HCL is an uncommon, but distinct, lympho-proliferative disorder of B cell origin with an indolent clinical course. Less common sites of involvement by HCL include deep-seated lymph nodes, liver, bone, retroperitoneum, thyroid, etc. An accurate diagnosis of HCL depends on clinical features, as well as morphologic examination of peripheral blood smears, bone marrow and other tissues [14
]. These patients generally present with anemia, neutropenia, monocytopenia, and splenomegaly [14
]. Abdominal lymph adenopathy is unlikely to occur at the time of initial presentation; however, up to 15% of patients may develop abdominal lymphadenopathy during the course of their disease [14
The presence of lymphadenopathy noted on the recent CT scan raised the suspicion of a non-Hodgkin's lymphoma. In a study by Goodman et al, second malignancies were noted in 22% (47 patients) of HCL patients who were followed for at least 7 years [20
]. Only 3/47 (6%) patients who developed second malignancies developed non-Hodgkin's lymphoma [20
]. Most cases of lymphoma developing in patients with HCL are diffuse large B cell lymphoma [18
]. Occasional reports have also suggested transformation of HCL to other low grade B cell lymphomas [18
EUS-FNA samples on rapid assessment in the present case revealed a small to intermediate-sized monotonous population of lymphoid cells; therefore, additional samples were collected for ancillary studies to rule out possible non-Hodgkin's lymphoma. The past medical history of HCL was not available to the cytopathologist at the time of aspiration. Morphology as well as a characteristic immunophenotype on flow cytometry confirmed the diagnosis of HCL and ruled out the possibility of other B cell lymphomas which could arise in a setting of HCL. This case is an example of how multi parameter (four color) flow cytometer could provide a characteristic immunophenotype of HCL even from a small quantity of cells (total of just over 2 million cells). The new generation of flow cytometers, for example BD Facscanto (Becton Dickinson, San Jose Ca) which has a capacity for eight-parameter detection, will offer an opportunity to provide immunophenotyping on even smaller quantities of neoplastic cells.
To the best of our knowledge, there have been only four previous reports where FNA was performed in patients with HCL (see table ). In three of the four cases, a diagnosis of HCL was clinically suspected which helped establish the diagnosis of HCL on FNA samples [21
]. In one unsuspected case of HCL, FNA did not prove to be as useful in making a diagnosis of HCL [21
FNA studies performed for Hairy Cell Leukemia in the literature
Unlike percutaneous FNA, EUS-FNA obtains samples by piercing the gastrointestinal tract mucosa. Rare fragments of glandular epithelium were noted in the aspirates in the present case; however, these did not pose any concern for metastatic carcinoma. Glandular epithelium can often be seen in the EUS-FNA samples, but their characteristic honey-comb appearance and benign appearing cytologic features are helpful in avoiding possible over-interpretations[2
The patient in the present study was in complete remission with peripheral blood and differential counts remaining within the reference range. The patient had undergone splenectomy 19 years ago, and no parameters suggestive of recurrent HCL were noted in this patient. A recent review by Goodman, et al suggests that a complete remission has been noted in 50–95% of patients following 2-chlorodeoxyadenosine (2-Cda) therapy [20
]. In a more recent study, 95% of 209 patients with HCL demonstrated complete remission after 2-Cda treatment; the median time of recurrence was 42 months [20
]. In the present study, the patient was in remission for at least 4 years (48 months) following 2-Cda therapy and demonstrated abdominal pain and intra-abdominal lymphadenopathy as the first manifestation of recurrent disease.