Hippokratia 2014, 18(4):376
Athanasiou A, Sarlis P, Balogiannis I
1st Department of Neurosurgery, AHEPA University Hospital, Thessaloniki, Greece
Key words: Neurofibromatosis-1, malignant peripheral nerve sheath tumor, recurrence, spinal neurofibroma
Neurofibromas are nerve sheath tumors, usually benign, of the peripheral nervous system occurring sporadically or in the context of Neurofibromatosis-1 (NFT-1), the most common neurocutaneous disorder (incidence: ~1/3000). Around 20% of NFT-1 patients will develop a plexiform neurofibroma but only 1-2% one will develop a malignant peripheral nerve sheath tumor (MPNST). No reliable screening test exists in clinical practice yet, although recently potential markers for early diagnosis have been researched.
We report an aggressive, large, MPNST of the left thigh in a 29-years-old male patient with progressive cervical myelopathy. The patient presented with tetra-spasticity, gait disturbance and instability. He also suffered from intense pain in the proximal left lower limb due to a large tumor of the medial thigh (8.8 cm in diameter), diagnosed as a plexiform neurofibroma by magnetic resonance imaging (MRI) (Figure 1). The patient had a typical clinical presentation of NFT-1 with multiple asymptomatic cutaneous, subcutaneous and spinal neurofibromas.
Figure 1: T1-weighted Magnetic Resonance Imaging of the large Malignant Peripheral Nerve Sheath Tumor of the medial thigh (5.65 x 5.25 x 8.8 cm) adjacent to, but not invading, medial vastus and sartorius muscles, a) sagittal plane and b) axial plane at greatest dimensions.
He was treated for cervical myelopathy with C2-C5 laminectomy and decompression by removal of intradural tumors and also had the thigh tumor removed en-block. Intraoperative, the thigh tumor was recognized to be larger in dimensions (11cm-diameter) than in the 2-months-old pre-op MRI. Histopathology showed a grade III-IV MPNST (CD56++, focal CD34++, and focal S100+) for the lower limb tumor, while cervical tumors were identified as typical neurofibromas. The patient was referred to an Oncological Department for further treatment but had a local recurrence within 3 months of the original operation. He was treated with excision of the recurrent lesion and also had radiotherapy sessions. He remained free of recurrence at follow-up examination (4 months from the second operation).
NFT-1 and tumor volume have been widely identified as poor independent prognostic factors regarding tumor recurrence and patient survival. Recent meta-analysis, on the other hand, has shown significant improvement of survival for NFT-1 patients with MPNST in the last ten years1. In conclusion, any new neurological symptoms in patients with plexifom neurofibromas, as well as new painful swellings in NFT-1 patients should always raise awareness for a possible MPNST2. Regular clinical and follow-up examination should not be omitted and treatment should not differ in such patients than in those cases of sporadic tumors. Neural lesions should be surgically treated when they are focal, symptomatic and resectable3, while biopsy under real-time multimodal imaging an increase in accurate detection of malignancies. Positron Emission Tomography (PET) and PET-CT in particular have had their value demonstrated regarding diagnostic accuracy in NFT-1 associated MPNSTs3.
Conflict of Interest
1. Kolberg M, Høland M, Agesen TH, Brekke HR, Liestøl K, Hall KS, et al. Survival meta-analyses for >1800 malignant peripheral nerve sheath tumor patients with and without neurofibromatosis type 1. Neuro Oncol. 2013; 15: 135-147.
2. Ferner RE, Huson SM, Thomas N, Moss C, Willshaw H, Evans DG, et al. Guidelines for the diagnosis and management of individuals with neurofibromatosis 1. J Med Genet. 2007; 44: 81-88.
3. Ferner RE, Golding JF, Smith M, Calonje E, Jan W, Sanjayanathan V, et al. [18F]2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) as a diagnostic tool for neurofibromatosis 1 (NF1) associated malignant peripheral nerve sheath tumours (MPNSTs): a long-term clinical study. Ann Oncol. 2008; 19: 390-394.