Histiocytic necrotizing lymphadenitis without granulocytic infiltration

Twenty-seven cases of an unusual necrotizing lymphadenitis previously described only in Japan are reported as occurring in West Germany (23 cases), Iran (1 case), Italy (1 case), Korea (1 case) and Spain (1 case). The lesion frequently develops in the cervical lymph nodes of young women. It is characterized by infiltration of the cortex and/or paracortex by large collections of proliferating histiocytes and is devoid of granulocytes. Complete or, more often, incomplete necrosis of lymphoid tissue is seen in all cases. In cases with incomplete necrosis, the histiocytes are interspersed with pyknotic cells and nuclear debris. Based on the histological findings, the term "histiocytic necrotizing lymphadenitis without granulocytic infiltration" is proposed. Lesions to be considered in a differential diagnosis are malignant histiocytic neoplasms and necrotizing lymphadenitis with granulocytic infiltration, which is seen in lupus erythematosus and bacterial infections. The aetiology of histiocytic necrotizing lymphadenitis without granulocytic infiltration is still unclear. Some clinical and histological features indicate the possibility of an underlying viral infection.