Fibrolipoma. Reply.

We are very grateful for the comments and constructive suggestions made by Mark A. Mahan et al. regarding our recent article1. The critical review provides better knowledge regarding lipomatous lesions of the nerves2. However, in our manuscript we do not discuss the broad but interrelated spectrum of lipomatous lesions of the nerves. We have reviewed our magnetic resonance images and found that the lesion appeared to have homogeneous low signal intensity on T1-weighted images and dishomogeneous hyperintensity on T2-weighted images. In the sagittal sequences, the T-6 nerve, which was very thin and stretched, was detectable in its intra-foraminal and extra-foraminal course and completely surrounded by pathological tissue, as a single strand. An abnormal area of high signal intensity in the vertebral body of T6 was evident on T2-weighted images. After the addition of contrast medium, the lesion exhibited dishomogeneous enhancement. In the surgical theater, the T6 nerve was found to be completely embedded inside the lesion. The distal portion of the nerve emerged from the lesion, and the proximal stump of the nerve emerged only after total resection of the tumor. The lesion did not invade the bone, which had a normal appearance without any sign of infiltration. We interpreted this finding as a reaction (edema) of the bone marrow to the fibrous-fatty tissue, which persisted, though to a lesser extent, in the postoperative MRI performed a few days ago, without any recurrence. The histological specimen showed a very poor vascular network, not allowing the utilization of the adjective “vascular”, and consequently angiofibrolipoma. In contrast, fibrous connective tissue was abundant and perineural fibrosis evident. We maintain our diagnosis of neural fibrolipoma of the T-6 nerve but think that additional cases in the spinal cord could enhance our knowledge of this rare entity, as well as lipomatous lesions of the nerves.