Chronic Eosinophilic Leukemia—Not Otherwise Specified (NOS) in the Background of a Large Cell Lymphoma

Clonal eosinophilic disorders are rare among hematological malignancies. Most eosinophilia tends to be due to secondary causes such as infections, hypersensitivity conditions, drug reactions, and connective tissue disorders. The presence of a primary clonal eosinophilic disorder such as chronic eosinophilic leukemia—not otherwise specified (NOS) in the presence of a synchronous large cell lymphoma—is rare making the diagnosis challenging. We present a case of a 51-year-old female with the aforementioned presentation and demonstrate the extensive workup performed to identify the diagnosis. 1. Introduction Non-Hodgkin’s lymphoma (NHL) is the most common hematological malignancy in the United States [1]; in contrast, clonal eosinophilic disorders are rare [2]. Lymphomas, particularly T-cell [3] and Hodgkin’s [4], can be associated with a reactive eosinophilia due to the production of various cytokines that promote eosinophil differentiation and survival. We report a rare case of a patient presenting with chronic eosinophilic leukemia in the setting of a CD30+ large cell lymphoma. 2. Case Report A 51-year-old female was referred to our medical center for evaluation of peripheral eosinophilia accompanied by a two-month history of progressive shortness of breath, fatigue, weight loss, and fevers. Physical examination demonstrated diminished breath sounds in the right lung along with bilateral cervical lymphadenopathy and hepatosplenomegaly. Further evaluation uncovered a right-sided pleural effusion which was drained and revealed an exudative fluid containing CD30+ lymphoma cells. She subsequently underwent an excisional biopsy of her cervical lymph node confirming a CD30+, CD20？, and ALK？ large cell lymphoma, favoring B-cell lineage (Figures 1(a) and 1(b)), with coexpression of CD79a, PAX-5, and MUM-1. A complete blood count during this presentation revealed a white blood cell count of 178 × 109/L, platelets of 56 × 109/L, and hemoglobin of 9.3？grams/dL. A manual differential of the white blood cells showed 4% neutrophils, 90% eosinophils (absolute count of 160 × 109/L), 1% monocytes, 1% basophils, and 4% lymphocytes. She had already been initiated on hydroxyurea at a dose of 3000？mg per day several weeks prior to our evaluation to lower the eosinophil count with no success. Her serum lactate dehydrogenase was elevated at 2,450？Units/L, and a PET/CT scan showed extensive FDG avidity in the spleen, liver, and lymph nodes around the cervical, axillary, and mesenteric regions (Figure 2(a)). A detailed review of her travel history, medication list, past medical