[Histopathology of lyme borreliosis].

Histological lesions due to Lyme Borreliosis are not specific and are generally characterized by a lymphocytic and plasma cell infiltrate around blood vessels. Nevertheless, the presence of plasmocytes in cutaneous annular lesions will suggest a diagnosis of Erythema migrans. The presence of tick mouthparts in an insect bite lesion is also evocative of a tick bite. If the diagnosis of lymphocytoma cutis is based on histology, only pathological clinical and biological findings will rule out a Centro follicular cutaneous B cell lymphoma. Plasma cells and ectatic vessels of cutaneous sclerous lesions may suggest acrodermatitis chronica atrophicans. Articular lesions are characterized by non-specific hypertrophic synovitis and peripheral nervous lesions by axonal neuropathy. Moreover, in situ characterization of spirochetes by silver stains or immunohistochemistry is not available in routine.