P1.025: Atypical Presentation of T-Cell Lymphoblastic Lymphoma in a 2-Year-Old: Mediastinal Mass with Pleural and Pericardial Effusions

Introduction: T-cell lymphoblastic lymphoma (T-LBL) is an aggressive malignancy that often presents with varied clinical features, typically reflecting lymphatic, thoracic, and systemic involvement. Due to its rapid progression, early recognition and prompt initiation of treatment are critical.

Case Description: A previously healthy 2-year-old male presented with a 2-week history of upper respiratory symptoms and tested positive for Mycoplasma pneumoniae and rhino/enterovirus. Initial non-contrast chest CT revealed a large left pleural effusion with mediastinal shift. The patient underwent chest tube placement followed by a video-assisted thoracoscopic surgery (VATS) performed by pediatric surgery, during which multiple pleural nodules were observed.

A subsequent contrast-enhanced CT scan revealed a large anterior and middle mediastinal mass with extension into the cervical lymph nodes, raising concern for lymphoma. Echocardiography demonstrated a moderate pericardial effusion without signs of tamponade. The patient was started on steroids and furosemide, resulting in improvement of both pleural and pericardial effusions. Biopsy of the chest wall lining confirmed T-cell lymphoblastic lymphoma, with abnormal lymphoid cells strongly positive for TdT, CD3, and CD10. Bone marrow biopsy also confirmed the diagnosis. The patient was subsequently started on a chemotherapy regimen.

Discussion: The initial non-contrast CT failed to reveal the mediastinal mass or pleural nodules, and the patient underwent anesthesia and surgery without recognition of the underlying mass. This posed potential hemodynamic risk. This case underscores the importance of using contrast-enhanced imaging in patients with significant thoracic findings to fully characterize mediastinal involvement and avoid anesthetic complications, especially in young children.

Conclusion: T-cell lymphoblastic lymphoma can present with non-specific symptoms that mimic common pediatric respiratory infections. Persistent or worsening symptoms should prompt further investigation. Clinicians should maintain a high index of suspicion and consider advanced imaging with contrast when initial evaluations are inconclusive.