Fibrolipomatous Hamartoma and Its Ultrasound Diagnosis

Abstract

Fibrolipomatous hamartoma is a benign tumor mainly affecting peripheral nerves. It is characterized by abnormal growth of fibroadipose tissue within the nerve, leading to progressive compressive neuropathies. Carpal tunnel syndrome is the most frequent among them. Although it is considered an infrequent tumor, magnetic resonance imaging use has led to an increase in case reports. We present 3 clinical cases of fibrolipomatous hamartoma consulting due to soft tissue mass, which were diagnosed by ultrasound.

Ultrasound of Lipomatosis of Nerve Associated with Macrodactyly: ‘Spaghetti and Chocolate Cookie’ Appearance

“…The fibrous strands within the fatty tissue were seen as low-signal-intensity linear streaks on PD-w images. The thickened nerves were also seen, exhibiting characteristics as described in the literature [1][2][3][4][5][6][7].…”

“…In this paper, we focused on the US diagnosis of lipomatosis of nerve [ 5 6 7 ]. The appearance of fibrofatty tissue in the digits in macrodystrophia lipomatosa has been described previously on radiography and MRI.…”

“…Many previous case series have described the imaging of this condition [ 1 2 3 4 ]. To our knowledge, only a limited number of reports discussed ultrasound findings [ 5 6 7 ].…”

Fibrolipomatous hamartoma with macrodactyly and carpal tunnel syndrome

“…It can be diagnosed by MRI, and characteristic imaging findings include enlarged nerve bundles with low signal intensities surrounded by evenly distributed fat with high signal intensities, on T1-weighted images [ [1] , [2] , [3] ]. Ultrasound may reveal similar findings as MRI, resulting in cable-like and spaghetti-like patterns [ [3] , [4] ]. Once this characteristic image is obtained, biopsy is not necessary, and good results can be obtained with carpal tunnel release decompression alone in cases of concomitant carpal tunnel syndrome [5] .…”

Hand Masses

“…37 On US, there is a cable-like appearance with alternating hyperechoic and hypoechoic bands that are due to fibrofatty tissue and neural tissue, respectively. 39 On MRI, thickened serpiginous nerve bundles are present with surrounding fatty tissue that returns high T1 signal, giving a "spaghetti sign." 40 On axial images, the findings are reminiscent of a cut electrical cable, showing the "coaxial cable sign."…”