Dirofilaria in the abdominal cavity of a man in Japan.

A case of human dirofilariasis of the abdominal cavity is reported from Japan. The patient, a 74-year-old man, died of liver cancer; postmortem examination revealed a granulomatous mass on the mesentery. In histologic sections there were cross-sections of a mature female nematode identified as a Dirofilaria. The cuticle had a smooth surface and consisted of four distinct layers. The inner cuticular layer had internal lateral longitudinal ridges, and the musculature of the body wall was of the high polymyarian type. On the basis of morphology of the worm, it is suggested that this may represent the first human case of Dirofilaria immitis occurring in the abdominal cavity.