Necrotizing lymphadenitis of the neck (Kikuchi's disease).

Kikuchi's histiocytic necrotizing lymphadenitis is a benign condition originally described in the Japanese literature in 1972. We here describe the clinicopathological features, including fine needle aspirate and bone marrow biopsy, of a case of Kikuchki's disease, which to our knowledge is the first reported from a Scandinavian country. The histopathological features of the enlarged lymph nodes were documented by multiple small necrotic foci showing karyorrhectic debris and haemorrhage. The necrotic foci were surrounded by a mantle of large histiocytic-like cells with vesicular nuclei and clear cytoplasm. The nodal architecture was almost completely effaced and the node infiltrated by a mixture of lymphoid cells of variable size. Neutrophils, eosinophils, and plasma cells were very few. The fine needle aspirate biopsy showed a mixture of small dark lymphocytes, larger activated lymphocytes, and many histiocytes. The bone marrow biopsy showed normal haematopoiesis but some large cells with phagocytosed leukocytes, i.e. similar to haemophagocytosis. Kikuchi's disease has a predilection for lymph nodes in the neck of young women, and is usually self-limited and subsides in 1 to 4 months. The patient described in this report received no treatment. Within 5 weeks the fever subsided and the lymph nodes diminished in size. One year later the patient is well and free of disease. We emphasize the benign nature of Kikuchi's disease, and that SLE and malignant lymphoma are the majori differential diagnoses.