HUMAN GNATHOSTOMIASIS IN MEXICO

Case 1 A 31-year-old man from Acapulco, Guerrero, in the southwest of Mexico, was seen in March 1994 for evaluation of a I-month history of intermittent migratory subcutaneous swellings on the left scapula, nec k, upper lip, and chin. The edema was painful and nonpruritic, with an oval shape of approximately 5-10 cm in diameter. After 2 days of a co urse of albendazole, 400 mg three consecutive oral doses, one every 12 h, the patient developed a creeping eruption that started on the left side and ended on the right side of the anterior neck. He practiced t he custom of eating a very popular Mexican delicacy, ''ceviche,'' made with raw fish cut into small pieces and mixed with different sauces a nd lime juice. On physical examination, there was a erythematous and i nfiltrated serpiginous linear lesion on the neck, 5 cm by 3 mm in size (Fig. 1). Laboratory studies of peripheral blood revealed a white blo od cell (WBC) count of 10,000/mm(3) with 39% eosinophils. A specimen f or biopsy was carefully taken, with a surgical knife, from the end of the creeping eruption, the lesion disappeared 1 week later leaving a l inear pigmentation. Histologic examination of the sections stained wit h hematoxylin and eosin showed, in the reticular dermis, longitudinal and transverse sections of a worm located within an area of necrosis a nd surrounded by an intense infiltrate of eosinophils (Fig. 2a). Cutan eous appendages in the immediate neighbourhood of the necrosis area we re seen to be surrounded by a dense inflammatory reaction composed of lymphocytes, histiocytes, and some eosinophils. The worm exhibited thr ee distinctive structures: at the anterior end, the cephalic bulb, in the mid-portion, the esophagus, and at the posterior end, the intestin e. The cephalic bulb, over one lateral side, was provided with four cu ticular spines. The circumference of the intestine was composed of 21- 24 columnar cells with six nuclei (average 3 mu m in diameter), and on e quadrant of the muscular layer consisted of 11-13 muscle cells (Fig, 2b). These morphological features, according to Japanese descriptions , are consistent with those of Gnathostoma spinigerum.(1) Case 2 A spe cimen for biopsy with a clinical diagnosis of gnathostomiasis was mail ed from Tepic, Nayarit, in the northwest of Mexico, to our dermatopath ology laboratory. The data accompanying the specimen mentioned that th e piece of tissue had been taken from an edematous and erythematous si nus cord, over a patch of 6x4 cm in diameter, localized on one buttock of a 25-year-old Mexican woman who practiced the custom of eating ''c eviche;'' no treatment had been given to the patient. Externally, the tissue presented one dark brown cylindrical ''U''-shaped organism meas uring 9 mm in length and 1 mm in breadth, localized on the center of t he surface of the specimen. The minute organism was dissected and scan ned using electron microscopy (Fig. 3a). Histologic examination of the specimen revealed a superficial cavity left by the removal of the wor m. The cavity was bounded on both sides by epidermis and its floor con tained slightly necrotic dermis with a diffuse inflammatory infiltrate composed of eosinophils and some neutrophils. Blood vessels were surr ounded by edema and a sparse infiltrate of lymphoid cells (Fig. 3b).