Also known as: Bone cancer
A young sailor is diagnosed with lymphoid sarcoma in her humerus (arm bone). The cancer has already spread to lymph nodes in her neck, requiring amputation of her arm despite her refusal, as she wanted to complete a solo sailing record attempt. The case drives the central ethical conflict of the episode.
The lymphoid sarcoma causes a paraneoplastic syndrome resulting in third-degree heart block and bradycardic arrest, which is temporarily resolved with calcium chloride and used as justification for emergency surgery.
Also known as: Huntington's disease
Thirteen mentions having Huntington's disease when explaining why she's had multiple lumbar punctures. This is part of her ongoing character health arc and explains her absence from the hospital.
Also known as: Salmonella infection
Initially suspected as the cause of Kendall's symptoms, salmonella enteritis from poultry exposure is ruled out as the diagnosis before the lymphoid sarcoma is discovered.