A 50 Year Old Man Presents With Fatigue And Easy Bruising

A 50 year old man presents to his primary care physician with complains of fatigue and recently noticed having bruises after minor trauma. Although he has never taken his temperature he feels that he has low grade fever on and off over the last few months.
On Examination he was noticed to have an enlarged spleen and few bruises.
His blood workup showed low RBC, WBC and platelet count. The peripheral smear is shown below:

 What is the Diagnosis?
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Hairy cell leukemia


Case Discussion:
Hairy cell leukemia is a chronic lymphoid cell leukemia and is named because the abnormal cells have hair like cytoplasmic projections on its surface. These abnormal cells infiltrate the patients reticuloendothelial system and interferes with normal bone marrow function.

Etiology: The exact cause of hairy cell leukemia is still not determined but it is suggested to be secondary to exposure to certain chemicals like benzene and radiation exposure.

Clinical Features:
Some patients may have no signs or symptoms while others may present with:

• Fatigue
• Easy bruising
• Recurrent infection
• Weakness
• Weight loss
• Splenomegaly

Diagnosis:

• The peripheral blood cell counts shows pancytopenia with decreased cell counts in all three cell lines. 
• The typical hairy cells of hairy cell leukemia are so named because of their characteristic cytoplasmic projections, which appear as fine (hairlike) microvilli when seen by light microscopy, phase contrast microscopy and electron microscopy. These are mononuclear cells with eccentric or centrally placed nuclei.
• The bone marrow aspirate usually results in a dry tap. 

Treatment:

Since the disease is slow in progression and sometimes with no symptoms , treatment is not necessary for all patients. Patients initially just need close observation but eventually may need some sort of treatment. 

Chemotherapy is the first line and the drugs used are Cladribine, Pentostatin, interferons etc. 

Surgery to remove the enlarged spleen may be need in some patients.