In amyloidoma, there will be low T1 signal with gadolinium injection and low T2 signal.The type of the amyloid protein can be determined in various ways: the detection of abnormal proteins in the bloodstream (on protein electrophoresis or light chain determination); binding of particular antibodies to the amyloid found in the tissue (immunohistochemistry); or extraction of the protein and identification of its individual amino acids. Immunohistochemistry can identify AA amyloidosis the majority of the time, but can miss many cases of AL amyloidosis. Laser microdissection with mass spectrometry is the most reliable method of identifying the different forms of amyloidosis.AL was previously considered the most common form of amyloidosis, and a diagnosis often begins with a search for plasma cell dyscrasia, memory B cells producing aberrant immunoglobulins or portions of immunoglobulins. Immunofixation electrophoresis of urine or serum is positive in 90% of people with AL amyloidosis. Immunofixation electrophoresis is more sensitive than regular electrophoresis but may not be available in all centers. Alternatively immunohistochemical staining of a bone marrow biopsy looking for dominant plasma cells can be sought in people with a high clinical suspicion for AL amyloidosis but negative electrophoresis.ATTR is now considered to be the most common form of amyloidosis, and no longer considered as a rare disease. It may be either age related in wild-type ATTR (ATTRv) or familial transthyretin-associated amyloidosis, is suspected in people with family history of idiopathic neuropathies or heart failure who lack evidence of plasma cell dyscrasias.
An intraneural perineurioma is a rare benign tumor within the sheath of a single nerve that grows but typically does not recur or metastasize. These lesions are only composed of perineurial cells, cloned from a single cell. They are distinct from schwannoma and neurofibroma. Intraneural perineurioma is a neoplastic proliferation of perineurial cells with unique immunohistochemistry and ultrastructural features, and it is distinct from other onion bulb Schwann cell-derived entities. Despite harboring molecular abnormalities of the long arm of chromosome 22, intraneural perineurioma has not been associated with neurofibromatosis.Due to the involvement of one or more nerve fascicles, intraneural perineuriomas are distinguished by a localized, solitary expansion of peripheral nerves. These tumors develop slowly or stay stable over time. References
Further reading
Macarenco RS, Ellinger F, Oliveira AM (2007). "Perineurioma: a distinctive and underrecognized peripheral nerve sheath neoplasm". Archives of Pathology & Laboratory Medicine. 131 (4): 625–36. doi:10.1043/1543-2165(2007)131[625:PADAUP]2.0.CO;2. PMID 17425397. Kum YS, Kim JK, Cho CH, Kim HK (2009). "Intraneural reticular perineurioma of the hypoglossal nerve". Head Neck. 31 (6): 833–7. doi:10.1002/hed.20965. PMID 18972430. Chung JH, Jeong SH, Dhong ES, Han SK (2014). "Surgical removal of intraneural perineurioma arising in the brachial plexus using an interfascicular dissection technique". Arch Plast Surg. 41 (3): 296–9. doi:10.5999/aps.2014.41.3.296. PMC 4037780. PMID 24883285. Emory TS, Scheithauer BW, Hirose T, Wood M, Onofrio BM, Jenkins RB (1995). "Intraneural perineurioma. A clonal neoplasm associated with abnormalities of chromosome 22". Am J Clin Pathol. 103 (6): 696–704. doi:10.1093/ajcp/103.6.696. PMID 7785653.