Hydatid disease is an endemic zoonosis in many parts of the world and is also an important public health and socioeconomic concern in India. It may manifest as a cystic hydatid disease caused by Echinococcus granuloses or alveolar hydatidosis caused by Echinococcus multilocularis. The most commonly affected sites are liver (66%) and lung (25%), but other organs like spleen, kidney, adrenal glands, brain, muscle, heart, bone, pancreas can also be affected1.
We encountered a rare case of recto-sigmoid hydatid cyst that was masquerading as left adnexal mass.
Case Report
A 52-year-old lady resident of Bihar, presented to us with history of bloating, decreased appetite, and significant weight loss (about 7 kg weight loss) for 6-7 months. There was no associated history of chronic cough or fever, altered bowel bladder habit, pain in abdomen or jaundice or vomiting. Abdomen and pelvic examination findings were unremarkable. Blood investigations were unremarkable.
A contrast enhanced computed tomography (CECT) of the abdomen and pelvis was done that revealed a 7.7 x 7.8 cm left-sided well-defined multi-loculated and multi-septate mass lesion within the pelvis. There was anterior abutment of the urinary bladder and vaginal vault without any obvious infiltration. The impression was of a probable benign left adnexal mass, suspicious of left complex ovarian cyst.
Exploratory laparotomy was done, and a 10 x 10 cm spherical mass was found in the pelvis that was arising from the wall of antero-lateral rectal wall at the rectosigmoid junction. The mass was translucent with multiple daughter cysts present. We injected hydrocortisone 100 mg and pheniramine 4 mg intra-operatively as a prophylaxis for anaphylaxis while resecting the specimen. The surrounding tissue was separated from the cyst with the help of betadine-soaked sponges and cyst was carefully dissected from the rectal wall without any spillage. All viable daughter cyst and germinal layer were removed and pericyst was excised from the rectal wall.
Post-operative course was uneventful, and patient was discharged on 4th post-operative day with oral analgesics and tablet albendazole 400 mg. Histopathology revealed multiple acellular laminated membranes (ectocyst) along with numerous hooklets and confirmed the diagnosis of hydatid cyst.
Discussion
Hydatidosis should be considered in the differential diagnosis, both in endemic and non-endemic areas. Theoretically, they can occur anywhere in the body except hair, teeth and nails2. They are more frequently encountered in the liver, lungs, peritoneum and kidney3. Extra-hepatic and extra-pulmonary primary hydatid diseases are rare and mostly isolated cases are reported. Hydatidosis is a localized disease, but it may show widespread features, proving to be fatal. Extrahepatic hydatid disease may remain asymptomatic for many years. Clinical symptoms may arise depending on the organ affected or when the cyst is large enough to be palpable.4,5
The incidence of peritoneal hydatid disease is only around 13%4. Unusual sites of hydatid disease are the muscles (0.8%), brain(2%) or retroperitoneum (1.1%)4. Isolated primary extra hepatic hydatidosis has been seen within the abdominal cavity with an incidence of around 6%-11%5. The growth rate of the cysts is reported to beonly about 1 cm/year5.
The classical theory of development proposes that rupture or fissuring of a primary cyst in liver, spleen or mesentery can lead to seeding of its contents in the abdominal cavity1. The primary cyst might heal and disappear completely, leaving a scar behind which can be easily overlooked on radiology. The cysts when located in the pelvis that is in close proximity to boundaries of rectum and bladder are peritoneal and may be adherent to the serosa of the bowel.
A pre-operative diagnosis from radiological scan is difficult unless strong suspicion is kept in mind. CECT offers the best diagnostic aid (sensitivity of 90-97% for typical sites) but classical features of hydatid cyst may not always be present3. Abdominal cystic lesions (i.e., mesenteric cysts, ovarian cysts, enteric duplication cysts, lymphangioma) must be considered in the differential diagnosis. It is important to note that in such cystic lesions, fine needle aspiration or any biopsy technique must not be attempted and a high index of suspicion for hydatid disease must be kept in mind.
Surgery is the main stay in the management of hydatid cysts. Pericystectomy or total cyst excision is performed. Surgical goal is to completely remove all the cysts with its contents, without any contamination of the field. There is high risk of rupture and spilling of cyst content while dissecting between the cyst and the laminated external membrane. In cases where the cyst ruptures into the peritoneum, it may lead to disseminated hydatidosis or anaphylactic shock. When a cyst is adhered to vital structures, partial cyst excision or pericystectomy (excision of the cyst leaving areas in contact with the organs) may be done. In high-tension hydatid cysts, controlled evacuation of the cyst content is done to avoid intra-operative rupture of the cyst and seeding of the contents. Betadine soaked gauze or 30% hypertonic saline solution can be used as scolicidal agents for local irrigation. Administration of anthelminthic therapy like albendazole (400 mg twice a day given for 3-6 months) has been shown to prevent recurrence of the cysts2.
A systematic review of hydatidosis of colon done by Latatu-Cordoba et al16 reported 9 cases of secondary colonic hydatid disease from hepatic or splenic primary. In our case, the liver and lung were found to be normal in radiological work up and also during intra op inspection.Thus extrahepatic, extra pulmonary primary hydatid disease is rare finding and scarcely reported in literature. No case of primary rectal hydatid cyst has been reported in literature till date.
A case of recto-sigmoid hydatid cyst is a rare diagnosis. During a pre-operative work-up of a cystic lesion in the abdomen, a differential diagnosis of hydatid disease must always be kept in mind. Clinical findings may be vague, and radiology is not always sensitive in diagnosing unusual sites of hydatid cyst. In case of any suspicion of hydatid cyst in the abdomen, it must not be biopsied and careful intra-operative handling and in-toto excision of the cyst should be carried out with no spillage into the peritoneal cavity. Post operative anti-helminthic treatment is beneficial in most cases.
Conclusion
Recto-sigmoid hydatid cyst is an extremely rare entity. A strong clinical suspicion and careful intra-operative excision can help in eliminating serious complications.
Reference
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- Budke CM, Carabin H, Ndimubanzi PC, Nguyen H, Rainwater E, Dickey M, et al. A systematic review of the literature on cystic echinococcosis frequency worldwide and its associated clinical manifestations. Am J Trop Med Hyg. 2013;88:1011-27.
- Khurana S, Das A, Malla N. Increasing trends in seroprevalence of human hydatidosis in North India: A hospital-based study. Trop Doct. 2007;37:100-2.
- Giri S, Parija SC. A review on diagnostic and preventive aspects of cystic echinococcosis and human cysticercosis. Trop Parasitol. 2012;2:99-108.
- Ibanez N, Fern´andez JA´, G´omez A´J, Parrilla P. Right-colon mucinous adenocarcinoma mimicking a hydatid cyst. Rev Esp Enferm Dig. 2018;110(3):196-197.