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.
Keywords:
Alveolar soft part sarcoma; CD68; brain metastasis.
Publication types
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Case Reports
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Research Support, N.I.H., Extramural
MeSH terms
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Adolescent
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Antigens, CD / metabolism
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Antigens, Differentiation, Myelomonocytic / metabolism
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Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / genetics
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Brain Neoplasms / diagnosis
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Brain Neoplasms / secondary*
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Brain Neoplasms / ultrastructure*
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Carcinoma, Renal Cell / diagnosis
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Diagnosis, Differential*
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Humans
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Immunohistochemistry
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In Situ Hybridization, Fluorescence
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Intracellular Signaling Peptides and Proteins
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Leg / pathology
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Male
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Microscopy, Electron, Transmission
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Oncogene Proteins, Fusion / genetics
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Recombinant Fusion Proteins / genetics
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Sarcoma, Alveolar Soft Part / diagnosis*
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Sarcoma, Alveolar Soft Part / secondary*
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Sarcoma, Alveolar Soft Part / ultrastructure*
Substances
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ASPSCR1 protein, human
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Antigens, CD
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Antigens, Differentiation, Myelomonocytic
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Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
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CD68 antigen, human
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Intracellular Signaling Peptides and Proteins
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Oncogene Proteins, Fusion
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Recombinant Fusion Proteins
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TFE3 protein, human