The ultrastructural observation of a case of lymphomatoid papulosis.

Electron microscopic studies of biopsy specimens from a patient with lymphomatoid papulosis were performed. In the epidermis, infiltrating lymphoid cells, many of which had highly convoluted nuclei, were revealed to come into close contact to increased Langerhans' cells but did not accumulate to form microabscesses. In the dermis, Langerhans' cells with rather small numbers of Birbeck granules were scattered among the thick infiltration of mononuclear cells showing close apposition with lymphoid cells. Some macrophages contacted the Langerhans' cells and lymphoid cells were also observed. On one occasion, a Langerhans' cell clinged by a lymphoid cell in the uppermost dermis was revealed to expand the cytoplasm through the ruptured basal lamina touching another lymphoid cell in the epidermis.