Explain the role of histiocytes in granulomas.

Many references use the confusing term histiocyte when discussing granulomas. Histiocyte may be used interchangeably with macrophage or monocyte, but the term is not specific and may be applied also to transformed lymphocytes (e.g., histiocytic lymphoma), fibroblasts that demonstrate phagocytosis (e.g., fibrous histiocytoma, reticulohistiocytoma), and antigen-presenting cells (e.g., histiocytosis X). Some authorities eschew the use of this term because it is not specific.