Content area
Full Text
Key Words: Monoclonal B-cell lymphocytosis; MBL; CLL; Bone marrow histology
DOI: 10.1309/AJCPPHSUQM8XBJH7
Upon completion of this activity you will be able to:
* recognize the bone marrow trephine histologic findings in monoclonal B-cell lymphocytosis.
* advise the clinician about the implication of diagnosing lesions in bone marrow trephines that are consistent with monoclonal B-cell lymphocytosis.
The ASCP is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The ASCP designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 Credit (TM) per article. Physicians should claim only the credit commensurate with the extent of their participation in the activity. This activity qualifies as an American Board of Pathology Maintenance of Certification Part II Self-Assessment Module.
The authors of this article and the planning committee members and staffhave no relevant financial relationships with commercial interests to disclose
Questions appear on p 399. Exam is located at www.ascp.org/ajcpcme.
Abstract
Monoclonal B-cell lymphocytosis (MBL) is defined as less than 5 × 109/L monoclonal B cells in the blood of otherwise healthy patients and is detected in 5% to 10% of individuals older than 60 years. The bone marrow findings in MBL have hitherto not been systematically described. We have studied the histologic and immunophenotypic findings in paired trephine biopsy specimens and bone marrow aspirates of 26 patients with MBL. Abnormal lymphoid infiltration was detected in trephine biopsy specimens of 20 patients and was demonstrated by flow cytometry of bone marrow in all 26 patients. Three infiltration patterns were discerned: focal interstitial lymphoid infiltration, focal rounded and nonparatrabecular lymphoid aggregates, and discrete diffuse lymphocytosis. Focal interstitial lymphoid infiltration was seen only in patients with chronic lymphocytic leukemia (CLL)-like or atypical CLL-like MBL, whereas the other patterns were not related to a particular MBL immunophenotype. Our results show that most patients with MBL also have bone marrow lymphoid infiltration. The latter should be distinguished from lymphoma infiltration by clinical correlation.
Monoclonal B-cell lymphocytosis (MBL) was first recognized as an indolent variant of chronic lymphocytic leukemia (CLL) in patients with Rai stage 0 disease. The patients showed no disease progression, even after a period of more than 24 years.1 A similar indolent form of CLL was later described...