S965 Document heading 2012 by the Asian Pacific Journal of Tropical Disease. All rights reserved. Acute suppurative appendicitis with Blastocystis hominis Poppy M Lintong 1* , Maria Kr Sambuaga 1 , Eddy H Tambajong 2 1 Department of Anatomical Pathology, Universitas Sam Ratulangi Faculty of Medicine, Manado, North Sulawesi, Indonesia 2 Kanaka Clinical Laboratory, Manado, North Sulawesi, Indonesia Asian Pacific Journal of Tropical Disease (2012)S965-S968 Asian Pacific Journal of Tropical Disease journal homepage:www.elsevier.com/locate/apjtd *Corresponding author: Poppy M. Lintong, Department of Anatomical Pathology, Universitas Sam Ratulangi Faculty of Medicine, Manado, North Sulawesi, Indonesia. Tel: (+62) 08124401384/ 0431 834733 E-mail: magda_plin@yahoo.com 襃 1. Introduction Blastocystis hominis (B. hominis) is an anaerobic protozoan parasite [1,2] . In 1991, Zierdt identified the parasite as a sporozoa that causes blastocystosis ( Zierdt-Garavelli Disease) [1] in human. B. hominis was firstly reported by Alexeieff in 1911, followed by Brumpt in 1912 [2] . The parasite not only inhabits in human but also in several animals such as monkeys, apes, pigs, and maybe hamsters, reptiles, cockroaches, rats and other animals [2] . Vacuolated-form of B. hominis has been proven to be found in home rats’ feces [3] . On the other hand, the parasite is rarely found in both dogs and cats [4] . B. hominis is predominantly found in the tropical area. The parasite is mostly found within soldiers who come home from battle fields or among travelers [2] . In a routine examination performed to 932 immigrants in Taiwan’ s Eastern Sea, it is reported that 188 people (20.2%) of them had been infected by B. hominis. Such prevalence, compared with immigrants who come from Southeast countries such as Indonesia, Vietnam, and Philippines (26.4%, 20.6% and 19.3%, respectively) is higher than those from China (7.6%) [5] . The epidemiology of B. hominis in the United States had been reported to be found in 48 states and Columbia between 2002 and 2004. The annual prevalence of the parasite shows downward trend, from 23% in 2002 to 11% in 2004. Infection of the parasite is higher within September and October months than other periods, particularly in the coastal countries. Women are infected twice than men, especially between 40 and 49 year-old ages [6] . In an epidemiologic study performed in Canada, the average age of incidence of the populace who are infected by B. hominis is 37 years old, 55% of them are women [7] . The pathogenesis of B. hominis remains uncertain [1] . There is a controversy whether the parasite is commensal or pathogen [2,9] . Some textbooks describe that B. hominis is a low pathogen-protozoa and only induces intestinal disease within great amount [8] . Some expertise show that there is a negative correlation between the subsistence of B. hominis with diarrheal symptoms, which have been reported to increase, especially for patients with immunocompromise disease, travelers or tourists, homosexuals, and the abandoned children [9] . As a protozoan agent, B. hominis plays role and has pathogenic potency to provoke diarrheal ARTICLE INFO ABSTRACT Article history: Received 15 September 2012 Received in revised form 27 September 2012 Accepted 11 November 2012 Available online 28 December 2012 Keywords: Blastocystis hominis Acute suppurative appendicitis Blastocystis hominis (B. hominis) is an anaerobic protozoan parasite, which lives in human and animal’s intestines. It is commonly found in the tropical area. The parasite is low pathogen and its infection causes gastrointestinal disease with diarrhea symptom as reported from many studies. B. hominis is rarely seen in tissue section. The clinical diagnoses are usually confirmed with the microscopic examination of the stool, which can directly detect the parasite through trichrom stain and Kinyoun acid fast technique. We reported a case of 52 years old man with abdominal pain and suspected as perforated appendicitis and tumor of appendix as the differential diagnosis. The macroscopic features of the appendix mass were 7 cm in length and 1.5-2.5 cm in diameter. The cut section showed a widening of the appendix lumen, and the distal part filled with a gelatinous mass. The microscopic examination with HE stain showed the infiltration of PMN inflammatory cells in the muscle layer of the appendix and foci of a number of round structures in the sub mucosal layer known as B. hominis. Some authors reported results from the endoscopy and biopsy examinations that B. hominis does not infiltrate in the intestinal mucosa; nevertheless, in this case we found the infiltration of the parasite towards the mucosal and sub mucosal layers of the appendix. Contents lists available at ScienceDirect