PMC9306749_01
Left top image. Long axis US image of patient 1. The extensive involvement of the median nerve is seen beyond the carpal tunnel. The spaghetti like appearance can be appreciated (arrows). Endoneurial fat is hyperechoic, the nerve fascicles are hypoechoic and thickened. Left bottom image. Transverse US image of third digit. Note marked increase of fatty tissue in location of digital nerve. The coaxial cable aspect is less obvious here. Right image. Sagittal PD-w MR with FS. Note the extensive 'spaghetti-like image' (arrows) comparable to US.
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F1
Lipomatosis of nerve (fibrolipomatous hamartoma) was shown as a generally rounded structure (Figures 1, 2, 3). This made the diagnosis quite difficult in for example the digital branches (Figures 1 and 3). This appearance was less obvious in the digital branches, rather an increase of hyperechoic fatty tissues in the expected location of the digital nerves was seen (Figures 1 and 3). For this appearance the MRI derived description of 'spaghetti-like' image was suitable (Figures 1 and 2). MRI confirmed the excess fibrofatty and bone tissue (Figure 1).
Left top image. US. Enlarged medial plantar nerve (arrows) in short axis next to flexor digitorum brevis in patient 2. Left bottom image. MR image in exactly the same location. The thickened medial plantar nerve can be seen as well as the medial hallucal nerve (arrow). Right image. Radiography. Macrodactyly in patient 2. The hallux is markedly enlarged with an increase in soft tissue and bony overgrowth in an irregular fashion.
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F2
Lipomatosis of nerve (fibrolipomatous hamartoma) was shown as a generally rounded structure (Figures 1, 2, 3). Of note, some difficulty was encountered in the sole of the foot due to the more limited penetration by the foot skin, and the poor differentiation from surrounding fat that is prominent in the sole of the foot (Figure 2). For this appearance the MRI derived description of 'spaghetti-like' image was suitable (Figures 1 and 2).
A. Patient 3 Top image. Transverse ultrasound image of the canal of Guyon in patient 3. Note pisiform bone (P), adjacent to it is the ulnar artery, and next to it the enlarged ulnar nerve. Middle image. Transverse ultrasound image at the level of the hook of the hamate. Note that the motor branch in the pisohamate hiatus appears relatively normal (it has been suggested motor nerves are less affected). The sensory branches are a bit flattened but the coaxial cable aspect is still obvious. Bottom image. MR imaging. Ulnar nerve in the canal of Guyon. Note markedly thickened nerve. Coaxial cable aspect is less obvious and appearance is more swirly-looking. (arrow)
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PMC9306749_01_jbsr-106-1-2849-g3.jpg
F3
Lipomatosis of nerve (fibrolipomatous hamartoma) was shown as a generally rounded structure (Figures 1, 2, 3). This made the diagnosis quite difficult in for example the digital branches (Figures 1 and 3). This appearance was less obvious in the digital branches, rather an increase of hyperechoic fatty tissues in the expected location of the digital nerves was seen (Figures 1 and 3).