Echinococcosis of the liver and lungs

Echinococcosis Analysis

of the Liver and Lungs of Nineteen

Cases

N. FREDERICKHICKEN, M.D., A. JAMES MCALLISTER, M.D., JOHN H. AND FRANK MADSEN, M.D., Salt Lake City, Utah

were confirmed by operative intervention. (Table I.) In only one instance was the disease contracted outside of Utah. It seems, therefore, that echinococcosis is becoming more common in its distribution, and we must be alert if the spread of this infestation is to be controlled. This is particularly true now that tourists and sportsmen travel extensively in the endemic areas of the Eskimo and Northern Indians.

From the Surgical Department, University of Utah College of Medicine, and Latter-Day Saints Hospital, Salt Lake City, Utah.

in man is an indiscriminate E CHINOCOCCOSIS disease, extending from the arctic to the tropics. It shows no ethnologic affinities and has no regard for age or sex. This statement seems contrary to information found in the text, “Gastroenterology” [I], wherein hydatid disease is considered a rarity on the North American continent since only 652 cases had been reported between 1811 and 1946. These authorities estimated that only three to five new cases of hydatid disease would develop in the United States each year. Recent surveys by the public health organizations of Canada and the United States found echinococcosis prevalent throughout this continent. Wolfgang and Poole [Z] examined 2,023 Indians and Eskimos residing in Western Canada and obtained positive Casoni reactions in 31 per cent of those tested. Cameron [3] reported that 10 per cent of the Indian population of British Columbia and 40 per cent of those in the Yukon district harbored or had been infected by this parasite, and he estimated that fifty operations were performed each year in Canada for hydatid disease. Katz and Pan [4] discussed seventy-four cases of echinococcosis treated at the Massachusetts General Hospital. Judd [5] reported ninety cases at the Mayo Clinic, many of which had been contracted in foreign countries. Outbreaks of hydatid disease have been reported from Minnesota [6], Virginia [7], Tennessee [4], and New Jersey [7]. In the immediate environs of Salt Lake City, where the disease is endemic, nineteen cases have been reported, all of which Vol.

112.December

1966

CARLQUIST, ~I.D.,

ETIOLOGYAND CHARACTERISTICS Hydatid disease is caused by the larval stages of two tapeworms : Echinococcus granulosus (Batsch, 1776) and Echinococcus multilocularis (Leuckart, 1863 and renamed by Klem as Echinococcus alveolaris). While both varieties affect man, this discussion is concerned only with E. granulosus, as the life cycle of this parasite involves two distinct hosts: a definite or final host which harbors the adult tapeworm and an intermediate host which supports only the larval development. The adult tapeworm lives attached to villi of the small intestines of dogs, wolves, foxes, and sometimes the common house cat. The larval phase affects sheep, deer, caribou, and man. All intermediate hosts contract the disease by ingesting the ova of the tapeworm which has been excreted in the feces of infested carnivor. The domestic dog plays an important role in the transmission of human hydatidosis. Surveys indicate that 25 per cent of Eskimo dogs carry this parasite. When the eggs escape in the canine feces, they contaminate soil, vegetation, and drinking water. Children playing and women working outdoors ingest dust and dirt carrying the minute ova. Fruits, berries, vegetables, and drinking water provide an excellent 823

824

Hicken,

McAllister,

Carlquist,

and Madsen

TABLE I ECHINOCOCCIC CYSTSOF THE LIVER AND LUNGSIN NINETEENPATIENTS

Age (w.)

and Sex of Patients 18, 61, 26, 50, 48, 18, 67, 4, 10, 18, 19, 14,

F F M F M F M F M F M M

9, 22, 13, 30, 5, 4, 55,

F M F F M F M

-Location Liver

Left Right Right Right Right Right Left Right

of CystsLungs

-Drainage-Liver Lungs

Left

Right

--Lobectomics----. Liver Lungs

Left Right Right Right Right

Left

Right

500 cc. Right, lower Left, lower Left, lower Left, upper Right, many Right, multiple Right Right Right

Right

Right Left Left Left Yes Right Right Right Right Yes

Right

method of mechanical transference. Flies often carry the ova from canine feces to food, and the habit of petting the infested dog, as in our cases, provides a direct line of transmission. The adult tapeworm is small, measuring 2 to 4 mm. in length. Sexual maturity is reached in about six weeks at which time ova are liberated into the intestinal lumen, thus contaminating the excreted feces. When the ova are ingested by a suitable intermediate host, such as man, the gastric juices digest the outer protective covering of the egg, liberating the larva which then migrates through the intestinal wall and enters the portal vein and mesenteric lymphatics. As they pass through the liver, many larvae nidate within the small portal venules. Cameron [3] estimated “that of 100 hexacants reaching the liver, at least 70 would remain in this organ, while others migrate to the lungs, bones, brain, heart, kidneys, and eyes.” Although the mononuclear leukocytes attack and destroy many embryos, some do survive. By the end of the third week the young cyst will have attained a diameter of 250 ~1,and the surrounding tissues of the host will exhibit definite inflammatory reactions. However, it requires five months for the cyst to develop its morphologic characteristics, consisting of an outer protective capsule, which becomes hyalinized, and an inner germinative membrane,

Right, middle

Results

Well Well Well Well Well Calcified cyst Died of heart disease Recurrence Well Well Well Well Casoni test, negative reaction Well Well Well Well Casoni test, negative reaction Casoni test, positive reaction

which produces brood capsules and daughter cysts. As the brood capsules develop, some become detached and float in the cystic fluid, causing a “milky” discoloration and producing a granular sensation to touch which has aptly been described as “hydatid sand.” As the cyst enlarges through accumulation of cellular products and fluid, it exerts constant but ever increasing pressure on the containing tissues of the host. Simple unilocular cysts have been known to contain 12 L. of fluid. Not all hydatid cysts follow this pattern of growth. Some never form brood capsules, others become inactivated by bacterial contamination, and a few become confined by a dense calcified capsule which precludes their growth and expansion. Occasionally a cyst will produce brood capsules but no scolices and is therefore called an acephalocyst. If the confining capsule of the mother cyst is broken or ruptures, the liberated brood capsules attach themselves to contiguous organs and form daughter cysts. The cysts of E. granulosus never infiltrate or invade the tissues of the host and hence exist as a foreign body. Its morphologic characteristics are largely determined by the resistance offered by the involved organ. In the soft parenchymatous tissues of the lungs, the cyst expands rapidly and may become very large. The firm American

Journal of Surgery

Echinococcosis

of Liver and Lungs

texture of the liver, on the other hand, exerts a definite restraining influence on the expansion of the cyst; hence, they remain rather small. In bones, the cysts follow the longitudinal canals and, because they cannot expand, assume bizarre configurations. CLINICAL

FEATURES

Clinical manifestations of hepatic cysts are dependent on their size, location, number, and the presence or absence of complicating changes. A simple hydatid cyst of the liver is painless and asymptomatic unless it exerts pressure on adjacent organs, When the cyst becomes large, the patient may experience a sensation of “weight” and heaviness within the abdomen, which is aggravated by changes of position. Nausea and vomiting may result from occlusion causing pressure on the stomach or duodenum. Jaundice occurs only when the major bile ducts have become occluded. With palpation no abnormalities may be detected unless the tumor is situated on the margins of the liver or has attained unusual size. The cyst is smooth, firm, and nontender. The expanding cyst may elevate the diaphragm or extend below the costal margins. As previously mentioned, these hepatic cysts have a tendency to rupture, thereby liberating their liquid contents into the peritoneal cavity, lymphatics, and blood vessels. Such complications may produce severe anaphylactic reactions characterized by syncope, sweating, hypotension, and eosinophilia. The formation of daughter cysts within the peritoneal cavity gives rise to large nodular masses which may be mistaken for metastatic malignant growths. Interestingly, in 61 per cent of our patients the presenting complaints originated in the pulmonary system even though the primary focus was perhaps within the liver. If the cysts were located in the periphery of the lungs, which is usually the case, respiratory pains and dyspnea were common findings. Parabronchial cysts often interfered with respiration by compressing the larger bronchi. Occasionally a large cyst would exert so much pressure that it eroded into an adjacent bronchus, and in a violent paroxysm of coughing the entire cystic mass would be expectorated. In pulmonary hydatidosis the physical signs are striking but not pathognomonic. The side of the chest containing the cyst appears to bulge and, on actual measurement, will be Vol. 112. December I!.‘66

825

larger than its counterpart. Percussion elicits an area of dullness which often permits the spherical contour of the cyst to be outlined accurately. If the pericyst is located in the lower lobe of the right lung, it becomes attached to the diaphragm and may be mistaken for an enlarged liver or a subphrenic abscess. The breath sounds over the tumor are diminished and often bronchial in nature, thus suggesting consolidation or neoplastic infiltration. Large cysts may displace the heart, thereby producing dysfunctions of the circulatory system. PATHOLOGIC

VARIANTS

During its evolutionary development the hydatid cyst may undergo pathologic changes which modify the clinical symptoms. Dew [8] believes the most common complication is erosion of the cyst into the bile duct, thus permitting implantations within the ductal system. Litchman [9] found that 35 per cent of hepatic cysts produce obstructive jaundice by this method. Walters, Ramsdell, and Engel [lo] removed a recurrent hydatid cyst which was obstructing the choledochus. Hankins [ll ] believes the small occult lacerations often form patent communications between the cysts and bile ducts, thereby producing intrahepatic abscesses. Dagher and Hovnanian [12] suggest that the term, intrabiliary rupture, should be reserved for those cases in which definite communication between the cysts and biliary system can be demonstrated. Hematogenic infection of an intact pericyst occasionally results in septic abscess. Deve [13] insists that hepatic cysts rupture more frequently into the peritoneal cavity than into the biliary system. He found that in the univesicular variety entire cysts may be extruded and through implantation involve other visceral organs. In the multivesicular types the small vesical often ruptures, liberating the hydatid fluid, brood capsules, and scolices into the abdominal cavity. If the ruptured cysts communicate with the bile ducts, as they often do, seepage of bile may produce a chemical peritonitis. Hankins, on the other hand, believes that intraperitoneal rupture of the cysts is not always a massive phenomenon but rather a slow leak through small apertures in the wall of the cyst. These small lacerations often heal, but the escaping scolices spread the disease to other abdominal organs, thus forming metastatic hydatidosis.

826

Hicken, McAllister, Carlquist, and Madsen

Pericysts near the gallbladder or porta hepatis may involve the stomach or duodenum. We have observed one patient in whom such a cyst so effectively compressed the duodenum as to obstruct the stomach. According to Katz and Pan [4] seventeen cases of hydatid cysts of the spleen had been reported in the United States from 1822 to 1956. Hankins [11] described hepatic cysts which became implanted on the spleen only to rupture into the colon, Hydatid cysts growing in the head of the pancreas have been known to obstruct the common bile duct. It is understandable how attention would be focussed on the intestinal component rather than on the symptoms produced by the primary hepatic cyst. If the hepatic cysts are located in the dome of the right or left lobes of the liver, they often become adherent to the diaphragm and through pressure, necrosis, and inflammation involve the lower lobes of the contiguous lung. The formation of patulous hepatobronchial fistulas may permit the expectoration of bile and contents of the cysts. The presence of intervening infection often produces localized areas of empyema, consolidation, and pressure atelectasis of adjacent parenchymatous tissues. The pulmonary hydatid disease in eleven of our patients compelled them to seek assistance. (Table I.) It is generally agreed that hydatid infestation does not produce symptoms until the victim reaches the mid-span of life; yet, in this series 72 per cent were under twenty years of age. LABORATORY

TESTS

The Casoni test is performed by intradermal injection of 0.3 cc. of antigen which is usually obtained from infected sheep. When the reaction is positive, the wheal reaches its maximal size of 4 to 5 cm. in ten to twenty minutes and is surrounded by a definite erythematous flare. Katz and Pan [4] found the test dependable in 54 to 92 per cent of cases while Litchman [9] recorded an accuracy of only 56 per cent. The Casoni reaction is very sensitive and may remain positive years after removal of the cyst or after it has ceased to be viable. A negative reaction, therefore, is a good exclusion procedure. It must be remembered, however, that positive flares occur with urticaria, hayfever, angioneurotic edema, asthma, and infestations with other worms. There are two serologic tests, the hemagglu-

tination and the betonite flocculation reaction, which will give positive results in those patients who are actively producing and absorbing the hydatid antigen. A negative reaction does not exclude the presence of echinococcic disease, for a cyst may be calcified so that none of the antigen can be absorbed or the cyst may be quiescent and not produce the antigen. In either event the positive reactions will not be elicited. These immunologic tests are very accurate in determining recurrence or reactivation of the infestation. Roentgenography furnishes direct and indirect evidence of hepatic hydatid disease [14]. If the cyst is large, it alters the size, shape, and contour of the liver. Usually the right diaphragm will be pushed upward and exhibit impairment in excursion during respiration. Solitary calcified areas within the hepatic parenchyma should always arouse suspicion of echinococcic disease, requiring proper laboratory evaluation to differentiate hydatid cysts from calcified hemangiomas and intrahepatic abscesses. Gilsanz, Gallego, and Calle-Yuste [15] have been able to localize and diagnose eleven cases of hydatid cysts by means of splenoportograms. The expanding cysts distort, displace, and compress the regional portal veins while the area occupied by the cyst is avascular. Since any benign cysts will produce similar roentgenologic patterns, confirmatory laboratory studies are essential. Scanograms of the liver with rose bengal isotopes have been very effective in localizing intrahepatic cysts. The cystic area, being practically devoid of blood and having no functioning liver cells, will not absorb the isotope; hence, the affected areas can be clearly demonstrated. A presumptive diagnosis of pulmonary hydatid disease can usually be made by x-ray examinations. Within the lung fields a typical cyst appears as a well defined spherical mass ; if the cyst has eroded into a bronchus, there will be a definite fluid level because of the admixture of air and fluid. Contrast bronchography often demonstrates pressure displacement of the larger bronchi. If the cystic shadow is contiguous with the diaphragm, hepatic involvement is probable. Roentgenologic differentiation of hydatid cysts from benign tumors, such as dermoid cysts, intrathoracic goiters, or aneurysms, is sometimes most difficult; hence, American

Journal of Surgery

827

Echinococcosis of Liver and Lungs definite immunologic evaluation is also necessary. TREATMENT

As the use of chemotherapy and antibiotic agents in the treatment of echinococcosis has been disappointing, surgical therapy offers the best prognosis. Whenever possible, the parasitic cyst should be completely excised ; if this is impossible, it should be completely destroyed. Selection of the definitive surgical procedure depends on the specific organ involved, the location, size, and number of cysts, and the presence or absence of complicating changes. ASPIRATION

AND

CHEMICAL

STERILIZATION

Simple evacuation of the cystic cavity by aspiration and sterilization of its contents by instillation of suitable scolicides has had wide acceptance. The scolicides destroy the larva, brood capsules, and germinal epithelium through a process of dessication ; however, as chemical sterilization is not always complete, many cysts so treated continue to propagate their larval infestation. Formalin is not an entirelv satisfactory chemical scolicide; hence, investigative studies have been made in an effort to obtain more reliable agents. Meymerian et al. [16], after studying thirty-eight chemical substances, conclude that, “in terms of maximum effective dilution, shortest effective time, and least toxicity, hydrogen peroxide, cetrimide, iodine, octoglycine-dihydropentiodide, sodium hypochlorite, glycerin, and formalin were the most useful scolicides, in the order given.” Hankins 111] reported two deaths which he believed were attributable to reactions to formalin. One patient was a young woman who died of cardiac arrest immediately after the hepatic cysts were filled with formalin. The other was a young man who died from fulminating peritonitis when some cf the formalin was accidentally spilled within the peritoneal cavity. We agree with Hankins [ll ] who believes that a 96 per cent alcohol solution is a very effective scolicide and much safer than formalin. Evacuation consists of exposing the pericyst, protecting the surrounding tissues with gauze packs, and carefully aspirating its fluid contents. The cystic cavity is completely filled with a suitable chemical agent which is left in situ for ten minutes and then aspirated. It is Vol. 112. December 1966

hoped that the sterile cyst will collapse and become obliterated by fibrosis, but unfortunately this is not always accomplished. When the cyst is embedded in the firm parenchymatous tissues of the liver or if its walls are hyalinized or calcified, it cannot collapse and hence remains a potential cavity which invariably becomes infected. This method of treatment should be used only in complicated cases. INCISION

AND

DRAINAGE

: MARSUPIALIZATION

Marsupialization is particularly useful when the cysts are infected or so situated that their complete removal is impossible. After the cystic mass is exposed, its contents are siphoned into a vacuum bottle and the cavity is completely filled with a 96 per cent alcohol solution for ten minutes and then aspirated. The wall of the cyst is carefully opened and its adventitial layer is swabbed with a 96 per cent alcohol or ether solution. This dessicating procedure may permit removal of the adventitial lining by means of blunt dissection. No attempt should be made to remove the outer fibrous wall since this protects the surrounding tissues of the host. A rubber drain is inserted into the cystic cavity and anchored by sutures to maintain accurate position. The drains are left in situ until the residual space is obliterated by fibrosis or regenerated tissues from the liver. Prolonged drainage is necessary, particularly if the cyst was infected. One variation in simple marsupialization consists of obliterating the cystic space by approximating the walls of the cysts and holding them in firm apposition with sutures. While this procedure is often successful when dealing with pulmonary hydatid cysts, it is not so effective when applied to hepatic cysts. If the walls of the cyst are rigid from fibrosis or calcification, they cannot be approximated by suturing. Likewise, it is impossible to obliterate an intrahepatic hydatid cavity by capsulorrhaphy as the surrounding parenchymal tissues offer too much resistance. When this is attempted, the sutures often enter the hepatic parenchyma severing bile ducts and thus permitting leakage of bile with resulting bile peritonitis. Hankins [ll ] believes it unnecessary and unwise to attempt to obliterate the cystic cavity. Such has been our experience. Jidejian [17] does not attempt to obliterate the cyst but rather fills it with isotonic saline

828

Hicken, McAllister,

FIG. 1. Hepatic cyst filled with 1,250 cc. of Hypaque solution. It occupied the caudate, quadrate, and left lateral segments of liver.

solution and completely closes the incision in the cyst wall. He reports that one of ten cases so treated became infected. We prefer simple drainage to this procedure. PARTIAL

RESECTION

AND

LOBECTOMIES

The ideal surgical treatment for hepatic hydatid disease is complete removal of the pericyst and adjacent tissues of the host. Pack and Molander [18] point out that this often requires resection of the hepatic lobe in which the cyst develops. Bourgeon and Guntz [19] believe this to be the preferred treatment. We applied this technic to a 5 cm. cyst occupying the right lobe of the liver and gallbladder area. The entire cyst, gallbladder, and one fourth of the right lobe of the liver were resected en masse. The operative area was drained externally and a satisfactory recovery ensued. Whenever a single large cyst or many daughter cysts occupy an entire lobe of the liver, the best chance for recovery consists of complete removal of the diseased portion of the liver. Hepatic lobectomies can be safely performed, as evidenced by the following case. CASE REPORT

The patient, an eighteen year old girl, was born in Utah and reared in a small rural community where sheep raising was one of the main industries. She was fond of dogs and cats and always had several as pets. Her first symptoms consisted of a persistent

Carlquist, and Madsen cough accompanied by pleuritic pains in the left upper part of the chest. Intensive penicillin therapy resulted in temporary remission of symptoms. Nine months later she had a brisk hemoptysis and was admitted to the hospital. X-ray studies demonstrated an increased density of the left upper lobe of the lung, with elevation of the left diaphragm. Bronchoscopic examination failed to disclose any neoplastic involvement, and bronchial washings were negative for malignant cells or parasitic organisms. A Casoni skin test was positive for echinococcosis. In the belief that this was an infected pulmonary cyst, exploratory thoracotomy was performed. The upper lobe of the left lung was partially atelectatic and the upper left bronchus was partially occluded by a hard, firm, inflammatory mass. Further exploration revealed the left diaphragm to be elevated by extensive tumefaction in the left lobe of the liver. Needle aspiration of the mass recovered fluid containing scolices and brood capsules. The diaphragm was closed and the upper lobe of the left lung was removed. The drainage from the hydatid cyst contained bile, indicating a patulous communication with the bile ducts. The drainage tubes were injected with radiopaque material (Hypaque@), and a large cystic mass was visualized measuring 11 by 17 cm. and occupying the left lobe of the liver. (Fig. 1.) Isotope scans demonstrated a normal right hepatic lobe, but the quadrate, caudate, and left lateral lobes could not be visualized, indicating complete loss of function. Abdominal explorations revealed that the hepatic cyst had displaced the spleen downwards, elevated the diaphragm, and pushed the stomach and duodenum into the right upper abdominal quadrant. An operative cholangiogram outlined a normal ductal system within the right lobe, but none of the contrast media entered the left hepatic radicals. The liver parenchyma surrounding the cysts was thick, fibrotic, and avascular, indicating complete thrombosis of the left hepatic artery and vein. The multilocular cyst not only occupied the left lateral lobe of the liver but also extended into the quadrate and caudate lobes. By following the central fissure of the liver, the entire left lobe of the liver and the enclosed cyst were removed intact. Bleeding was no problem because of thrombotic occlusion of the left hepatic artery and left portal vein. The bile ducts and blood vessels were ligated as they appeared on the cut surface of the liver. No attempt was made to cover the denuded surface of the liver with omental tissue or hemostatic agents. Two large Penrose drains were placed against the cut surface of the liver. A decompression tube was anchored into the fundus of the gallbladder to evacuate the bile from the right lobe of the liver, so as to minimize seepage of bile from the severed bile ducts on the cut American

Jouvnal

of Surnery

Echinococcosis

of Liver and Lungs

surface of the liver. The patient made a rapid recovery and was discharged from the hospital on the twenty-second postoperative day. The drainage tubes were all removed three weeks later. Follow-up studies nine months later demonstrated normal lungs. Gastrointestinal roentgenograms revealed that the stomach was still in the right upper quadrant, as in the preoperative studies. Isotope scanograms of the liver outlined a normal right lobe but there had been no effort toward regeneration of the left lobe. (Fig. 2.j The patient continued her college work, which included being a cheerleader. Four years later the Casoni reactions were positive, but the other immunologic tests all gave negative reactions. She was married and is the mother of two healthy children. COMMENTS

There has been some controversy concerning the management of the exposed surface of the liver after the diseased segments have been removed. One school of thought believes the freshly denuded surface of the liver should be protected with hemostatic substances such as Oxycel”, Ivalon’, or Gelfoam@, to minimize the seepage of bile and blood. Other workers maintain that adequate drainage of the operative site with Penrose drains is all that is required. Hicken, McAllister, and Nilsson [ZO], in an experimental study with dogs, found these substances ineffectual as hemostatic agents since blood and bile collected between them and the liver, forming accumulated debris which invariably became infected. Furthermore, the liver does not accept these “foreign” substances but rather extrudes them into the peritoneal cavity where they promote intense granulomatous reactions. In addition, these substances, particularly Ivalon, were absorbed so slowly that the period of drainage was lengthened. Because of these studies, we prefer to use simple drainage of the operative site, hoping to evacuate all seepage material externally. Clinical experience with patients confirms the feasibility of this plan.

FIG. 2. Operative cholangiogram outlines normal ductal system of right lobe of liver. The caudate, quadrate, and left lobes have been removed. RAS, right anterior segment ducts; RF’S, right posterior segment ducts; GB, gallbladder; CBD, common bile duct.

direct methods of transmission. The lungs were involved in twelve cases, and liver in nine, and both the lungs and liver in two instances. Both sexes were about equally affected, and ten patients were under twenty years of age. In twelve cases of pulmonary hydatidosis, either lobectomies or pneumectomies proved to be effective methods of treatment. In hepatic diseases, aspiration, marsupialization, and lobectomies were all tried. Experience teaches that hepatic lobectomy with complete removal of the hydatid cysts is the preferred modality. Follow-up studies have demonstrated only one recurrence to date. The increasing incidence of hydatidosis should be of great concern to both physicians and public health officials. REFERENCES

SUMMARY

Nineteen cases of echinococcosis are presented with particular emphasis on epidemiology, clinical manifestations, and evaluation of various types of surgical treatment. Eighteen patients were inhabitants of Utah and contracted the disease in these confines. Intimate

contact

with sheep, dogs, and cats afforded

Vol. 112. lkcemher

1966

1. Boc~vs, H. L,. Gastroenterology, vol. 3, 1, 370. Philadelphia, 1946. W. B. Saunders Co. 2. WOLFGANG, R. W. and POOLE, J. B. Distribution of echinococcus disease in Northwestern Canada. Am. J. Trap. Xed., 5: 869, 1956. and diagnosis of 3. CAMERON, T. M. Incidence hydatid disease in Canada: Echinococcus granulosus var. Canadensis. Paresitologia, 2 : 381, 1960. 4. KATZ, A. M. and PAN, C. T. Echinococcic diswse in I’nitctl States. Am. J. Med.. 25: $59, 19%.

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Hicken, McAllister, Carlquist, and Madsen

5. JUDD, E. S. Surgical treatment for echinococcus cysts of liver. Proc. Staff Meet. Mayo Clin., 35: 58, 1960. 6. RILEY, W. A. Reservoirs of echinococcus in Minnesota. Minnesota M. J., 16: 744, 1933. 7. SCHILLER, E. L. Echinococcosis in North America.

Ann. Int. Med., 52:464, 1960. 8. DEW, H. R. Hydatid Disease:

Its Pathology, Diagnosis and Treatment, p. 420. Sidney, Australia, 1928. Medical Publishing Co. 9. LITCHMAN, S. S. Disease of the Liver, Gall Bladder and Bile Ducts, 3rd ed., vol. 2, p. 892. Philadelphia, 1953. Lea & Febiger. 10. WALTERS, W., RA~~SDELL, J. A., and ENGEL, S. Recurrent echinococcic cyst in common bile duct.

14. 15.

16.

17. 18.

Arch. Surg., 81: 768, 1960. 11. HANKINS, J, R. Management of complicated hepatic hydatid cysts. Ann. Surg., 158: 1020, 1963. 12. DAGHER, I. A. and HOVNANIAN, A. P. Intrabiliary rupture of hydatid cysts of the liver. Ann. Surg., 141: 263, 1955. 13. DEVE, F. L’ouverture des cystes hydatiques du foie

19.

20.

dans les voies biliaries. Norman&e mt!d., 1932. Quoted by Hankins, J. R. [11]. COLEMAN, P. Radiographs of hydatid disease. Radiography, 25: 193, 1959. GILSANZ, V., GALLEGO, M., and CALLE-YUSTE, P. Portal circulation in hydatid cysts of liver. Arch. Int. Med., 108: 540, 1961. MEYMERIAN, E., LUTTERMOSER, G. W., FRAHA, G. F., SCHWABE, C. W., and PRESCOTT, B. Host parasite relations in echinococcus. Surg. Gynec. 6 Obst.,117: 211, 1963. JIDEJIAN, Y. Collective review of hydatid disease. J. Internat. Coil. Surgeons. 28: 125, 195i. PACK, G. T. and MOLANDER, D. N. Hepatic lobectomy for recurrent echinococcic cysts of liver. Am. J. Gastroenterol., 33: 43, 1960. BOURCEON. R. and GUNTZ, M. The place of hepatectomy in treatment of hydatid cysts. Rev. Int. Hepato. 10: 1020, 1960. HICKEN, N. F., MCALLISTER, A. J., and NILSSON, J. Resection of entire left lobe of liver; intrahepatic abscessed, stones and foreign bodies. Am. J. Swg., 105: 278, 1963.

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