plexiformes Neurofibrom

Recurrent
abdominal and pelvic plexiform neurofibroma:CT and MRI findings. T2 weighted coronal image revealed paraspinal neurofibromas.
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School ager
with cafe au lait spots and upper back pain. Coronal conventional tomogram of the thoracic spine shows a soft tissue mass in the apex of the right lung causing scalloping of the right side of the upper thoracic vertebral bodies and a scoliosis convex left.The diagnosis was a paraspinal plexiform neurofibroma causing painful scoliosis in a patient with neurofibromatosis Type 1.
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Presacral
plexiform neurofibroma with urinary retention. Transverse ultrasound, pelvis. Multiple lobulated hypoechoic masses (white arrows) surround the rectum (red arrow). The rectal mucosa has normal bowel signature with no evidence of inflammation. The bladder is displaced anteriorly.
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A case of
plexiform neurofibroma associated with sphenotemporal dysplasia. Coronal view T1 after injection of contrast medium shows multiple lobulated ill-defined soft tissue lesions in the right temporal and intraorbital regions (arrows).
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Presacral
plexiform neurofibroma with urinary retention. Coronal T2 Single Shot Fast Spin Echo (SSFE), abdomen and pelvis. Large, bulky mass anterior to the lower lumbar/upper sacral spine. Multiple internal hypointense tubular structures (target sign) with rim of hyperintensity (white arrows).
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School ager
with cafe-au-lait spotsCXR PA shows a large soft tissue mass in the apex of the right lung which causes thinning of the right 1st-5th ribs posteriorly. CT without contrast of the chest shows multiple small nodules throughout the soft tissues of the chest wall.The diagnosis was multiple plexiform neurofibromas in a patient with neurofibromatosis type 1.
pediatricimaging.org • CC-by-nc-sa 4.0
Recurrent
abdominal and pelvic plexiform neurofibroma:CT and MRI findings. MRI showed pelvic and inguinal target-like lesions. Pararectal oval, midly heterogenous, hypointense neurofibromas were demonstrated.
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Recurrent
abdominal and pelvic plexiform neurofibroma:CT and MRI findings. Pararectal and pelvic neurofibromas were oval-shaped and multilobulated. Masses were hypointense-isointense in T1 weighted images, heterogenous hyperintense in T2 weighted images.
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Masses of
developmental and genetic origin affecting the paediatric craniofacial skeleton. Rapidly enlarging painful plexiform neurofibroma (PNF) in a 15-year-old girl with neurofibromatosis type 1 (NF1). Imaging was performed before PNF resection. a Panoramic view shows mandible deformity (thinning and bowing of the right ascending ramus of the mandible and the right mandibular body) with involvement and enlargement of the right inferior alveolar nerve canal (arrow). b The axial T2 images reveal extensive PNF (asterisks) with a characteristic “target sign”: central T2 hypointensity within the multilobulated hyperintense mass (arrowheads). c Gadolinium-enhanced coronal fat-saturated T1 shows large, infiltrative and multilobulated PNF involving the entire hemiface with perineural spread and extension to the right foramen ovale (arrow). d Immunohistochemistry (original magnification, ×40; S100 protein) obtained from surgical specimen highlights plexiform nerve bundles (arrows) dissecting the adipose tissue of the hypodermis (asterisk). Numerous confluent Wagner-Meissner bodies are seen (inset, original magnification, ×200; H&E stain)
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The clothes
maketh the sign. Chest radiograph (a) and coronal CT of the thorax (b) in a 25-year-old woman with cutaneous lesions demonstrating bilateral rib deformities that resemble ribbons. Well-defined erosions of either the superior or inferior margins of ribs secondary to plexiform neurofibromas and are a common manifestation of neurofibromatosis 1. The coronal CT reconstruction delineates a neurofibroma replacing the intercostal fat (b, arrow)
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Recurrent
abdominal and pelvic plexiform neurofibroma:CT and MRI findings. T2 weighted coronal image revealed pelvic target-like lesions and heterogenous hyperintense multilobulated masses.
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Recurrent
abdominal and pelvic plexiform neurofibroma:CT and MRI findings. T2 weighted coronal image revealed subcutaneus target-like neurofibromas.
www.eurorad.org • CC by-nc-sa-4.0
Recurrent
abdominal and pelvic plexiform neurofibroma:CT and MRI findings. MRI showed pelvic and inguinal target-like lesions. Pararectal oval, midly heterogenous, hypointense neurofibromas were demonstrated.
www.eurorad.org • CC by-nc-sa-4.0
Recurrent
abdominal and pelvic plexiform neurofibroma:CT and MRI findings. Pararectal and pelvic neurofibromas were oval-shaped and multilobulated. Masses were hypointense-isointense in T1 weighted images, heterogenous hyperintense in T2 weighted images.
www.eurorad.org • CC by-nc-sa-4.0
Presacral
plexiform neurofibroma with urinary retention. Axial T2 Fat-saturated Single Shot Fast Spin Echo (SSFE) through the pelvis demonstrates the large pelvic mass (white arrow) displacing the rectum and bladder anteriorly. A Foley catheter is in place (red arrow).
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Recurrent
abdominal and pelvic plexiform neurofibroma:CT and MRI findings. Contrast-enhanced CT scans revealed pararectal, subcutaneous hypodnese masses. Some of the lesions were enhancing mildly. And some of multilobulated lesions had clacifications.
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School ager
with a rapidly enlarging soft tissue mass of the right chest and armCXR PA and lateral shows a right apical thoracic mass with associated rib thinning that had rapidly increased in size in a short interval. Axial CT without contrast of the chest better defined the right apical mass and demonstrated multiple serpiginous nodules in the soft tissues of the right anterior chest wall.The diagnosis was degeneration of a plexiform neurofibroma into a malignant peripheral nerve sheath tumor in a patient with neurofibromatosis type 1.
pediatricimaging.org • CC-by-nc-sa 4.0
Recurrent
abdominal and pelvic plexiform neurofibroma:CT and MRI findings. Contrast-enhanced CT scans revealed pararectal, subcutaneous hypodnese masses. Some of the lesions were enhancing mildly. And some of multilobulated lesions had clacifications.
www.eurorad.org • CC by-nc-sa-4.0
Recurrent
abdominal and pelvic plexiform neurofibroma:CT and MRI findings. Subcutaneous multilobulated neurofibromas were observed by CT scan. Left psoas muscle and left anterior abdominal wall were not seen due to surgery the patient underwent.
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Recurrent
abdominal and pelvic plexiform neurofibroma:CT and MRI findings. Axial CT scan showed hernia of mesenteric fat tissue. Retroperitoneal well-shaped homogeneus unenhancing hypodense masses (plexiform neurofibromas) were notted. Right psoas neurofibroma was seen as hypoattenuating mass.
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Presacral
plexiform neurofibroma with urinary retention. Sagittal T2 Fat-saturated SSFE through the pelvis. The large presacral mass (white arrow) shows involvement of the adjacent sacral nerve roots (red arrow) and associated widening of the sacral neural foramen.
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Radiopaedia • CC-by-nc-sa 3.0 • de

Plexiform neurofibroma is an uncommon variant of neurofibroma, a benign tumor of peripheral nerves (WHO grade I), arising from a proliferation of all neural elements. Plexiform neurofibromas are essentially pathognomonic of neurofibromatosis type 1 (NF1). Unlike small sporadic localized neurofibromas and diffuse cutaneous neurofibromas (both discussed separately), these tumors are at significant risk of eventual malignant transformation.

Terminology

There is variable use and some confusion about the distinction between plexiform neurofibroma and diffuse cutaneous neurofibroma, with some sources not clearly distinguishing between the two. Generally, plexiform neurofibromas are deeper lesions affecting nerves and plexus. The two may, however, co-exist .

Importantly it appears that diffuse cutaneous neurofibromas may not be as closely associated with neurofibromatosis type 1 (NF1), nor have the same risk of malignant transformation . The distinction is thus important.

Epidemiology

Plexiform neurofibromas are usually diagnosed in early childhood. They are found in approximately 30% of patients with NF1.

Clinical presentation

Clinically, it presents as a subcutaneous mass which feels like a "bag of worms". Most of the time, it is a superficial cutaneous/subcutaneous lesion, but it can occur almost anywhere in the body. Symptoms may be related to local mass effect.

Pathology

Plexiform neurofibromas diffusely involve long nerve segments and its branches, often extending beyond the epineurium into the surrounding tissue.

Immunophenotype

Immunohistochemistry demonstrates findings in keeping with a neurogenic origin, including .

  • S100: positive (fewer reactive cells than in schwannoma)
  • SOX10: positive (fewer reactive cells than in schwannoma)
  • neurofilament: only positive in entrapped axons

Radiographic features

CT

Non-specific infiltrative subcutaneous lesions.

MRI

Reported signal characteristics include:

  • T1: hypointense
  • T2: hyperintense +/- hypointense central focus (target sign)
  • T1 C+: mild enhancement

Treatment and prognosis

Although generally benign tumors, there is a significant potential for malignant transformation, which occurs in 5-10% of larger tumors . If complete resection is possible, then a cure can be effected, however, due to the infiltrating nature of these tumors, such a resection is usually not possible.

History and etymology

The term plexiform comes from the infiltrative growth pattern that, histologically, looks like a plexus or a network. Plex- originates from the Latin verb plectere meaning "to plait" or "interweave".

It is typically associated with tumors of neural derivation. Plexiform neurofibromas are considered the prototype of the plexiform pattern .

Differential diagnosis

On imaging consider:

Siehe auch:
und weiter:
Assoziationen und Differentialdiagnosen zu plexiformes Neurofibrom:
Neurofibromatose
Typ 1
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