Gnathostomiasis in a patient who frequently consumes sushi

A 45-year-old woman presented for evaluation of a solitary pruritic nodule on the abdomen that suddenly appeared 3 weeks before. She was healthy without a significant medical history, travel history, exposures, medications, or pets. She reported that she consumed sushi at least weekly in the city of San Francisco. A punch biopsy revealed a superficial and deep perivascular and interstitial infiltrates consisting of lymphocytes, plasma cells, and many eosinophils. Most notably, there was a parasite centered in the reticular dermis with prominent lateral chords, a well-developed muscular esophagus, and an intestine that contained a brush border and multinucleate cells. Evaluation of these histological sections by the Centers for Disease Control and Prevention determined the parasite to be a nematode of the genus Gnathostoma. The patient underwent a systemic work-up for gnathostomiasis, including imaging, and no other abnormalities were found. She completed a 3-week course of albendazole and has remained asymptomatic since the biopsy of her abdominal lesion. Although gnathostomiasis is often a systemic illness, this patient did well with apparently only localized cutaneous disease. Gnathostomiasis should be considered in patients who present with nonspecific papules and nodules, especially when there is a history of frequent consumption of raw fish.