title: Brain metastasis of crystal-deficient, CD68-positive alveolar soft part sarcoma: ultrastructural features and differential diagnosis.
abstract: We report a case of alveolar soft part sarcoma (ASPS) presenting as an isolated frontal lobe metastasis. The tumor demonstrated little or no immunoreactivity for a broad panel of antibodies yet strong, diffuse immunoreactivity with CD68. On electron microscopy, the characteristic rectangular to rhomboid crystalline inclusions of ASPS were not present. Electron-dense granules resembling peroxisomes were present, sometimes in association with elongated granular structures having a periodic, lattice-like arrangement. Metastatic ASPS was confirmed by demonstration of an ASPSCR1-TFE3 fusion and imaging studies that excluded metastatic Xp11.2 translocation renal cell carcinoma. The primary site was subsequently identified in the lower extremity.
authors.affiliation: Department of Pathology and Genomic Medicine, Houston Methodist Hospital , Houston, TX , USA .
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Cykowski
authors.forename: John
authors.initials: J
authors.lastname: Hicks
authors.forename: David I
authors.initials: DI
authors.lastname: Sandberg
authors.forename: Adriana
authors.initials: A
authors.lastname: Olar
authors.forename: Julia A
authors.initials: JA
authors.lastname: Bridge
authors.forename: Patricia T
authors.initials: PT
authors.lastname: Greipp
authors.forename: Patricia
authors.initials: P
authors.lastname: Navarro
authors.forename: Steven
authors.initials: S
authors.lastname: Kolodziej
authors.forename: Meenakshi B
authors.initials: MB
authors.lastname: Bhattacharjee
mesh_terms: D000293:Adolescent; D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000235:genetics; D001932:Brain Neoplasms / Q000175:diagnosis / Q000556:secondary* / Q000648:ultrastructure*; D002292:Carcinoma, Renal Cell / Q000175:diagnosis; D003937:Diagnosis, Differential; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D047908:Intracellular Signaling Peptides and Proteins; D007866:Leg / Q000473:pathology; D008297:Male; D046529:Microscopy, Electron, Transmission; D015514:Oncogene Proteins, Fusion / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics; D018234:Sarcoma, Alveolar Soft Part / Q000175:diagnosis* / Q000556:secondary* / Q000648:ultrastructure*; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D047908:Intracellular Signaling Peptides and Proteins; D015514:Oncogene Proteins, Fusion; D011993:Recombinant Fusion Proteins; C422743:ASPSCR1 protein, human; C067980:CD68 antigen, human; D000097382:CD68 Molecule; C069203:TFE3 protein, human
keywords: Alveolar soft part sarcoma; CD68; brain metastasis