[6][8] However, one case of LFT-NT reported by Agaram et al was associated with metastasis, apparently as a result of the tumor's cells transformation into a malignant sarcoma.
[5] LPF-NTs have almost always been superficially situated and occurring primarily in the legs and arms with fewer cases in the head, neck, and trunk areas.
[4][6] In as high as 30% of cases, patients treated with surgical removal of the LPF-NT have presented with recurrent tumors at the site of surgery.
[2] One study found that the cells in five of five LDF-NTs overexpress, i.e. contain increased numbers of, one or more of the three Trk receptors (i.e. TrkA, TrkB, and TrkC) as judged using a pan-TRK immunohistochemistry assay.
Tumor tissues that have a histopathology compatible with LPF-NT plus spindle-shaped cells that express D34 and S100 but not SOX10 marker proteins are almost certainly LPF-NTs.
[3] The authors of many studies have suggested that one promising alternative and/or adjuvant to surgical treatment of LPF-NTs is to inhibit the action of the NTRK1 gene's product, TrkA.
Two inhibitors of receptor tyrosine kinase activity, larotrectinib and entrectinib, have been shown to be effective in phase I (screening for safety) and phase II (assessing dosage requirements and efficacy) clinical trials in patients with various types of Trk fusion gene-positive tumors although not in LPF-NTs.
[2] In 2020, a young adult presented with a spinal LPF-NT that, because of its size and location, was deemed surgically unresectable.
The treatment reduced the tumor's size by 45% within 20 weeks at which time it was removed surgically and found to consist of 95% necrotic cells.
While further clinical trials on many more individuals are needed, Tka-inhibitors may have a role as adjuvants to surgery or in various severe cases as the main treatment of LPF-NTs.