dumbbell mass (Fig. 2 b). There was invasion and almost complete obliteration of the foramen of the left vertebral artery and vein (Fig. 2 a). There was a large paraspinal soft tissue component with calcifications (Fig. 2 b). The lesion returned heterogeneous low signal on T1-weighted magnetic resonance (MR) images (Fig. 3 a), and high signal on T2-weighted images (Fig. 3 b). In the paraspinal soft tissue mass, strong peripheral enhancement was noted on MR images obtained after administration of contrast medium (Fig. 3 c). MR angiography revealed localized narrowing of the left vertebral artery due to compression by the mass (Fig. 3 d). The location, shape (cauliflower-like), and calcification pattern of the intraspinal lesion suggested a slowgrowing tumor – an osteochondroma; however, the associated large, enhancing paraspinal soft tissue mass raised the possibility of sarcomatous degeneration of a pre-existing osteochondroma. At surgery total extirpation of C6, the mass and its soft tissue component was performed. Histopathological examination revealed a low-grade chondrosarcoma (Fig. 3). Family history and a skeletal survey of the patient did not reveal any other osteochondromatous lesion, excluding multiple hereditary exostosis. Discussion

Case report A 18-year-old man presented with progressive quadriparesis over 2 months. He noticed a gradually enlarging, painful neck mass. Conventional radiography showed Correspondence to: N. Sener

In the spine, a lesion with combined intradural and extradural components may lead to the so-called dumbbell mass, which passes through the corresponding neural foramen. The most common causes of spinal dumbbell lesions are schwannomas and neurofibromas, while other nerve sheath tumors, ganglioneuromas and neurofibrosarcomas are rare. Conjoined nerve roots, root

N. Yu¨nten et al.: Chondrosarcoma causing cervical neural foramen widening

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Fig. 1. Conventional radiography shows widening and calcifications at the left C5–C6 neural foramen (arrow) Fig. 2. CT scans show a calcified lesion originating from the neural arcus of C6, and causing erosive widening of the left C5–C6 neural foramen (a), producing a dumb-bell mass (b). The mass has a large, calcified paraspinal soft tissue component

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sleeve cysts, ganglion cysts, and foraminal disc herniations are relatively common conditions which can resemble nerve sheath tumors. On the other hand, some slow-growing tumors such as ependymomas, vertebral chordomas, and meningiomas may occasionally cause neural foraminal widening [1]. Rare causes include aneurysm, looping or tortuosity of the vertebral artery [2], a developmental condition associated with absence

Fig. 3. MR images show the mass with low signal on a T1-weighted sequence (a), and with high signal on a T2-weighted sequence (b). In the paraspinal soft tissue mass, strong peripheral enhancement is noted after administration of contrast medium (c). MR angiography (d) shows localized narrowing of the left vertebral artery due to compression by the mass (arrow)

of vertebral pedicle and resultant widening and craniocaudal elongation of the neural foramen [3–5], and a dumbbell lipoma [6]. Our experience with the present patient suggests that an osteochondroma or low-grade chondrosarcoma can pass through a neural foramen to produce a dumbbell lesion. The imaging findings were strongly suggestive of an osteochondroma (and malignant degeneration)

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N. Yu¨nten et al.: Chondrosarcoma causing cervical neural foramen widening

(Figs. 2, 3), enabling exclusion of the aforementioned lesions from the differential diagnosis. Osteochondroma is one of the most common benign bone tumors. With osteochondromas there is spinal involvement in less than 2 % of cases and lesions predominate in the posterior osseous elements [7]. Neurological complications such as spinal cord compression have rarely been reported either in the solitary type of osteochondroma or in multiple osteochondromas (hereditary multiple exostosis) [7–15]. Cervical cord compression is more common in the hereditary multiple form of the disease [8]. It is inherently much rarer for a chondrosarcoma to occur due to sarcomatous degeneration of a pre-existing osteochondroma [9], as malignant transformation of a solitary osteochondroma occurs with an estimated frequency of 1 % [7]. In our patient, the location, shape (cauliflower-like), and calcification pattern of the intraspinal component of the lesion suggested an osteochondroma; however, the associated large paraspinal soft tissue mass, which showed enhancement after administration of contrast medium on MR imaging, raised the possibility of sarcomatous degeneration of a pre-existing osteochondroma, prior to surgery. The lesion was confirmed by histopathological examination to be a low-grade chondrosarcoma. The possibility of multiple hereditary exostosis was excluded in this patient by clinicoradiologic investigation, outlining the condition as an exceptional case with such spinal involvement.

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