title: Immature lymphoid cells are a consistent feature of chylothorax in neonates and infants: cytologic features and flow cytometry aid in its distinction from lymphoblastic leukemia/lymphoma.
abstract: Chylothorax is rare in young children and occurs secondary to an array of etiologies. In this report, we describe the cytologic and immunophenotypic features of chylothorax in three neonates and infants. In each case, lymphocytes were the predominant cell type and had atypical cytologic features that closely resembled those of malignant lymphoblasts, including larger size, irregular nuclear contours, immature chromatin, presence of nucleoli, and high nuclear-to-cytoplasmic ratios. Flow cytometry (FC) was performed in two cases and revealed a predominant T-cell population with normal expression of T-lineage antigens and no expression of CD34, CD10, or CD1a or coexpression of CD4 and CD8. In summary, chylothorax in neonates and infants are comprised of cytologically immature lymphoid cells. In such cases, FC is useful for distinction between chylothorax and a lymphoblastic malignancy.
authors.affiliation: Department of Pathology, Arkansas Children's Hospital, Little Rock, Arkansas; Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, Arkansas.
authors.forename: Neslihan
authors.initials: N
authors.lastname: Cetin
authors.forename: Soumya
authors.initials: S
authors.lastname: Pandey
authors.forename: Robert B
authors.initials: RB
authors.lastname: Lorsbach
mesh_terms: D002916:Chylothorax / Q000473:pathology*; D003937:Diagnosis, Differential; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D016130:Immunophenotyping / Q000379:methods; D007223:Infant; D007231:Infant, Newborn; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000473:pathology; D013601:T-Lymphocytes / Q000473:pathology*
keywords: acute lymphoblastic leukemia; chylothorax; flow cytometry; lymphoblastic lymphoma; pediatric