162 B-Lymphoblastic Leukemia With Aberrant T-Cell Antigen (CD5) Expression: A Rare Entity. (11th January 2018)

• Record Type: Journal Article
• Authors: Mitra, Ananya Datta; Betts, Elham Vali; Rashidi, Hooman
• Is Part Of: American journal of clinical pathology. Volume 149(2018)Supplement 1
• Page Start: S69
• Page End: S69
• Publication Date: 2018-01-11
• Subjects: Diagnosis, Laboratory -- Periodicals; Pathology -- Periodicals; 616.07
• DOI: 10.1093/ajcp/aqx121.161
• Languages: English
• ISSNs: 0002-9173

Abstract

Abstract: The immunophenotypic expression of the leukemic cells in B lymphoblastic leukemia can sometimes be asynchronous and aberrant. The expression of T-cell antigens in B lymphoblastic leukemia may sometimes complicate the lineage assignment in leukemia and raises concern for ambiguous lineage acute leukemia. However, per World Health Organization criteria, T-cell lineage assignment requires CD3 expression, and in the absence of CD3, the other T-cell antigens (eg, CD2, CD5, and CD7) are generally considered as aberrancies. Here, we highlight a rare case of a 14-year-old boy presenting with fatigue, intermittent fevers, night sweats, and leukocytosis of 130 k/mm 3 with circulating blasts. Follow-up bone marrow aspirate smears showed sheets of blasts (95%; which were positive for PAX5 and TdT by immunostains, and flow cytometry profile showed abnormal B lymphoblasts with aberrant expression of CD5. Expression of CD5 in B lymphoblastic leukemia is extremely rare, and its significance remains to be seen. However, the known reported cases have suggested it to be a poor prognosticator which may be a useful marker for identifying the future patients who are at increased risk for relapse and for harboring poor cytogenetic abnormalities.