A46-16 Chylothorax as a Manifestation of CLL Recurrence in an OHT Patient

Abstract Introduction Chronic lymphocytic leukemia (CLL) is an indolent B-cell neoplasm defined by a clonal population of B lymphocytes in the peripheral blood. Classic manifestations include lymphocytosis, anemia, thrombocytopenia, lymphadenopathy, and hepatosplenomegaly. Recurrence is common and is usually diagnosed by exam and laboratory evaluation alone. Case Report An 80-year old man with a history of CLL, ischemic cardiomyopathy s/p orthotopic heart transplant (OHT) in 2021, complicated by recurrent cutaneous squamous cell carcinomas (SCCs), presented for progressive dyspnea. His CLL was initially diagnosed in 2001, treated with bendamustine and rituximab (BR), with recurrence in 2006, achieved remission again with BR. Peripheral blood analysis and CT chest abdomen pelvis in 2021 re-OHT showed no evidence of CLL recurrence. He underwent OHT in 2021 with post-transplant course complicated by recurrent cutaneous SCCs requiring Mohs surgeries and necessitating de-escalation of his immunosuppression. In October 2025, he presented with subacute dyspnea. He had normal vital signs and baseline basic laboratory testing. A chest x-ray demonstrated a new left pleural effusion. Thoracentesis was performed; 1.5L of milky white fluid was removed. Pleural fluid analysis revealed lymphocytic predominant exudative (by LDH criteria) fluid, with a triglyceride count of 1,276 mg/dL. He underwent lymphangiogram demonstrating sluggish antegrade lymphatic flow with no evidence of thoracic duct leak. Cytology was negative but pleural fluid flow cytometry demonstrated a small population of lambda-restricted B-cells. Complete blood counts were at baseline, including absolute lymphocyte count. Computed tomography of the chest, abdomen and pelvis did not demonstrate any abnormal lymphadenopathy nor hepatosplenomegaly. The patient underwent peripheral flow cytometry, which revealed a monotypic B-cell population (11% of total) expressing CD5, CD23, and CD200, consistent with CLL recurrence. Cytogenetics was normal. He was started on obinutuzumab, in addition to a high-protein, low-fat medium-chain triglyceride diet with symptomatic monitoring of his pleural effusion, anticipating improvement with CLL treatment. Discussion Chylothorax is rarely seen in CLL but should be considered as a sign of relapse in patients with a prior history. This patient’s use of immunosuppression for OHT reduced host immune surveillance and increased risk of malignancy recurrence. These medications similarly mask typical laboratory findings monitored for CLL surveillance (total white blood cell count and absolute lymphocyte count), while also increasing the risk for transformation to diffuse large B cell lymphoma. Chylothorax is considered a symptomatic manifestation of CLL warranting treatment; however, little is known regarding the role of dietary modifications and somatostatin analogues in this patient population and warrants investigation. This abstract is funded by: None