Birbeck granules or Birbeck junctions? Intercellular "zipperlike" lattice junctions in eosinophilic granuloma of bone.

Three cases of eosinophilic granuloma of bone exhibited intercellular attachments between histiocytes, with a pentalaminar structure identical to that seen in nearby intracellular Birbeck granules (BG). It is proposed that the term "lattice junction" be coined to describe this organelle, which seems to be expressed only by cells of monocytic-histiocytic lineage. While this finding confirms the ability of the surface membrane to form such structures, it does not necessarily preclude other intracytoplasmic sites of origin for some BG. The previously suggested role of BG in membrane storage and regulation is reiterated as a supportable model for their function.