title: Thymic epithelial cells as a diagnostic pitfall in the fine-needle aspiration diagnosis of primary mediastinal lymphoma.
abstract: The cytologic diagnosis of primary mediastinal lesions is challenging due to the large number of lesions which may arise (i.e., lymphoma, thymoma, germ cell tumor), often with overlapping cytomorphologic features. We present an instructive case of primary mediastinal non-Hodgkin's large-cell lymphoma with sclerosis, entrapping thymic epithelium. Preoperative fine-needle aspiration yielded predominantly epithelial fragments and few lymphoid cells leading to the cytologic misdiagnosis of thymoma. The entity of primary mediastinal large-cell lymphoma (LCL) is discussed and correlated with the cytologic features seen. In addition, histologic sections from 15 additional cases of primary mediastinal LCL were evaluated to determine the frequency with which significant numbers of epithelial fragments may be observed.
authors.affiliation: Department of Pathology, Northwestern University Medical School, Chicago, Illinois, USA.
authors.forename: G H
authors.initials: GH
authors.lastname: Yu
authors.forename: K E
authors.initials: KE
authors.lastname: Salhany
authors.forename: S T
authors.initials: ST
authors.lastname: Gokaslan
authors.forename: R S
authors.initials: RS
authors.lastname: Cajulis
authors.forename: D V
authors.initials: DV
authors.lastname: De Frias
mesh_terms: D001402:B-Lymphocytes; D001707:Biopsy, Needle; D003581:Cytodiagnosis; D003937:Diagnosis, Differential; D004848:Epithelium; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000032:analysis; D008223:Lymphoma / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D008479:Mediastinal Neoplasms / Q000175:diagnosis* / Q000473:pathology; D008875:Middle Aged; D013945:Thymoma; D013950:Thymus Gland
chemical_list: D007633:Keratins