PMC7077048_01
(a) Sagittal T2 lumbar spine MRI showing multiple disc bulges at L3/L4 and L4/L5. (b) Axial T2 at the L4/L5 level showing a mild disc bulge narrowing the right nerve root foramen. (c) Axial T2 at the L5/S1 level showing mild right paracentral disc bulge.
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MRI scan was ordered; however, results did not correspond to the patient's symptomatology (Figure 1). Moreover, the patient's blood tests, including inflammatory markers (WBC, CRP, and ESR), were normal.
T2-weighted MR axial (a) and coronal (b) images of the knee at the level of the tibiofibular joint. White arrows point to the ganglion cyst extending from the STF joint, and the black arrow points to the ascending oedematous CPN. T2-weighted axial image at the level of the fibular neck (c). A horizontal, linear area of increased T2 signal along the course of the nerve represents the extension of the ING along the transverse limb of the peroneal nerve articular branch (white arrow). T2-weighted axial image above the level of the fibular neck (d) showing an intraneural ganglion cyst (white arrow) in which the tibial and peroneal divisions are separately contained (arrowheads) T: tibia; F: fibula.
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Furthermore, knee MRI showed a multilobulated lesion in the area around the fibular head, in close proximity to the common peroneal nerve (Figure 2).
Photographs demonstrating the oedematous common peroneal nerve (black arrow) intraoperatively. In (b), an incision was made in the epineurium to enable the evacuation of the mucoid content and the decompression of the nerve. Fibular head (black asterisk) and the dissected peroneus longus muscle (white asterisk) can also be seen.
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Common and deep peroneal nerves appeared oedematous (Figure 3). An incision was made to the epineurium of the common peroneal nerve and mucoid material was evacuated from the ganglion cyst (Figure 3).
Photographs illustrating the articular branch ((a) black arrow) to the superior tibiofibular joint ((b) white arrow). Transection of this branch after ligation alongside disarticulation of the superior TF joint is essential to prevent recurrence. In (a), deep peroneal nerve (black asterisk) and the peroneus longus muscle (white asterisk) can also be recognized. The peroneus longus was dissected to allow better view of the deep and superficial peroneal nerves, as well as the peroneal articular branch.
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The superior tibiofibular joint was disarticulated, and the articular branch was ligated and transected (Figure 4).
Ganglion of nerve sheath with myxoid change and cystic degeneration seen in the connective tissue of the nerve (H&E x10, x40, and x400).
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Histological examination confirmed our diagnosis of an endoneural ganglion cyst (Figure 5).
T2-weighted MR axial images of the knee at 6 months (a and b) and 10 months (c and d) postoperative in levels corresponding to preoperative views. a and c are taken at a level above the fibular head. The absence of a high signal is noted in CPN (white arrow). b and d are taken at the level in which a "transverse limb sign" was observed in preoperative MRI (black arrow). T: tibia; F: fibula.
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Subsequent knee MRI showed no signs of recurrence (Figure 6).