This document describes a case of a 48-year-old male patient presenting with right lumbar pain and swelling for 9 months and 3 months respectively. On examination, a non-tender cystic mass was palpable in the right lumbar region. Investigations including ultrasound and CT scan revealed a renal cyst. The document then provides an overview of renal cysts, discussing simple cysts, complicated cysts, and the Bosniak classification system for cystic renal masses. Based on imaging findings, the patient's cyst was likely a Bosniak Category II cyst.

2. BY
Dr. Muhammad Saifullah
PG Trainee,
Department of Urology, AHF

3. INTRODUCTION
Mr. X.Y.Z , 48 years old, married &
resident of Batala colony, Faisalabad
was admitted via OPD with the
presenting complaint of
 Pain Right Lumbar Region – 9 months
 Swelling Right Lumbar Region – 3
months

4. HISTORY
The patient was in usual state of health 9
months back when he experienced gradual
onset mild pain over the Right lumbar
region. This pain was dull in nature, radiated
to the back and was not associated with
fever, vomiting or hematuria. This pain was
non-progressive, aggravated by itself & was
relieved by oral medication (No record
available)

5. 6 months later, he noticed swelling
over the Right lumbar region when he
was taking bath. The swelling was
initially small but was gradually
progressive. This swelling was also not
associated with fever, vomiting or
hematuria.

6. PAST HISTORY
 No history of any previous similar episode.
 Known case of Heart disease – 20 years
 History of Appendectomy – 15 years
 History of open reduction and internal
fixation of Left Radius & Ulna – 10 years

7. FAMILY HISTORY
• No family history of DM, HTN, TB or
IHD.
• Both parents alive and healthy.
 Govt. Employee.
 Smoker – 30 years.
 Middle socio-economic class.
SOCIAL HISTORY

9. GENERAL PHYSICAL
EXAMINATION
A middle aged man of average built
lying comfortably on the couch with
following vitals:
 Pulse…. 88/min
 BP…. 110/70
 R/R…. 16/min
 Temp…. 98.6 oF

10.  NAILS…No Pallor, clubbing, koilonychia, splinter
hemorrhages or cyanosis.
 FINGERS… No Osler’s, Heberden’s or Bouchard’s
nodes, Joint swelling or deformity.
 PALM… No sweating, palmar erythema or dupuytren’s
contracture.
 FACE… No puffiness, proptosis, jaundice, xanthelasmas
or central cyanosis. Good oro-dental hygiene.
 NECK… No thyroid swelling, engorged neck veins or
palpable cervical lymph nodes.
 FOOT… No edema, cyanosis or loss of hair.

11. ABDOMINAL
EXAMINATION
 Abdomen scaphoid with normal shaped
umbilicus, central in position. Peristalsis not
visible. Fullness of Right Lumbar region.
No visible scars, striae or veins. Hernial
orifices are intact.
 Abdomen was soft and non-tender. A cystic
non-tender mass palpable occupying the
Right lumbar region which was not
reducible or compressible. Kidneys
billaterally not palpable. No
visceromegaly.

12.  Abdomen was resonant on percussion
except right lumbar region where dullness
was present. No Shifting dullness.
 Bowel sounds 2-3 per minute with no
audible bruits or succussion splash.
 DRE. Normal
 Rest of the examination was unremarkable.

14. INVESTIGATIONS
 HB  14.3 mg/dl
 E.S.R  12 after 1st hour
 T.L.C  7,700
 neutrophils 79 %
 lymphocytes 16 %
 monocytes 03 %
 eiosinophills 03 %
 Platelets count  1,28,000

15.  R.B.S  96
 Urea  44 mg/dl
 Creatinine  0.7 mg/dl
 Billirubin total  0.8
 SGOT(AST)  38
 Alk phosphatase  211
 HbsAg ---> neg
 Anti Hcv ---> neg

16. ECG

17. Echocardiography

18. Ultrasound KUB

19. Cystogram

20. CT Scan KUB with
contrast

22. OUTLINE
 Introduction
 Simple Cysts
 Differentials
 Complex/Complicated Cysts
 BOSNIAK Classification
 Management according to BOSNIAK
Categories

23. A cyst is a closed sac, having a
distinct membrane and division
compared to the nearby tissue.
Cyst is a Greek word meaning “Fluid
Filled Sac”
It may contain
 Air
 Fluids
 Semi-solid material

24. If this cavity lacks a distinct
membrane, it is called PSEUDOCYST.
If it is filled with pus, it is called an
ABSCESS.

25. RENAL
CYST
A renal cyst is
a fluid collection
in the kidney.

26. 27-35 % of individuals greater than
50 years of age may have asymptomatic
simple renal cysts.
Prevalence increases with increasing
age and by the age of 70 years almost
every person has a simple renal cyst.

27. SIMPLE CYSTS
 Simple cysts arise from
obstructed tubules or ducts.
 They do not communicate
with collecting system.
 Commonly asymptomatic
 Hematuria (from cyst rupture)
 Infection (Abscess)
 Mass effect from large cysts
may cause dull ache or
discomfort.

28. HYPERDENSE CYST
A hyperdense cyst a simple kidney cyst
that has blood as part of the contents of
the cyst.
A hyperdense kidney cyst is not
suspicious for kidney cancer and is just
another type of simple kidney cyst.

31. Intravenous Urography
 A lucent mass may be seen within the renal
parenchyma.
 A "claw" sign may be seen if the cyst
extends beyond the surface of the kidney,
and represents the adjacent stretched
parenchyma. If the cyst is completely
intrarenal, the thickness of its wall cannot
be assessed.
 Radiographs taken 1-2 minutes after IV
contrast injection optimally visualize a
cyst.

32. Lucent defect
Cortical bulge
Round indentations on
collecting system
"Beak sign" can be
seen with large cysts.

33. Radiographic features , US:
Anechoic
Enhanced through-transmission
Sharply marginated,
smooth walls

34. Radiographic features , CT:
Smooth cyst wall
Sharp demarcation
Homogenous Water
density (< 10-15 HU)
No significant enhancement
after IV contrast (<5HU)
Cyst wall too thin to be seen by CT

35. Be Careful:
Cysts that contain calcium, septations, and irregular
margins (complicated cysts) need further workup
True renal cysts should always be differentiated from
hydronephrosis, calyceal diverticulum, and peripelvic cysts.
Differentiate renal cyst from hypoechoic renal artery
aneurysm using color Doppler US and Angiography

36. Hydronephrosis:

37. Calyceal Diverticulum
Parapelvic Cyst

38. Renal Artery Aneurysm

39. Complicated CYSTS
Complicated cysts are cysts
that do not meet the criteria
of simple cysts and thus
require further workup.
• Internal debris
• Echogenic clot
• Fluid-debris levels
• Thick septations
• Thick walls
• Thick or coarse calcification

40. Increased CT density (> 15 HU) of cyst content
Vast majority of these lesions are benign.
High density is usually due to hemorrhage, high protein
content, and/or calcium.
Radiographic Features of Complicated Cysts
Septations
Thin septa within cysts are usually benign.
Thick or irregular septa require workup.
Calcifications
Thin calcifications in cyst walls are usually benign.
Milk of calcium: collection of small calcific granules in cyst
fluid: usually benign
Thick wall
These lesions usually require surgical exploration.

44. BOSNIAK Category I
Benign simple cyst with:
 Thin wall without septa
 No calcifications
 No solid components
 No contrast enhancement.
 Density equal to that of water

45. Simple renal cyst, Bosniak Category I.

46. BOSNIAK Category II
Benign cyst with
 A few thin septa
 May contain fine calcifications
 Homogenous lesions less than 3 cm
with sharp margins
 Without enhancement

47. Bosniak Category II cyst
Curvilinear calcification within a thin septum

48. Bosniak Category II cyst
Homogeneously hyperdense mass No increase in Density after IV contrast

49. Bosniak Category II cyst
Cyst with several internal
septations and a minimally
thickened wall

50. Bosniak Category II cyst.
Cyst with uniform, mild wall thickening
and short, interrupted calcifications

51. Bosniak Category II hyperdense cyst.

52. Bosniak Category II cyst

53. Bosniak Category II cyst.
Nearly completely calcified mass with no obvious
enhancing elements

54. Bosniak Category II.
subcentimeter rim calcified renal
cyst

55. BOSNIAK Category IIF
Well marginated cysts with
 A number of thin septa, with or without
mild enhancement or thickening of
septa.
 Thick and nodular calcifications may
be present
 No enhancing soft tissue components
 Non enhancing lesions 3 cm or larger.

56. BOSNIAK Category IIF

58. BOSNIAK Category III
Indeterminate cystic masses with
 thickened irregular septa with
enhancement.
 multilocular, encapsulated mass
Increase in Hounsfield Units of the mass after
contrast injection….. ENHANCEMENT
(>15% = enhancement = surgical on MRI)

60. Bosniak Category III.
cystic mass with irregular wall thickening and
associated heterogeneous nonenhancing elements

61. Bosniak Category III complex cyst.
multilocular, encapsulated mass

62. Bosniak Category III complex cyst.
Thick-walled, encapsulated,
multilocular cystic mass with
enhancing septa

63. BOSNIAK Category IV
Malignant cystic masses with
 All the characteristics of category III
lesions
 Enhancing soft tissue components
independent of but adjacent to the
septa.

67. Bosniak
Category IV
cystic
neoplasm.

68. Bosniak Category IV cystic neoplasm

69. A 42-year-old female with back pain, hematuria, and a
renal mass discovered by lumbar spine MR.
hyperdense (55
HU) 3 cm mass.
enhance to 88 HU after IV
contrast
Renal cell carcinoma

70. BOSNIAK CLASSIFICATION
Category (Bosniak) US Features Workup
Type 1: Simple cyst Round, anechoic, thin wall
enhanced through
transmission
None
Type 2: Mildly
complicated cyst
Thin septation, calcium in
wall
CT or US follow-up
Type 3: Indeterminate
lesion
Multiple septae, internal
echos mural nodules
Thick septae
Partial nephrectomy,
biopsy
CT follow-up if surgery
is high risk
Type 4: Clearly
malignant
Solid mass component Nephrectomy

71. To identify size criteria for complex cystic renal masses that
can distinguish renal cell carcinoma from benign cysts
supplementing the Bosniak classification

72. To identify size criteria for complex cystic renal masses that
can distinguish renal cell carcinoma from benign cysts
supplementing the Bosniak classification

73. To identify size criteria for complex cystic renal masses that
can distinguish renal cell carcinoma from benign cysts
supplementing the Bosniak classification
Malignancy was significantly associated with
1. cyst size (>2 cm)
2. male gender
3. younger patient age (<50 years).
According to the Bosniak classification,
 no category I cyst
 all 8 category II cysts were benign
 3 of 18 (17%) category IIF cysts were malignant
 21 of 39 (54%) category III cysts were malignant
 29 of 32 (90%) category IV cysts were malignant.
All category IIF cysts were benign in patients older
than 50 years of age

74. Treatment
Treatment is not needed for asymptomatic simple
kidney cysts.
 Simple kidney cysts may be monitored with
periodic ultrasounds.
 Simple kidney cysts that are causing symptoms
or blocking the flow of blood or urine through the
kidney may need to be treated using a procedure
called sclerotherapy.
 If the cyst is large, surgical excision may be
needed.

75. In SCLEROTHERAPY, the doctor
punctures the cyst using a long needle
inserted through the skin. Ultrasound is
used to guide the needle to the cyst. The
cyst is drained and then filled with a
solution containing alcohol to make the
kidney tissue harder. The procedure is
usually performed on an outpatient basis
with a local anesthetic.

76. MANAGEMENT
Ignore, Follow or Excise
Renal cysts can be classified
according to the Bosniak classification
depending on their features.
Type I cysts are simple cysts.
Type II are the minimally complicated
cysts.
Type I and II can be ignored.

77. Type II F are probably benign, but need
to be followed.
Type III and IV both are surgical
lesions.
Type IV is inevitably malignant and in
the type III group about 80-90% turn out
to be malignant as well

80. ANY QUESTIONS
??????