Ultrahistopathology of balanitis circinata.

Penile lesions from six patients with balanitis circinata were examined with the light and electron microscopes. The epithelium showed slight parakeratosis, acanthosis, and elongation of rete ridges. Neutrophil pustules occupied the upper epidermis. Prickle cells formed a spongiform net around the pustules. The most prominent features detected by the electron microscope were the small-to-medium-sized pustules in the upper epidermis. The thin flattened keratinocytes formed a sponge-like trabecular network. Neutrophils were not found inside the keratinocytes. Chlamydia were not present in the lesions, which indicates that balanitis circinata is due to some reactive mechanism. The fine structure of balanitis circinata resembles that of pustular psoriasis.