title: Ectopic hamartomatous thymoma: a case report with immunohistochemical study and review of the literature.
abstract: Ectopic hamartomatous thymoma (EHT) is a rare benign tumor. We present a case of EHT, which was seen as subcutaneous mass on the left supraclavicular area in a 19-year-old man. The tumor consisted of spindle cells, epithelial cells, adipose cells, and a small amount of lymphocytes, as described previously. Immunohistochemically, spindle cells were positive for keratin, a-smooth muscle actin, CD34 and vimentin, but negative for desmin and S-100 protein. Lymphocytes were positive for CD45RO but negative for CD20, CD1a, and CD99. Approximately, 5% of cells were positive for MIB-1 and no cells stained for p53 and bcl-2. Recognition of EHT is important and needs to be differentiated from high-grade sarcomas such as synovial sarcoma or glandular malignant peripheral nerve sheath tumor.
authors.affiliation: Department of diagnostic pathology, Kagawa University, Japan. ykushida@med.kagawa-u.ac.jp
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Kushida
authors.forename: Reiji
authors.initials: R
authors.lastname: Haba
authors.forename: Shoji
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Masashi
authors.initials: M
authors.lastname: Ishikawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Doi
authors.forename: Kyuichi
authors.initials: K
authors.lastname: Kadota
mesh_terms: D000071443:12E7 Antigen; D000328:Adult; D015703:Antigens, CD / Q000378:metabolism; D018949:Antigens, CD1 / Q000378:metabolism; D018951:Antigens, CD20 / Q000378:metabolism; D018952:Antigens, CD34 / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002828:Choristoma / Q000378:metabolism / Q000473:pathology*; D003937:Diagnosis, Differential; D006222:Hamartoma / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007633:Keratins / Q000378:metabolism; D017493:Leukocyte Common Antigens / Q000378:metabolism; D008297:Male; D018317:Nerve Sheath Neoplasms / Q000473:pathology; D013584:Sarcoma, Synovial / Q000378:metabolism / Q000473:pathology; D012983:Soft Tissue Neoplasms / Q000378:metabolism / Q000473:pathology*; D013945:Thymoma; D013953:Thymus Neoplasms; D014746:Vimentin / Q000378:metabolism
chemical_list: D000071443:12E7 Antigen; D015703:Antigens, CD; D018949:Antigens, CD1; D018951:Antigens, CD20; D018952:Antigens, CD34; C419393:CD1a antigen; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules; D014746:Vimentin; D007633:Keratins; D017493:Leukocyte Common Antigens