Case reports
1992, The British Journal of Radiology, 65, 604-606
LANCET, 1975. Nomenclature of congenital limb deficiencies ROBINS, D. B., LADDA, R. L., THEIME, G. A., BOAL, D. K., EMANUEL, B. S. & ZACKAI, E. H., 1989. Prenatal detection of (editorial). Lancet, II, 117. Roberts-SC phocomelia syndrome—report of 2 sibs with MOORE, K. L., 1982. The Developing Embryo, 3rd edn (W. B. characteristic manifestations. American Journal of Medical Saunders, Philadelphia). Genetics, 32, 390-394. NORA, J. J. & NORA, A. H., 1974. Can the pill cause birth defects? (editorial). New England Journal of Medicine, 291, ROGALA, E. J., WYNNE-DAVIES, R., LITTLEJOHN, A. & GORMLEY, J., 1974. Congenital limb anomalies: frequency 731-732. and aetiological factors. Journal of Medical Genetics, 11, OERTEL, O., 1962. Amelia bei Zwillingen. Monatschrift 221-233. Kinderheilkunde, 11, 481-484. OHDO, S., MADOKORO, H., SONODA, T., TAKEI, M., YASUDA, H.
& MORI, N., 1987. Association of tetra-amelia ectodermal dysplasia hypoplastic lacrimal ducts and sacs opening towards the exterior peculiar face and developmental retardation. Journal of Medical Genetics, 24, 609-612.
ROMKE, C , FROSTER-ISKENIUS, U., HEYNE, K., HOHN, W., HOF, M., GRZEJSZCK, G., RAUSKOLB, R., REHDER, H. &
SCHWINGER, E., 1987. Roberts syndrome and SC phocomelia—a single genetic entity. Clinical Genetics, 31, 170-177.
PAULI, R. M. & GREENLAW, A., 1982. Limb deficiency and
VAN ALLEN, M. I., CURRY, C , WALDEN, C. E., GALLAGHER, L.
splenogonadal fusion. American Journal of Medical Genetics, 13, 81-90.
& PATTEN, R. M., 1987b. Limb body wall complex: II. Limb and spine defects. American Journal of Medical Genetics, 28, 549-565.
PAWLOWITZKI, I. H., CENANI, A. & FRISCHBIER, H. J., 1973.
Autosomal monosomy (45, XX, C —) in the human embryo with total amelia and further malformations. Clinical Genetics, 4, 193-202. RINDEZ, 1939. Uber doppelseitige aplasie freien oberen Gliedmasse (brachiale amelia). Zeitungen Geburtschrifte Gyndkologie, 118, 442-447.
VAN ALLEN, M. I., CURRY, C. & GALLAGHER, L., 1987a. Limb
reduction wall complex: I. Pathogenesis. American Journal of Medical Genetics, 28, 529-548. ZIMMER, Y., SOVA, M. Y., DIVON, M., PERY, M. & PERETZ,
B. A., 1985. Tetra-amelia with multiple malformations of one kindred. European Journal of Pediatrics, 144, 412-414.
Ultrasound demonstration of a leaking hydatid cyst of the liver causing "cyst within a cyst" appearance By B. Banerjee, FRCS, DMRD, FRCR, A. Rennison, BSc(Hons), DCRR and *Q. M. Haque, DMRD, FRCR Department of Diagnostic Radiology & Imaging, Tameside General Hospital, Ashton-Under-Lyne, Lancashire OL6 9RW and *Ormskirk District General Hospital, Wigan Road, Ormskirk, Lancashire L39 2AZ, UK
Based on a poster presented at the BMUS 23rd Annual Meeting in Bournemouth, on 10-12 December 1991 Keywords: Unilocular hydatid cyst, Simple liver cyst, endocyst, "Cyst within a cyst"
Echinococcal disease may affect any part of the body; the liver is the most frequently affected organ (75%) (Saidi, 1976). Although a cyst with internal septation or loculation is the classical ultrasound description of hydatid cyst of the liver, in reality unilocular cysts are more frequently encountered (Sciarrino et al, 1991). On ultrasound unilocular hydatid cysts are usually indistinguishable from innocent simple hepatic cysts, which are common incidental findings during ultrasound examination of the liver. Moreover, in a non-endemic area the index of suspicion is low and the possible diagnosis of hydatid disease may not be entertained when unilocular cysts are detected in the liver. On rare occasions, however, the thin internal membrane, the endocyst, of a unilocular hydatid cyst may separate spontaneously from the thick outer ectocyst, giving rise Address correspondence to Dr B. Banerjee.
604
to the appearance of a cyst with a membrane-like structure beneath its wall. Demonstration of the internal membrane is considered to be pathognomonic of hydatid disease (Beggs, 1983; Garcia et al, 1988) and allows a firm diagnosis of hydatid disease by ultrasound alone. We present a case to illustrate the above mechanism.
Case report A 42-year-old woman presented with dyspepsia and vague right upper quadrant discomfort and underwent ultrasound examination of the abdomen for suspected calculous disease of the gallbladder. Her past medical history was unremarkable and her whole blood count and urine analysis were normal. On ultrasound no calculus was detected in the gallbladder or bile ducts and the gallbladder appeared normal. A thin-walled unilocular echo-free cystic space of 2.7 cm diameter was noted in the right lobe of the liver (Fig. 1). This was diagnosed as a
The British Journal of Radiology, July 1992
Case reports
Figure 1. Longitudinal scan of the liver, demonstrating a unilocular cyst in the right lobe of the liver (arrowheads). There is no evidence of internal echo and there is distal enhancement. A normal gallbladder is seen (curved arrow). simple liver cyst and considered to be an innocent incidental finding. Several days later, the patient attended the Accident and Emergency Department with an acute exacerbation of her symptoms and a clinical diagnosis of acute cholecystitis was made. A repeat ultrasound examination, performed within a short time of her arrival, revealed no evidence of gallbladder disease, but there was a striking change in the appearance of the cystic lesion in the right lobe of the liver. There was now a membrane-like structure partially separated from the inner wall of the capsule of the cyst (Fig. 2) and, while scanning was still
Figure 3 caption and part (c) overleaf. in progress, the sonographer witnessed the complete separation of the internal membrane from the capsule of the cyst, producing a "cyst within a cyst" appearance (Fig. 3). During and after the completion of the separation of the internal membrane the patient did not experience any increased discomfort. A complement fixation test for hydatid disease was positive, confirming the diagnosis. The blood count and liver function tests were normal and on enquiry no definite association with endemic areas of hydatid disease was revealed. The patient was discharged from the hospital within a few days following improvement of her acute symptoms but some vague discomfort persisted. Figure 2. There is partial separation of the internal membrane, the endocyst (curved arrow), from the outer cyst wall, the ectocyst. Vol. 65, No. 775
Discussion
The ultrasound appearance of hydatid cysts of liver is varied. The diagnostic difficulty of "solid" forms of 605
Case reports
hydatid cyst is well documented (Garcia et al, 1988). Unilocular echo-free hydatid cysts may be indistinguishable from simple hepatic cysts by ultrasound. However, demonstration of an internal membrane in such a cyst is considered to be pathognomonic of hydatid; therefore, when serology is negative, demonstration of an internal membrane may be the only indicator of the true nature of the cyst. Detachment of the internal membrane is most likely due to a host defence mechanism or ageing of the parasite (Lewall & McCorkell, 1986). Some authors believe that the univesicular cyst represents the fully developed form of the parasite, and the subsequent stages after rupture of the cyst, namely separation of the internal membrane and formation of daughter cysts, are attempts at survival by the parasite (Barriga et al, 1983). This case illustrates that echinococcal disease should be considered in the differential diagnosis of every cyst in the liver, even though the patient may not have lived in an endemic area. Acknowledgment Thanks to Mr R. Biggs for the photography. References BARRIGA, P., CRUZ, F. V. & LATHROP, R., 1983. An ultrasono-
graphically solid, tumor-like appearance of echinococcal cysts in the liver. Journal of Ultrasound in Medicine 2 (3), 123-125. BEGGS, I., 1983. The radiological appearances of hydatid disease of the liver. Clinical Radiology, 34, 555-563. GARCIA, F. J., MARTI-BONMATI, L., MENOR, F., RODRIGUES, B.
& BALLESTA, A., 1988. Echogenic forms of hydatid cysts: sonographic diagnosis. Journal of Clinical Ultrasound, 16, 305-311. Figure 3. (a) Oblique sagittal view of the right lobe of the liver showing the intact wall of the hydatid cyst, (b) Partial separation of the internal membrane of the cyst (curved arrow) is noted at the beginning of the examination, (c) There is now complete separation of the internal membrane, giving rise to a "cyst within a cyst" appearance (arrowheads) while the ultrasound examination is still in progress.
LEWALL, D. B. & MCCORKELL, S. J.,
1986. Rupture of
echinococcal cysts. American Journal of Roentgenology, 146, 391-394. SAIDI, F., 1976. Surgery of Hydatid Disease (Saunders, Philadelphia), Ch. 3, pp. 31-155. SCIARRINO, E., VlRDONE, R., LOIACONO, O., FUSCO, G., RlCCA, T., COTTONE, M., MARINGHINI, A. & DELLA MONIA, A.,
1991. Ultrasound changes in abdominal echinococcosis treated with Albedozole. Journal of Clinical Ultrasound, 19, 143-148.
606
The British Journal of Radiology, July 1992
1992, The British Journal of Radiology, 65, 604-606
LANCET, 1975. Nomenclature of congenital limb deficiencies ROBINS, D. B., LADDA, R. L., THEIME, G. A., BOAL, D. K., EMANUEL, B. S. & ZACKAI, E. H., 1989. Prenatal detection of (editorial). Lancet, II, 117. Roberts-SC phocomelia syndrome—report of 2 sibs with MOORE, K. L., 1982. The Developing Embryo, 3rd edn (W. B. characteristic manifestations. American Journal of Medical Saunders, Philadelphia). Genetics, 32, 390-394. NORA, J. J. & NORA, A. H., 1974. Can the pill cause birth defects? (editorial). New England Journal of Medicine, 291, ROGALA, E. J., WYNNE-DAVIES, R., LITTLEJOHN, A. & GORMLEY, J., 1974. Congenital limb anomalies: frequency 731-732. and aetiological factors. Journal of Medical Genetics, 11, OERTEL, O., 1962. Amelia bei Zwillingen. Monatschrift 221-233. Kinderheilkunde, 11, 481-484. OHDO, S., MADOKORO, H., SONODA, T., TAKEI, M., YASUDA, H.
& MORI, N., 1987. Association of tetra-amelia ectodermal dysplasia hypoplastic lacrimal ducts and sacs opening towards the exterior peculiar face and developmental retardation. Journal of Medical Genetics, 24, 609-612.
ROMKE, C , FROSTER-ISKENIUS, U., HEYNE, K., HOHN, W., HOF, M., GRZEJSZCK, G., RAUSKOLB, R., REHDER, H. &
SCHWINGER, E., 1987. Roberts syndrome and SC phocomelia—a single genetic entity. Clinical Genetics, 31, 170-177.
PAULI, R. M. & GREENLAW, A., 1982. Limb deficiency and
VAN ALLEN, M. I., CURRY, C , WALDEN, C. E., GALLAGHER, L.
splenogonadal fusion. American Journal of Medical Genetics, 13, 81-90.
& PATTEN, R. M., 1987b. Limb body wall complex: II. Limb and spine defects. American Journal of Medical Genetics, 28, 549-565.
PAWLOWITZKI, I. H., CENANI, A. & FRISCHBIER, H. J., 1973.
Autosomal monosomy (45, XX, C —) in the human embryo with total amelia and further malformations. Clinical Genetics, 4, 193-202. RINDEZ, 1939. Uber doppelseitige aplasie freien oberen Gliedmasse (brachiale amelia). Zeitungen Geburtschrifte Gyndkologie, 118, 442-447.
VAN ALLEN, M. I., CURRY, C. & GALLAGHER, L., 1987a. Limb
reduction wall complex: I. Pathogenesis. American Journal of Medical Genetics, 28, 529-548. ZIMMER, Y., SOVA, M. Y., DIVON, M., PERY, M. & PERETZ,
B. A., 1985. Tetra-amelia with multiple malformations of one kindred. European Journal of Pediatrics, 144, 412-414.
Ultrasound demonstration of a leaking hydatid cyst of the liver causing "cyst within a cyst" appearance By B. Banerjee, FRCS, DMRD, FRCR, A. Rennison, BSc(Hons), DCRR and *Q. M. Haque, DMRD, FRCR Department of Diagnostic Radiology & Imaging, Tameside General Hospital, Ashton-Under-Lyne, Lancashire OL6 9RW and *Ormskirk District General Hospital, Wigan Road, Ormskirk, Lancashire L39 2AZ, UK
Based on a poster presented at the BMUS 23rd Annual Meeting in Bournemouth, on 10-12 December 1991 Keywords: Unilocular hydatid cyst, Simple liver cyst, endocyst, "Cyst within a cyst"
Echinococcal disease may affect any part of the body; the liver is the most frequently affected organ (75%) (Saidi, 1976). Although a cyst with internal septation or loculation is the classical ultrasound description of hydatid cyst of the liver, in reality unilocular cysts are more frequently encountered (Sciarrino et al, 1991). On ultrasound unilocular hydatid cysts are usually indistinguishable from innocent simple hepatic cysts, which are common incidental findings during ultrasound examination of the liver. Moreover, in a non-endemic area the index of suspicion is low and the possible diagnosis of hydatid disease may not be entertained when unilocular cysts are detected in the liver. On rare occasions, however, the thin internal membrane, the endocyst, of a unilocular hydatid cyst may separate spontaneously from the thick outer ectocyst, giving rise Address correspondence to Dr B. Banerjee.
604
to the appearance of a cyst with a membrane-like structure beneath its wall. Demonstration of the internal membrane is considered to be pathognomonic of hydatid disease (Beggs, 1983; Garcia et al, 1988) and allows a firm diagnosis of hydatid disease by ultrasound alone. We present a case to illustrate the above mechanism.
Case report A 42-year-old woman presented with dyspepsia and vague right upper quadrant discomfort and underwent ultrasound examination of the abdomen for suspected calculous disease of the gallbladder. Her past medical history was unremarkable and her whole blood count and urine analysis were normal. On ultrasound no calculus was detected in the gallbladder or bile ducts and the gallbladder appeared normal. A thin-walled unilocular echo-free cystic space of 2.7 cm diameter was noted in the right lobe of the liver (Fig. 1). This was diagnosed as a
The British Journal of Radiology, July 1992
Case reports
Figure 1. Longitudinal scan of the liver, demonstrating a unilocular cyst in the right lobe of the liver (arrowheads). There is no evidence of internal echo and there is distal enhancement. A normal gallbladder is seen (curved arrow). simple liver cyst and considered to be an innocent incidental finding. Several days later, the patient attended the Accident and Emergency Department with an acute exacerbation of her symptoms and a clinical diagnosis of acute cholecystitis was made. A repeat ultrasound examination, performed within a short time of her arrival, revealed no evidence of gallbladder disease, but there was a striking change in the appearance of the cystic lesion in the right lobe of the liver. There was now a membrane-like structure partially separated from the inner wall of the capsule of the cyst (Fig. 2) and, while scanning was still
Figure 3 caption and part (c) overleaf. in progress, the sonographer witnessed the complete separation of the internal membrane from the capsule of the cyst, producing a "cyst within a cyst" appearance (Fig. 3). During and after the completion of the separation of the internal membrane the patient did not experience any increased discomfort. A complement fixation test for hydatid disease was positive, confirming the diagnosis. The blood count and liver function tests were normal and on enquiry no definite association with endemic areas of hydatid disease was revealed. The patient was discharged from the hospital within a few days following improvement of her acute symptoms but some vague discomfort persisted. Figure 2. There is partial separation of the internal membrane, the endocyst (curved arrow), from the outer cyst wall, the ectocyst. Vol. 65, No. 775
Discussion
The ultrasound appearance of hydatid cysts of liver is varied. The diagnostic difficulty of "solid" forms of 605
Case reports
hydatid cyst is well documented (Garcia et al, 1988). Unilocular echo-free hydatid cysts may be indistinguishable from simple hepatic cysts by ultrasound. However, demonstration of an internal membrane in such a cyst is considered to be pathognomonic of hydatid; therefore, when serology is negative, demonstration of an internal membrane may be the only indicator of the true nature of the cyst. Detachment of the internal membrane is most likely due to a host defence mechanism or ageing of the parasite (Lewall & McCorkell, 1986). Some authors believe that the univesicular cyst represents the fully developed form of the parasite, and the subsequent stages after rupture of the cyst, namely separation of the internal membrane and formation of daughter cysts, are attempts at survival by the parasite (Barriga et al, 1983). This case illustrates that echinococcal disease should be considered in the differential diagnosis of every cyst in the liver, even though the patient may not have lived in an endemic area. Acknowledgment Thanks to Mr R. Biggs for the photography. References BARRIGA, P., CRUZ, F. V. & LATHROP, R., 1983. An ultrasono-
graphically solid, tumor-like appearance of echinococcal cysts in the liver. Journal of Ultrasound in Medicine 2 (3), 123-125. BEGGS, I., 1983. The radiological appearances of hydatid disease of the liver. Clinical Radiology, 34, 555-563. GARCIA, F. J., MARTI-BONMATI, L., MENOR, F., RODRIGUES, B.
& BALLESTA, A., 1988. Echogenic forms of hydatid cysts: sonographic diagnosis. Journal of Clinical Ultrasound, 16, 305-311. Figure 3. (a) Oblique sagittal view of the right lobe of the liver showing the intact wall of the hydatid cyst, (b) Partial separation of the internal membrane of the cyst (curved arrow) is noted at the beginning of the examination, (c) There is now complete separation of the internal membrane, giving rise to a "cyst within a cyst" appearance (arrowheads) while the ultrasound examination is still in progress.
LEWALL, D. B. & MCCORKELL, S. J.,
1986. Rupture of
echinococcal cysts. American Journal of Roentgenology, 146, 391-394. SAIDI, F., 1976. Surgery of Hydatid Disease (Saunders, Philadelphia), Ch. 3, pp. 31-155. SCIARRINO, E., VlRDONE, R., LOIACONO, O., FUSCO, G., RlCCA, T., COTTONE, M., MARINGHINI, A. & DELLA MONIA, A.,
1991. Ultrasound changes in abdominal echinococcosis treated with Albedozole. Journal of Clinical Ultrasound, 19, 143-148.
606
The British Journal of Radiology, July 1992
