RICHTER TRANSFORMATION OF T‐CELL LARGE GRANULAR CELL LEUKEMIA

Abstract

Although Richter transformation is known as transformation of B-chronic lymphocytic leukemia to diffuse large B-cell lymphoma, transformation of T-cell neoplasm is extremely rare and only several cases with transformaton of T-cell large granular cell leukemia (T-LGL) have appeared so far. We report 4 cases of CD30-positive Peripheral T-cell lymphoma, nos (PTCL-nos) that subsequently occurred in patients with T-LGL. The median age when the diagnosis of T-LGL made was 62 years old with a range from 59 to 80 years. The female/male ratio was 1:3. Interval between T-LGL and PTCL-nos ranged from 10 months to 6 years. The lesions of PTCL-nos were of generalized lymphadenopathy in 2 cases, multiple liver tumors in 1 case and right axillar lymph node swelling in 1 case. Three cases died after 1 to 6 months after transformation. Flow cytometry showed CD2 (4/4), sCD3 (4/4), CD4 (4/4), CD5 (3/4), CD8 (0/4), CD10 (0/4), CD16 (0/3), CD19 (0/4), CD30 (0/3), CD57 (1/3), TCRαβ (2/2) in T-LGL and CD2 (2/2), sCD3 (0/2), CD4 (2/2), CD5 (0/2), CD8 (0/2), CD10 (0/2), CD16 (0/2), CD19 (0/4), CD30(2/2) in PTCL-nos. In PTCL-nos, a diffuse proliferation of pleomorphic large cells with immunohistochemical expression of cCD3 (3/4), CD4 (3/4), CD5 (0/4), CD8 (0/4), CD10 (0/4), CD20 (0/4), CD30(4/4), TIA-1(3/4), Granzyme B(3/4), ALK(0/4) was observed. EBER in situ hybridization showed no positive signals in all cases of PTCL-nos. Southern blotting demonstrated same rearrangement bands of TCR-Cβ1 in both T-LGL and PTCL-nos samples (examined 2 cases). Oncoscan analysis was examined in 5 cases (2 cases of T-LGL and 3 cases of PTCL-nos) and showed that gain of 7, 12 and 17q and loss of 10 and 17p were found in PTCL-nos, but not in T-LGL. We will discuss mechanism of transformaton. It may be stated that T-cell Richter transformation was CD30(+) PTCL-nos transformed from CD4(+) T-LGL. Keywords: peripheral T-cell lymphomas (PTCL); Richter's syndrome (RS).