Radio-pathological diagnosis of hepatobiliary ascariasis: A rare entity.

Ascariasis is the commonest helminthic infection in humans, caused by the nematode Ascaris lumbricoides. The adult worms usually reside in the small intestine. Rarely, they migrate into the bile duct and pancreatic ducts, but involvement of the gall bladder and/or liver parenchyma is extremely rare. Here, we describe a case of a 32-year-old woman who presented with fever, anorexia, right upper quadrant pain and mild hepatomegaly. Ultrasonography revealed a liver abscess and a concurrent moving adult worm in the gall bladder. Fine-needle aspiration cytology (FNAC) from the liver abscess showed presence of fertilized eggs of Ascaris lumbricoides. A diagnosis of gall bladder and hepatic ascariasis was made. The patient responded well to conservative management. Ascaris-induced liver abscess with concurrent living adult worm in gall bladder has rarely been reported. Ultrasonography and FNAC are important diagnostic modalities for detection of such lesions. Conservative management appears to be the treatment of choice for hepatobiliary ascariasis.

Introduction

Ascariasis, caused by the nematode Ascaris lumbricoides, is the commonest helminthic infection among humans.[1] The infection spreads via the faeco-oral route and hence its prevalence is more in the tropical and subtropical developing countries, which are ravaged by the problems of poverty, overcrowding and poor sanitation. The adult worm originally resides in the small intestine but has the habit of migrating through natural orifices to the bile duct and pancreatic ducts. Involvement of the gall bladder is very rare, constituting only 2.1% of the total cases of biliary ascariasis.[2] Liver abscess caused by ascaris is also a very rare form of hepatobiliary ascariasis. We report a case for its unique and rare presentation and to emphasize the need for initiation of medical therapy rather than overzealous surgical approach as the first-line treatment in these cases.

Case Report

A 32-year-old female patient presented to the outpatient clinic with complaints of anorexia, fever and pain in the right hypochondrium. On examination, the patient was emaciated, anemic and icteric with mild tender hepatomegaly. Blood examination showed hemoglobin of 9.0 gm/dL with mildly microcytic, hypochromic red blood cells coupled with neutrophilic leucocytosis and eosinophilia. Liver function tests showed a total serum bilirubin of 2.4 mg/dL (normal, <1 mg/dL); aspartate serum transferases, 120 IU/mL (normal, 0-40 IU/L); alanine serum transferases, 88 IU/mL (normal, 0-43 IU/L); and alkaline phosphatase, 180 IU/L (normal, 37-147 IU/L). An abdominal ultrasound was done, which revealed hepatomegaly with a cystic space–occupying lesion of 3 cm diameter in the right lobe of liver just adjacent to the right kidney. The lesion was of heterogenous echotexture and had irregular margins. The gall bladder showed presence of a long, straight, tubular, non-shadowing, echogenic structure showing erratic, zigzag movements, suggestive of Ascaris lumbricoides. The biliary tree was mildly dilated, but no other worm could be visualized [Figure 1].

Figure 1

(a) Photograph of ultrasonogram showing liver abscess (arrow) adjacent to the right kidney (RK). (b) Photograph of ultrasonogram showing the roundworm (RW) within the gall bladder (GB) lumen

An ultrasound-guided fine-needle aspiration was done from the cystic structure of the liver with a 24-gauge needle fitted to a 10-mL syringe. The smears prepared from the aspirate were stained with hematoxylin and eosin stain, as well as May-Grünwald-Giemsa (MGG) stain.

The microscopic examination revealed presence of a large number of fertilized, decorticated eggs of Ascaris lumbricoides with the background showing mostly bile, scattered degenerated hepatocytes, neutrophils and Charcot-Leyden crystals [Figures 2 and 3]. A diagnosis of ascaris-induced liver abscess and gall bladder ascariasis was rendered. The patient was treated conservatively with oral antibiotics for 7 days and a dose of albendazole (400mg). The same dose of albendazole was repeated after 7 days. During this period, the stool was examined daily for a total of 14 days. The patient passed ascaris eggs daily during the first 8 days. Two adult worms were passed in stool on the 8th day; and one, on the 9th day. The stool was free from parasites and ascaris eggs for the next five days. A repeat ultrasound was done on the 10th day. There was no worm in the gall bladder or the biliary tract, the hepatic abscess resolved almost completely and the patient symptomatically improved.

Figure 2

Microphotograph showing fertilized, decorticated eggs of Ascaris lumbricoides(H and E, × 400). Inset showing one such egg in higher magnification (H and E, × 1000)

Figure 3

Microphotograph showing fertilized, decorticated eggs of Ascaris lumbricoides(thick, blue arrows) in a necrotic background (MGG, × 400). Inset (lower right) showing one such egg in higher magnification (MGG, × 1000). Inset (upper left) showing Charcot-Leyden crystals (black arrows) in a background of necrosis and acute inflammatory cells (MGG, × 400)

Discussion

Ascariasis is the commonest human helminthic infection,[1] particularly common in the developing countries suffering from poverty, poor sanitation and overcrowding. The roundworm, as it is commonly called, resides in the small intestine—most frequently in the jejunum and middle ileum. The adult worm, however, has a natural tendency to explore the natural body orifices and get into the hepatobiliary system or the pancreas, causing cholelithiasis, acute cholecystitis, choledocholithiasis, acute pancreatitis or ascending cholangitis.[34] Involvement of gall bladder is extremely rare, constituting 2.1% of the total cases of biliary ascariasis.[2] The rarity is possibly due to the narrowness and tortuosity of the cystic duct,[5] through which the worm cannot negotiate easily. Liver abscess due to ascariasis is indeed a rare, though a known entity, constituting about 1% of total cases of hepatobiliary ascariasis; however, the incidence may be higher in endemic areas.[6] Most of the cases have been diagnosed during surgery or autopsy, but reports on aspiration cytology are sparse. In our case, the patient had both a liver abscess containing ascaris eggs and gall bladder ascariasis. The liver abscess may have been caused by a gravid female worm which may have gone deep into the liver parenchyma through the bile duct, laid the eggs and subsequently died. The area might then have been infected to form an abscess. The background of the smears was composed of bile, which was a result of bile stasis, along with neutrophils and Charcot-Leyden crystals. Ultrasonography is an important non-invasive diagnostic modality for hepatobiliary ascariasis, and the appearance and movement of ascaris are characteristic.[7] Worms in the biliary tree are not easily killed by anti-helminthics as these drugs are poorly excreted in bile, and surgical interventions are often required. In our case, however, the patient fortunately responded well to conservative management with albendazole, with passage of adult worms in stool. The patient's condition improved on conservative treatment, emphasizing the fact that this appears to be the preferred first-line treatment for these types of cases.