[Relapsing meningitis and confusion: limbic encephalitis revealing Hodgkin's disease]

Voltage-gated potassium channel antibody paraneoplastic limbic encephalitis associated with acute myeloid leukemia

Among paraneoplastic syndromes (PNS) associated with malignant hemopathies, there are few reports of PNS of the central nervous system and most of them are associated with lymphomas. Limbic encephalitis is a rare neurological syndrome classically diagnosed in the context of PNS. We report the case of a 81-year-old man who presented with a relapsed acute myeloid leukemia (AML) with minimal maturation. He was admitted for confusion with unfavorable evolution as he presented a rapidly progressive dementia resulting in death. A brain magnetic resonance imaging, performed 2 months after the onset, was considered normal. An electroencephalogram showed non-specific bilateral slow waves. We received the results of the blood screening of neuronal autoanti-bodies after the patient's death and detected the presence of anti-voltage-gated potassium channel (VGKC) antibodies at 102 pmol/l (normal at <30 pmol/l). Other etiologic studies, including the screening for another cause of rapidly progressive dementia, were negative. To our knowledge, this is the first case of anti-VGKC paraneoplastic limbic encephalitis related to AML.

Hodgkin's disease presenting as discharging neck sinuses and a mediastinal mass

A 23-year-old Asian lady presented with a hard indurated midline neck swelling of 2 months duration without any upper aerodigestive tract or systemic symptoms of note. Her inflammatory markers were elevated and she was commenced on antibiotics. Ultrasound scan and fine needle aspiration cytology (FNAC) were inconclusive. A CT scan showed an ill-defined soft tissue mass anterior to and not well demarcated from the thyroid, and contiguous with a superior and anterior mediastinal mass. Incisional biopsy revealed necrosis and pockets of purulent material. Microbiology suggested a chronic pyogenic abscess negative for acid fast bacilli. She was treated with antituberculous therapy without resolution. She developed a discharging lateral neck mass with progressive increase of the mediastinal mass. She subsequently required a neck exploration and mediastinoscopy. Repeat mediastinal biopsies confirmed the diagnosis of Hodgkin's disease and no organisms on culture. She was commenced on chemotherapeutic treatment with a satisfactory outcome.