Teaching Case

A 30-year-old male presented with a 1-year history of intermittent head and neck pain, walking difficulties, difficulty concentrating and periods of confusion. On neurological examination, there was a slight decrease in fine motor function of the hands and a very slow tandem gait.

Non-enhanced CT of the cervical spine (Fig. 1A and 1B) showed a well-circumscribed mass with large intratumoral calcifications eroding the second and third cervical vertebrae and extending into the spinal canal. On cervical spine MRI (Fig. 1C and 1D), the mass was heterogeneous, predominantly hyperintense on T2 (Fig. 1C), isointense on T1, and demonstrated heterogeneous contrast-enhancement (Fig. 1D). A severe spinal stenosis was seen, with deformation of the cervical spine and signs of myelopathy. Of note, the mass caused displacement of the paravertebral tissues (e.g. left vertebral artery), but did not show signs of invasive growth.

Ossifying fibromyxoid tumor (OFT).  is a rare tumour of the soft tissues which most frequently occurs in the extremities and trunk [1]. Clinically, it typically presents as a slowly enlarging painless mass in the subcutaneous tissues or skeletal muscle, with a median (range) age of presentation of 50 (14-83) years [2]. A slight male predilection has been reported [1,2]. Since its description in 1989, studies have tried to establish an exact cell lineage, ranging from neuroectodermal, myoepithelial, to osteo- or chondroblastic [3,4]. However, as of yet, the histogenesis remains uncertain, and, as a result, it is classified as a neoplasm of uncertain differentiation [4]. Of note, although most tumours behave in a benign manner, some demonstrate malignant or atypical feature [5]. Almost no cases with vertebral or spinal involvement have been described in the literature.

In the current case, a benign and slow-growing tumour seemed the most likely diagnosis, and the main differential diagnosis consisted of a calcified ‘ancient’ schwannoma, meningioma or a chondroid tumour arising from the intervertebral joint (although the enhancement pattern was atypical). A resection was performed and based on histopathology and histochemistry the lesion was diagnosed as an OFT.

A paucity of data exists on the imaging characteristics of these tumours [6,7]. On plain radiographs, it presents as a mass with an incomplete rim of ossification, and less often central ossification can be seen. On CT imaging these ossifications are seen more clearly, and, as a result, more often. On MRI the tumour is isointense on T1-weighted imaging and intermediate-to-high on T2-weighted imaging. Areas of high signal on T1- and T2-weighted can be present, which are thought to be related to haemorrhage. [8,9] Furthermore, on technetium scans the presence of intratumoural mature bone formation can be visualised [7]. However, it should be noted that mature bone is absent in approximately one-third of cases, as was the case for the current tumour (based on pathology).

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