Insidious Primary Mediastinal Large B-Cell Lymphoma in a Young Female: A Case Report and Literature Review.

Primary mediastinal large B-cell lymphoma (PMBCL) is a highly aggressive malignancy primarily observed in female patients during their third decade of life. This rare condition, with an incidence of 0.4 per million, traditionally presents with B symptoms or compressive-based sequela such as SVC syndrome or respiratory distress. In this report, we present the case of a young female who presented for palpitations and tachycardia without cardiopulmonary compressive-based symptoms diagnosed with a large 16-cm infiltrative PMBCL localized in the left ventricle.