Case 167. Lyme borreliosis (56 y-o M)
    Biopsy from erythema chronicum migrans on the abdomen around the site of tick bite, that happened in a highland of Nagano    
Key words : 
Borrelia burgdorferi, Lyme disease, erythema chronicum migrans    
A centrifugally spreading erythematous lesion (migrating erythema) is seen around the site of tick bite (left-sided abdomen). At the 6th week, the erythema reached the chest wall (gross findings).   Five days later, the erythema involved the neck and thigh (gross findings). One week later (at the 8th week), the erythema disappeared spontaneously.
Histologic features are nonspecific. Perivascular infiltration of small lymphocytes and some plasma cells is seen in the entire thickness of the dermis (HE). Warthin-Starry's silver was negative.   Electron micrograph of Borrelia burgdorferi isolated from the skin lesion of Lyme borreliosis
Negative staining observation shows morphology of loosely coiled Spirocheta. Compare the ultrastructural morphology of Borrelia with that of Leptospira as shown in case 154.