Neurocutaneous Tumors (that's not covered already in CNS tumors) Flashcards
(32 cards)
What are the 3 types of Neurofibromas? Are they malignant?
Cutaneous neurofibroma, Solitary Neurofibroma and Plexiform Neurofibromas. Only Plexiform neurofibroma has the potential to become malignant.
How do cutaneous neurofibromas look microscopically?
Nodules (sometimes with hyperpigmentations), might become pedunculated, presents in dermis and subQ fat. No capsule but well delianated. Made of spindle cells, lots of collagen little myxoid material.
How do solitary neurofibromas differ from cutaneous neurofibroma?
It arises sparodically or in association with neurofibromatosis I, and is a neurofibroma of the Peripheral nerves.The micro is the same as the neurocutaneous version.
When do Plexiform Neurofibroma I arise?
Usually only in association with neurofibrosis type I, has a potential for malignant transformation. Can arise anywhere along a nerve.
How do plexiform neurofibromas compare with schwannomas?
In a schwannoma the tumor can dissociate from the nerve, it cannot do that in a plexiform neurofibroma because fingers of the tumor insert itself within the nerve tissue itself. Thus it has poorly defined margins.
How do plexiform neurofibromas present microscopically?
Loose myxoid background, low cellularity, mix of schwann cells (will have elongated nuclei and extensions of pink cytoplasm), fibroblastic cells (larger and multipolar), scattered inflamm cells including mast cells. Areas of collagen bundle, with “shredded carrot” appearance.
What’s the buzzword appearance of Plexiform neurofibromas?
“Shredded Carrot” appearance.
What is a “Malignant peripheral Nerve Sheath tumor?”
De novo or from plexiform neurofibroma transformation, these are highly malignant and associated with neurofibromatosis type 1.
How do Malignant peripheral nerve sheath tumors present?
Poorly defined tumor mass or masses with invasions into the nerve and adjacent soft tissues. Necrosis is common. Wide micro presentations. Mitosis, necrosis, and extreme nuclear anaplasia.
What is a “Triton Tumor?”
It is a malignant peripheral nerve sheath tumor + rhabdomyoblastic differentiation = triton tumor.
What has a strong association with Malignant Peripheral Nerve Sheath tumor?
Neurofibromatosis type I.
What is “Neurofibromatosis Type I?” (Describe the genetics)
Autosomal Dominant disease, involves the NF1 gene on chromosome 17 q11.2 and encodes the protein “Neurofibromin.”
What is the role of the protein “Neurofibromin?”
Probably plays a role in regulating signal transduction.
What are people with neurofibromatosis type I more at risk for?
Plexiform and solitary neurofibromas with a propensity for the neurofibromas to go malignant transformations more often than the general public. Also these pt’s are more prone to gliomas of optic nerve, Lisch nodules (pigmented nodules in the iris), and “cafe au lait” spots on skin.
What is the course of the disease of patients with neurofibromatosis I?
Could be anything from asymptomatic to progressive disease with spinal deformaties, disfiguring lesions and compression of vital organs.
What is the genetics behind Neurofibromatosis type II?
AD like type I but less common than type one. Involved with the NF2 gene on chromosome 22q12 (type 1 was chromosome 17). This codes for the protein “Merlin” which shows similarities to some cytoskeletal proteins.
What kind of malignancies do patients with neurofibromatosis type II develop?
Most commonly bilateral CN8 nerve schwannomas (Acoustic Neuroma) and multiple meningiomas. Ependymomas of the spinal cord also possible.
What is “schwanosis?”
Nodular ingrowth of schwann cells into the spinal cord.
What is “meningioangiomatosis?”
Proliferation of meningeal cells and blood vessels that grow into the brain.
What is “glial hamartia?”
Microscopic nodular collections of glial cells at weird locations, esp in the superficial and deep layers of the cerebral cortex.
What are the 3 non neoplastic lesions associated with Neurofibromatosis type II?
Glial Hamartia, Meningioangiomatosis and Schwanosis.
What is the triad of “Tuberous Sclerosis”?
Mental retardation, seizures and Adenoma Sebaceum.
What is “Tuberous Sclerosis?”
An AD defect that leads to the development of Hamartomas and benign neoplasms that involve the brain and other tissues.
How does Tuberous Sclerosis present and why are they called this?
Comes from the word Tubers which means potatoes, and it presents as wide, flat and firm gyri. Cortical hamartomas of TS are firm areas of the cortex and altogether resembles a potato.
