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Indian Journal of Basic and Applied Medical Research; June 2016: Vol.-5, Issue- 3, P. 817-821
817
www.ijbamr.com P ISSN: 2250-284X , E ISSN : 2250-2858
Case report
Primary renal hydatid cyst masquerading as matrix renal stones
1Dr BawanaRaina , 2Dr Ajay Misri , 3Dr MonalTrisal ,4 Dr Naveen Kumar
1Deptt of Pathology. AcharyaShriChander College Of Medical Sciences. Sidhra, Jammu-180017
2Department of Surgery, Police Hospital Gandhi Nager, Jammu,180004.
3Department of Pathology and Transfusion Medicine, Dharamshila Hospital And Research Centre , New Delhi- 110096
4Department of Medicine, Fortis Hospital Sector - 44, Opposite HUDA City Centre, Gurgaon, Haryana 122002
Corresponding author: Dr Monal Trisal
Abstract
Human hydatidos is affect several organs in body. Primary isolated kidney involvement is very rare. We present a case of
incidentally discovered hydatid disease encountered during elective pyelolithotomy for renal matrix stones. It was managed by
cyst enucleation without sacrificing the kidney, followed by course of albendazole. The patient showed no evidence of recurrence
till the end of one year follow up. The case emphasises the need to keep broad differential in such cases and to use of advanced
imaging technique to narrow down them, so that more accurate decision about their management can be taken.
Keywords – Hydronephrosis, Hydatidosis, Hydatid cyst, Isolated renal hydatid.
Background
Echinococcosis or hydatidosis is caused by
tapeworm, Echinococcusgranulosus, which belong to
order cestoda, family taenia. Its prevalence is highest
in cattle and sheep raising regions of world, such as
Middle East, Central Europe, Australia, Asia and
South America. The disease affects mainly the
gastrointestinal and pulmonary system.1Most
commonly affected organs are liver(75%)followed
lungs(15%), which act as filters for the
worm.2,3Kidneys are uncommonly involved, usually
along with other organs and comprises only 2-3% of
all cases.2 An isolated involvement of kidneys is even
rarer. Here we report a case, which on the basis of
history and investigation appeared to be soft matrix
renal calculi, for which elective pyelolithotomy was
planned. But to our surprise, it turned out to be
isolated renal hydatid cyst.
Case Presentation
A 33 year old female presented with complaints of
recurrent left lumbar region pain for last six months,
followed bydysuria for about four months. The pain
was episodic, dull aching to colicky in nature,
involving renal angle, some time associated with
vomiting. In last four months, she also had episodes
of dysuria and fever, which were treated with course
of antibiotics. In physical examination, there was no
tenderness in the left renal angle, left hypochondrium
or lumbar region. Ultrasound (USG)of the whole
abdomen revealed: multiple (6-7), soft, echogenic
matrix calculi, with faint acoustic shadow in all
calyceal groups of the left kidney, largest 26mm; left
sided moderate hydronephrosis with echogenic debris
within the hydronephrotic sac; cortico-medullary
differentiation was maintained (figure -1). The rest of
the abdominal ultrasound was normal. Intravenous
urography (IVU) was done and which showed no
excretion of contrast from the left kidney,delayed
nephrorgram at 6 hr with filling defects; finding was
suggestive of left stag horn soft calculuswith
Indian Journal of Basic and Applied Medical Research; June 2016: Vol.-5, Issue- 3, P. 817-821
818
www.ijbamr.com P ISSN: 2250-284X , E ISSN : 2250-2858
pyonephrosis and suppressed function. Renal scan
showed 30% split function of the left kidney.In
routine investigations haemoglobin was 11.2 gm/dl,
total leucocyte count was 10000/cc and differential
leucocyte count was N-70/L-26/E-4/M-1.Liver and
kidney function tests, serum electrolyte, random
sugar, chestX ray were normal. Urine routine
examination had 20-25 pus cells per high power
field.We first treated the urinary tract infection.Then
on the basis ofmatrix stones with hydronephrosis on
USG, delayed nephrogram of left side on IVU and
reduced but preserved left renal function on scan, we
planned left pyelolithotomy. When pyelotomy was
made, multiple cystic masses popped out, which
raised the suspicion of renal hydatid disease. The
lesion was excised and precautions were taken so that
there was no spillage of cystic contents. In gross
examination, cyst was 8.5 X6.5 cm, single,
multiloculated, grey white, fluid filled, appearing as
bunch of grapes (figure-2). The microscopic
examination revealed a lamellated fibrochitinous cyst
wall which contained scolices and brood capsule
(figure-3) and there were also areas offocal
calcification of the wall. Patient was given a post-
operative course of Albendazole with view to
decrease the risk of recurrence. Her post operative
stay was uneventful and patient was discharged on a
regime of Albendazole: 3 cycles of 400mg given
twice a day for 28 days with an interval of 14 days
between cycles. The patient showed no evidence of
recurrence at the end of 1 year follow up.
Figure 1: USG abdomen shows soft renal calculi with
faint acoustic shadow.
Figure 2: Grey coloured multiloculated hydatid cyst
removed from left kidney, appearing as bunch of
grapes.
Figure 3: Shows lamellated fibrochitinous hydatid
cyst wall (pericyst) and the inner endocyst with
daughter cyst (H&E.40X).
Discussion
Matrix calculi are an uncommon form of renal stones.
They are composed of protein, sugars, glucosamines,
and water. Being soft, they conform to the shape of
1
3
2
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the ureter or calayx. The diagnosis is usually made at
surgery, as it is very difficult to suspect them in
radiographic investigations.4They are usually
radiolucent non-opaque calculi and are difficult to
diagnose on plain X-ray abdomen or IVU. In IVU
they appear as radiolucent filling defect.
Ultrasonographycan identify them, but depending on
the amount of mineralization, acoustic shadowing
may or may not be present. CT can distinguish them
from other causes of radiolucent filling defects in the
collecting system. They are best treated by
percutaneous or surgical extraction. As they are
gelatinous in nature and lack a crystalline structure,
extracorporeal shock wave lithotripsy (ESWL) is
generally unsuccessful and not recommended. In our
case also, the lesions were multiple, fitting into
calyces, with faint acoustic shadowing thus
suggesting matrix calculi. IVP also only showed
reduced renal function with filling defects. As on
renal scan, function of kidney was reduced but not
absent, and we suspect matrix calculi, we planned
pyelolithotomy and not ESWL or nephrectomy. But
too our surprise, it turned out to be hydatid cyst.
There was no sign of disease anywhere else in USG
abdomen, and being a closed cyst, there was no
hydatiduria in urine routine examination. Moreover,
finding on USG were not typical of hydatid disease
(unilocular or multilocular cystic mass with daughter
cysts). Hence we didn’t suspected it, and didn’t went
for CT abdomen. Similar to our case, Nandwaniet
al5also reported a case where they confused renal
hydatid cyst with calculus and diagnosis was
suspected only during planned
percutaneousnephrolithotomy.
Echinococcosis is a zoonosis with worldwide
prevalence, caused by the larval stage of the
echinococcus tapeworm. The adult worm lives in the
proximal small intestines of the definitive host
(usually a dog). They release eggs, which are
excreted in the feces. Humans become accidental
intermediate hosts either through contact with a
definitive host, or ingestion of contaminated water or
vegetable.3The larvae penetrate the intestines to enter
the portal venous system and lymphatics; via them
they travel to the liver which acts as the first line of
defence.From their they can reach lungs which act as
second site of filtration of the hydatid cyst.
Hematogenous dissemination from these two primary
locations can secondarily involve any organ in body.3
Kidney involvement is rare(2-3%) even in
endemic area,as it hasto crossabove mentioned lines
of defence of liver and lung.6It has been postulated
that the cysts passes through portal system into the
liver and finally via retroperitoneal lymphatics
reaches kidney.7They are most commonly solitary
and located in renal cortex, generally in either of the
pole.6The hydatid cyst of kidney can of three type:
closed, exposed and open. It is called close type when
all three layers of cyst are intact. When the cyst is no
longer protected by the third layer (pericyst) ,it is
called an exposed cyst. If all the three layers of the
cyst have ruptured, and there is free communication
with the drainage system of kidney, it is called an
open or communicating cyst. Cystic rupture into the
collecting system, leads to passage of daughter cysts
into the urine, causing hydatiduriawhich is
pathognomic of renal hydatidosis. It is usually
microscopic and is seen only in 10-20% of cases.7
Gross hydatiduria is uncommon but diagnostic. The
patient usually remain asymptomatic for years and
later may present with the symptoms of hydatiduria,
lumbar region pain, hematuria, pyuria or intermittent
fever.2,3
Eosinophilia is a feature in about 25-50% cases.8
Indian Journal of Basic and Applied Medical Research; June 2016: Vol.-5, Issue- 3, P. 817-821
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Serological tests in primary renal hydatidosis are
usually negative; but it does not exclude hydatid
disease. Positive serology neither confirms the
diagnosis, nor correlate with pathological stage; it
just have a supportive role and suggest further work-
up.9Although not specific, radiological studies may
provide clue for preoperative diagnosis.A high index
of suspicion for hydatid disease should be maintained
while evaluating complex cystic renal masses.On
plain X ray abdomen, it can appear as soft tissue
mass or ring shape calcification;0.9% of calcified
renal mass can have renal hydatidosis.9IVP reveals
mostly distortion of calices, calical ectasia as a result
of mass involving the collecting system or reduced
function of kidney. Ultrasonography usually
demonstratesunilocular or multilocular cyst. In 2003
WHO-IGWE classified thetypes of HC according to
disease activity: pure cyst or those having dominant
cystic components with hydatid sand (types 1 and 2
respectively) indicates active disease; cysts having
detached membranes, daughter cysts or solid
septationsare the transitional or ‘in process of dying’
stage (type 3); and those having solid appearance
(types 4 and 5) are suggestive of inactive
disease.10CT scan is more sensitive and accurate than
USG,and it has some important advantages: it can
more easily detect calcification, daughter cysts,
intracystic infection, communication with the urinary
tract, extra renal disease and can more easily
differentiate WHO stage 4 cyst from urinary tract
tumor and abscess.9
Histopathologically there is an outer laminated non-
nucleated layer made up of layers of gelatine. Outside
this layer there is a pericyst which is formed as a
result of inflammatory reaction of the host. Over a
period of time it makes a dense fibrous capsule.
There is an inner germinal layer gives rise to
daughter cysts. The cysts eventually become
leaky,resulting in shrinkage, fibrosis and eventual
calcification. The parasite structure are completely
destroyed, with only degenerated scolices remaining
intact along withy ellow paste like cholesterol rich
debris.11
As medical treatment is insufficient to cure
and interventional radiology is quite risky, surgery is
usually the treatment of choice in renal hydatid cyst.
Kidney-sparing surgery is possible in 75% cases of
intra pelvic renal hydatid; but nephrectomy may be
needed in remaining25% cases when ithas been
totally destroyed by the cyst.12,13,14Care should be
taken to prevent spillage which can result in
anaphylactic reaction and dissemination of disease.
Pre-operative courses of albendazole is recommended
for cyst sterilization, decreasing risk of
anaphylaxis(as it become non-antigenic) and to
reduce pressure within the cyst (thus reducing the
risk of spillage). Post-operative course of up to 3
months is recommended to reduce the recurrence of
disease, especially when cystic fluid has spread
during surgery.15Albedazole with or without puncture
aspiration- injection-re-aspiration (PAIR) is indicated
in patients with WHO stage 1 hydatid cyst, cyst
containing severaldaughter cyst, inoperable disease,
patients who cannot tolerate surgery and who do not
wish to undergo surgery.
Learning Points
1. Hydatid disease may present in unusual
ways leading to diagnostic difficulty and
management problems.
2. Isolated renal involvement caused by
Hydatid cystis a rare occurrence. A high
index of suspicion for hydatid disease
should be maintained while evaluating
renal masses.
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3. Preoperative diagnosis using advanced
radiological technique is important,
failing which there is risk of
anaphylactic reactions during surgery
and disease recurrence their after.
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4. Singh H, Pandey S, Dorairajan LN, Kumar S. Acute renal failure due to bilateral matrix renal calculi- a diagnostic
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