Malignant peripheral nerve sheath tumors associated with neurofibromatosis type 1: report of two clinical cases.
BACKGROUND
Malignant peripheral nerve sheath tumor (MPNST) is a sarcoma with a high grade of malignancy originating in the nerve sheath components, fibroblasts, perineural cells, and Schwann cells. It is associated with neurofibromatosis type 1 (NF-1) with a risk of 10-13%.


METHODS
We present two cases of NF-1-associated MPNST. The first patient presented moderate pain with no apparent cause, in addition to the presence of intraspinal lesion demonstrated by nuclear magnetic resonance imaging (NMRI), which was managed surgically on two occasions. Histologically, it corresponded to a neurofibromatosis lesion in transition with malignant neoplasm. The second case manifested with thoracic kyphoscoliosis, pain, and an increase in volume. Associated with the deformity, MRI showed a withering tumor in the posterior thoracic region (T1-T8), observing an infiltrating, cellular sarcomatous neoplasm with immunopositivity for S-100 protein and vimentin.


CONCLUSIONS
MPNSTs are sarcomas with a high index of recurrence with the ability to produce distant metastasis during early stages. Despite wide resection, patients did not survive due to the advancement and size of the lesions (determining factors in the prognosis). Due to the progressive growth of MPNST and the anatomic difficulty for its approach, there should be strict surveillance of patients with NF-1 for early detection of malignant transformation in these lesions.
del Carmen Baena-Ocampo
Leticia
L
Servicio de Anatomía Patológica, Instituto Nacional de Rehabilitación, Secretaría de Salud, México, D.F., Mexico.
Reyes-Sánchez
Alejandro
A
Alpízar-Aguirre
Armando
A
Rosales-Olivares
Luis Miguel
LM
D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis; D002574:Cervical Vertebrae; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000209:etiology; D007796:Laminectomy; D008279:Magnetic Resonance Imaging; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000532:radiotherapy; D009408:Nerve Compression Syndromes / Q000209:etiology; D018317:Nerve Sheath Neoplasms / Q000737:chemistry / Q000150:complications / Q000235:genetics* / Q000601:surgery; D009456:Neurofibromatosis 1 / Q000473:pathology*; D009418:S100 Proteins / Q000032:analysis; D012600:Scoliosis / Q000209:etiology; D013125:Spinal Neoplasms / Q000737:chemistry / Q000150:complications / Q000235:genetics* / Q000601:surgery; D013126:Spinal Nerve Roots; D013904:Thoracic Vertebrae; D014746:Vimentin / Q000032:analysis; D055815:Young Adult
D014408:Biomarkers, Tumor; D009418:S100 Proteins; D014746:Vimentin