a Rare Case of Chronic Lymphocytic Leukemia (CLL), Transforming to Two Different Types of Aggressive Lymphoma during the Course of the Disease.
Authors: Azadi Amir , Moffett Padmini , Mandadi Mounika , Kloecker Goetz H 
Published: October 2019

Abstract
A rare case of chronic lymphocytic leukemia (CLL), Transforming to two different types of aggressive lymphoma during the course of the disease.
BACKGROUND
Patients with chronic lymphocytic leukemia may have disease transformation to non-Hodgkin's lymphoma (DLBL)or prolymphocytic leukemia (PLL)
To date there have been no cases in the english literatures reporting a CLL patient presenting with transformation to both of these different types of more aggressive diseases during the course of their disease. We describe a rare case of CLL who developed transformation to PLL and DLBL, also known as Richter's transformation(RT) respectively during the course of disease.
CASE
A 53 year old woman with no significant prior medical history who initially presented with leukocytosis of 14500 and cervical lymphadenopathy on physical examination. Excisional biopsy and microscopic examination confirmed the diagnosis of chronic lymphocytic leukemia with microscopic features of monotonous population of small mature-appearing lymphocytes. Immunohistochemical studies are positive for CD5 and CD23, CD38 and ZAP 70. Concurrent review of peripheral blood smear was showed leukocytosis with relative lymphocytosis and smudge cells. A computed tomography scan of the neck, chest, abdomen and pelvis performed and was remarkable for cervical lymphadenopathy and she was subsequently staged as RAI I of CLL/SLL.
The patient was asymptomatic and was therefore observed expectantly for 10 months. Then due to progression of lymphocytosis and extensive cervical lymphadenopathy, she began treatment with chemotherapy consisting of Rituxan, Cytoxan and Fludarabine. After 18 months of being in remission after treatment she again developed cervical lymphadenopathy and night sweats.
Exisional biopsy of left cervical lymph node performd and flow cytometric analysis of the lymph node was positive for CD-20, PAX-5, and BCL-2 . Also 97% of these B cells expressed CD38, which is associated with a more aggressive course in CLL, and was supportive for prolymphocytic transformation of CLL. She has been initiated on chemotherapy including bendamustine and Rituxan for a total of four cycles.
Patient had a good response to treatment for nine months until she palpated a lymph node in left submandibular area and subsequent excisional lymh node biopsy showed recurrence of the disease with prolymphocytic transformation. The patient began to receive chemotherapy with (R-CHOP) regimen after confirmation of recurrence. A month after completion of chemotherapy, patient had developed increasing lymphadenopathy in neck.
Microscopic exam of the biopsy showed foci of CLL/SLL cells and Some binucleated large cells with Immunohistochemical stains, positive for CD20 and weak positivity for CD5 and negativity for CD23, CD10 and BCL6. Immunohistochemical stain for KI-67 shows 70-80% proliferation rate in large cells and less than 10% proliferation rate in background CLL cells which indicates Richter's transformation of CLL/SLL to diffuse large B-cell lymphoma with an activated B-cell phenotype, which is the most common histologic variant of Richter transformation.
CONCLUSION
Chronic lymphocytic leukemia(CLL) is an indolent B-cell non-Hodgkin's lymphoma and is the most
common leukemia in the western world with a heterogenous and mostly prolonged disease course, that may transform into higher grade lymphoma. Transformation of CLL to a more aggressive lymphoma occurs in about 5-10% of patients, and is generally accociated with acceleration of the disease and poor clinical prognosis. The transformation involves an increased number of Prolymphocytic cells, termed PLL transformation or the development of DLBCL which also reffered to as Richter's transformation.

Disclosures
No relevant conflicts of interest to declare.