title: Acquired factor X deficiency associated with atypical AL-amyloidosis.
abstract: We herein describe the case of a 77-year-old woman with acquired factor X deficiency that was likely caused by atypical amyloidosis. The patient developed severe gastrointestinal bleeding as a result of a significant decrease of factor X activity. Neither proteinuria nor diarrhea was observed as an initial manifestation. Although a bone marrow examination revealed direct fast scarlet-positive extracellular deposits, they did not exhibit red-to-green dichroism under polarized light. Immunofluorescence microscopy showed that the fibrillar proteins were positive for CD138 but negative for β2-microglobulin or amyloid A antibodies. These atypical pathological features of immunoglobulin light chain-amyloidosis in this patient might be related to its unique clinical presentation.
authors.affiliation: Hematology Division, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Furuhata
authors.forename: Noriko
authors.initials: N
authors.lastname: Doki
authors.forename: Tsunekazu
authors.initials: T
authors.lastname: Hishima
authors.forename: Tomomi
authors.initials: T
authors.lastname: Okamoto
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Koyama
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kaito
authors.forename: Gaku
authors.initials: G
authors.lastname: Oshikawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Kakihana
authors.forename: Hisashi
authors.initials: H
authors.lastname: Sakamaki
authors.forename: Kazuteru
authors.initials: K
authors.lastname: Ohashi
mesh_terms: D000368:Aged; D000686:Amyloidosis / Q000150:complications* / Q000378:metabolism*; D005170:Factor X / Q000378:metabolism; D005171:Factor X Deficiency / Q000175:diagnosis* / Q000209:etiology*; D005260:Female; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000378:metabolism; D000685:Serum Amyloid A Protein / Q000378:metabolism*
chemical_list: D007147:Immunoglobulin Light Chains; D000685:Serum Amyloid A Protein; D005170:Factor X