The first human case of hepatic dirofilariasis.

Most of human dirofilariasis are pulmonary or subcutaneous infections, but there have been a few reports of human dirofilariasis in unusual sites, such as large vessels, mesentery, peritoneal cavity, and spermatic cord. We present the first case of human hepatic dirofilariasis, which was surgically diagnosed. A 39-year-old man without any evidence of systemic symptom was found incidentally to have a hepatic nodule during routine physical check-up. The histologic findings of the resected lesion showed a granulomatous lesion with central necrosis containing up to 35 transverse sections of a nematode, ranging 30-80 micro m in diameter. Thin (1.5-5 micro m) cuticle with transverse striations surrounded polymyarian and muscle bundles occupied a sixth of both sides of outer body cavity. Central portion of the body cavity was occupied with an intestine-like tubular structure and a larger reproductive tube. These microscopic findings were consistent with degenerated Dirofilaria immitis. Antibody test by enzyme-linked immunosorbent assay for patient serum reacted positively against adult D. immitis antigen.