Ectopic hamartomatous thymoma: a case report showing CD99+ lymphocytes and a low proliferation index.
Ectopic hamartomatous thymoma is a rare benign tumor that consists of spindle, epithelial, and adipose cell elements. We present a case of this lesion arising in the supraclavicular region of a 59-year-old man, including the characteristic immunohistochemical and ultrastructural findings. DNA flow cytometry revealed diploidy with a low proliferation index (6.73%). The tumor contained CD99+ lymphocytes; CD99 (MIC2) can serve as a useful marker of immature T cells. These findings suggest that ectopic hamartomatous thymoma may develop from the third branchial pouch or thymic anlage.
Lee
Shi Nae
SN
Department of Pathology, Medical College, Ewha Womans University, Seoul, South Korea.
Cho
Min Sun
MS
Koo
Heasoo
H
Han
Woon Sup
WS
D000071443:12E7 Antigen; D015703:Antigens, CD / Q000032:analysis; D018952:Antigens, CD34 / Q000032:analysis; D017252:CD3 Complex / Q000032:analysis; D015815:Cell Adhesion Molecules / Q000032:analysis; D002455:Cell Division; D002828:Choristoma / Q000378:metabolism / Q000473:pathology*; D006222:Hamartoma / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000032:analysis; D017493:Leukocyte Common Antigens / Q000032:analysis; D008214:Lymphocytes / Q000737:chemistry / Q000473:pathology; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D008940:Mitotic Index; D018396:Mucin-1 / Q000032:analysis; D013945:Thymoma / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D013953:Thymus Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure
D000071443:12E7 Antigen; D015703:Antigens, CD; D018952:Antigens, CD34; D017252:CD3 Complex; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules; D018396:Mucin-1; D007633:Keratins; D017493:Leukocyte Common Antigens