Patient X is a 32-year-old female who presents to her primary care physician with complaints of a painless swelling in her neck that has been present for the past several weeks. She reports feeling tired and having night sweats. Her medical history is unremarkable, and she takes no medications. On physical examination, the patient has a palpable lymph node in her neck measuring approximately 3 cm in diameter. She is referred to an oncologist for further evaluation. Diagnostic workup includes a complete blood count (CBC), which reveals a white blood cell count of 8,000/µL, a hemoglobin level of 11 g/dL, and a platelet count of 250,000/µL. A computed tomography (CT) scan of the neck, chest, abdomen, and pelvis shows enlarged lymph nodes in the neck and chest. A biopsy of a cervical lymph node is performed, which reveals Reed-Sternberg cells, a hallmark finding in this type of lymphoma. What disease is the likely cause of this patient's symptoms?