A 65-year-old woman comes to the office due to 2 months of lethargy. She is a reporter for the local newspaper and notes severe fatigue in the afternoons and evenings that has required her to reduce her workload. The patient has not had any fevers, night sweats, or weight changes. She does not use tobacco or illicit drugs but drinks a glass of red wine nightly. She is current on her health maintenance and does yoga 3 times a week. Temperature is 37.1 C (98.8 F), blood pressure is 112/72 mm Hg, and pulse is 88/min. The patient is thin but well nourished. There are large, firm, mobile lymph nodes in her bilateral cervical and supraclavicular chains. Cardiopulmonary and abdominal examinations are normal. Laboratory results are as follows: Peripheral blood smear reveals lymphocytosis with small, mature lymphocytes. Which of the following is the most likely diagnosis?

Question

A 65-year-old woman comes to the office due to 2 months of lethargy.  She is a reporter for the local newspaper and notes severe fatigue in the afternoons and evenings that has required her to reduce her workload.  The patient has not had any fevers, night sweats, or weight changes.  She does not use tobacco or illicit drugs but drinks a glass of red wine nightly.  She is current on her health maintenance and does yoga 3 times a week.  Temperature is 37.1 C (98.8 F), blood pressure is 112/72 mm Hg, and pulse is 88/min.  The patient is thin but well nourished.  There are large, firm, mobile lymph nodes in her bilateral cervical and supraclavicular chains.  Cardiopulmonary and abdominal examinations are normal.  Laboratory results are as follows:  Peripheral blood smear reveals lymphocytosis with small, mature lymphocytes.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

11ec25c8_d410_a42b_bc81_dd0c88657a44_MD0003_00 Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in the United States. It is almost always seen in the elderly (median age at diagnosis is 70). Patients are often asymptomatic but can present with extreme fatigue, B symptoms (eg, night sweats, fevers), infection, or weight loss. Lymphadenopathy and splenomegaly are often present on physical examination. Dramatic lymphocytosis is the classic hallmark of CLL. Peripheral smear reveals mature lymphocytes with the presence of smudge cells (a pathognomonic characteristic of CLL). smudge cells (Choice B) Chronic myeloid leukemia is a myeloproliferative disease of neutrophil lineage. Peripheral blood smear shows a massive leukocytosis with a variety of neutrophil precursor cells (eg, promyelocytes, myelocytes). This patient has a dramatic elevation in lymphocytes, not neutrophils. (Choice C) Hairy cell leukemia is a rare lymphocytic leukemia that often presents with splenomegaly and pancytopenia (including leukopenia). This patient does not have splenomegaly and her leukocyte count is very elevated, making this diagnosis unlikely. (Choice D) Hodgkin lymphoma often presents with painless lymphadenopathy and B symptoms (night sweats, fevers) in the setting of a normal peripheral blood smear and complete blood count. Massive lymphocytosis is unlikely in Hodgkin lymphoma. (Choice E) Infectious mononucleosis commonly causes lethargy in young patients, often with fever, splenomegaly, and pharyngitis. Although it can cause lymphocytosis, the white cell count is typically 12,000-18,000/mm³. This patient is elderly with severe lymphocytosis. (Choice F) Patients with lymphoblastic leukemia have a dramatic increase in blasts on peripheral blood smear. These patients also tend to be more acutely symptomatic (eg, infections due to neutropenia, bleeding due to thrombocytopenia, B symptoms, splenomegaly). Educational objective: Chronic lymphocytic leukemia is seen almost exclusively in elderly patients. Peripheral smear is characterized by a marked leukocytosis with mature lymphocytes and smudge cells.

A 65-Year-Old Woman Comes to the Office Due to 2