PMC9674868_01
Left thumb predominant macrodactyly.
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A 26-year-old man with congenital left thumb macrodactyly (Fig. 1) presented with numbness in the left median nerve area.
(A) Axial T1-weighted magnetic resonance images through the left wrist show an enlargement of the median nerve (arrow), which exhibits a cable-like pattern; the nerve bundles are hyperintense, and the surrounding substratum is isointense relative to the muscle. (B) Coronal fat-suppressed T2-weighted images show diffuse enlargement of the median nerve from the wrist to the digits, with the swollen area in the thumb having a particularly large volume (arrowhead), which exhibits a spaghetti-like appearance; the nerve bundles are hyperintense (arrow).
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Magnetic resonance imaging (MRI) revealed marked enlargement of the left median nerve with cable-like (Fig. 2A) and spaghetti-like appearances (Fig. 2B), leading to a diagnosis of fibrolipomatous hamartoma (FLH).
(A) Axial plane ultrasound shows a typical cable-like appearance of swelling of the left median nerve (arrow), consisting of enlarged hypoechoic nerve bundles (arrowheads) and increased hyperechoic areas around those nerve bundles. (B) Sagittal plane ultrasound shows a typical spaghetti-like appearance of swelling of the left median nerve, consisting of enlarged hypoechoic nerve bundles (arrowheads). (C) Axial plane and (D) sagittal plane ultrasound show blood flow around the nerve bundles at the wrist level (arrows). Blood flow is decreased in dorsiflexion and increased in the neutral position.
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The left median nerve swelling comprised enlarged hypoechoic nerve bundles and increased hyperechoic areas around the nerve bundles, showing cable-like (Fig. 3A) and spaghetti-like (Fig. 3B) appearances. Blood flow was observed in the perineural region on superb micro-vascular imaging (Figs. 3C and D) in the neutral position.
Two enlarged nerves contiguous to the skin of the distal phalanx are cauterized and dissected.
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Since nerve blood flow was preserved at the neutral position and numbness was not severe, only debulking was performed for cosmetic reasons, and 2 enlarged nerves contiguous to the skin of the distal phalanx were cauterized and dissected (Fig. 4).