Enterobius vermicularis worm granuloma mimicking like a pseudo tumor in the anal canal: An unusual clinical presentation
A 63-year old male from a rural area came to the surgical OPD with a polypoidal mass in the anal region. The mass was gradually increasing in size for past 20 years. He gave the complaint of pain and intense itching over the mass. On examination, the growth was from the anal wall, with skin covered and firmness in consistency measuring about 4 × 3 cm [Figures and ]. All the basic investigations done were within normal limits except a slight increase in the eosinophil count. Stool examination was negative for any worm or its ova. A differential diagnosis of squamous papilloma, fibroma, and foreign body granuloma were considered. Patient was admitted into the hospital and mass from the anal region was excised completely. Lateral sphincterotomy and Balal's stitch was done. Then the specimen was sent to the department of pathology where it was examined and processed.\nTo our surprise, histopathologic examination of the skin-covered lesion revealed the fragments of dead E. vermicularis worms surrounded by granulomatous reaction composed of epithelioid macrophages, foreign body type of giant cells and lymphocytes [Figures and ]. The granuloma was of the noncaseating type. Sections also showed stacks of pinworm eggs which are D-shaped with double contoured hyalinized shell. Eggs are also surrounded by many large foreign body-type giant cells and granulomas [Figures and ]. Thus, the deposition of eggs by the female gravid worm in the anal wall penetrating through the breaches elicited a severe foreign body type of granulomatous reaction. In the end, the anal canal growth turned out to be a “E. vermicularis worm granuloma with eggs.” This rare interesting case is presented here to stress the fact that worm granuloma can mimic a pseudo tumor in the anal region if untreated for a longer duration.