Kikuchi-Fujimoto disease is a rare, benign, and self-limited disease of uncertain etiology, affecting mostly young female patients. It usually manifests as posterior cervical lymphadenopathy and fever. Its diagnosis is based on typical histopathological changes after the exclusion of other diseases such as lupus, lymphoma, or infectious lymphadenitis. The authors present a 47-year-old female patient with recurring episodes of high fever, urticarial rash, myalgia, arthralgia, fatigue, sore throat, and generalized lymphadenopathy. Blood tests showed increased inflammatory parameters and positive antinuclear antibodies. In the two times the patient was admitted to the hospital there were no infectious agents isolated. The patient didn't fulfill the criteria for diagnosis of lupus or any other autoimmune disease and there was also no evidence of lymphoma or other neoplastic diseases. A positron emission tomography/computed tomography (PET/CT) was performed at the first and second hospitalizations, showing generalized lymphadenopathy. At the first hospitalization, a mediastinal lymph node biopsy was obtained, excluding lymphoproliferative or granulomatous disease. During the course of the second hospitalization, a cervical lymph node was excised for biopsy, the histopathological changes of which suggested the diagnosis of Kikuchi-Fujimoto disease. The clinical course was complicated by hemophagocytic lymphohistiocytosis, with a significant increase in inflammatory markers and liver dysfunction. The patient was treated with prednisolone 1 mg/kg/day, with complete resolution of clinical and biochemical changes.

Anti-N-methyl-D-aspartate receptor (Anti-NMDAR) encephalitis is a rare autoimmune disease, characterized by the presence of neuropsychiatric symptoms. It is sometimes mistaken for a psychiatric disorder and other times not considered in the differential diagnosis of an encephalitic process. Correct identification of this disease and prompt treatment are key for optimal recovery, which might take weeks to months. Many patients manifest severe symptoms, with depressed level of consciousness, breathing dysfunction and dysautonomia requiring admission to the Intensive Care Unit (ICU). We report the case a young male patient with anti-NMDA encephalitis who presented typical neuropsychiatric symptoms. Despite being diagnosed and treated in a timely manner, he did not respond well to first-line immunotherapy and was admitted to the ICU with neurological, respiratory, and cardiovascular dysfunction. This resulted in prolonged hospital admission and many infectious complications. Despite the severity of the disease, the patient managed to recover in the months following discharge from hospital.