Bone marrow histological patterns in B-cell and T-cell prolymphocytic leukemia

Area of Science:

• Hematology
• Oncology
• Pathology

Background:

• Prolymphocytic leukemia (PLL) is a rare lymphoid malignancy.
• Understanding bone marrow infiltration patterns is crucial for characterizing PLL.
• Histological patterns of bone marrow involvement can influence prognosis and treatment.

Purpose of the Study:

• To investigate and describe the histological patterns of bone marrow infiltration in prolymphocytic leukemia (PLL).
• To compare bone marrow involvement in PLL with that of chronic lymphocytic leukemia (CLL).
• To identify potential differences in histological patterns between B-cell and T-cell PLL.

Main Methods:

• Analysis of bone marrow trephine biopsies from 30 patients with prolymphocytic leukemia (16 B-cell, 14 T-cell).
• Classification of bone marrow infiltration into four histological patterns: interstitial, mixed (interstitial-nodular), mixed (interstitial-diffuse), and diffuse.
• Assessment of reticulin fibrosis in relation to histological patterns and PLL subtypes.

Main Results:

• Four histological patterns of bone marrow infiltration were observed in PLL.
• The mixed interstitial-nodular pattern was the most frequent (40%).
• PLL bone marrow involvement differs from CLL by lacking a pure nodular pattern and featuring a mixed interstitial-diffuse type.
• No significant histological pattern differences were noted between B-cell and T-cell PLL.
• Reticulin fibrosis was present in all cases, more intense in T-PLL and diffuse patterns.

Conclusions:

• Bone marrow infiltration in PLL exhibits distinct histological patterns.
• The mixed interstitial-nodular pattern is characteristic of PLL bone marrow involvement.
• Findings contribute to the characterization of lymphoproliferative disorders like PLL.