Clinical Radiology (1987) 38, 55-57

Multilocular Cystic Nephroma: Report of Three Cases A N N E G A R R E T T , H E L E N C A R T Y and D A V I D P I L L I N G

Alder Hey Children's Hospital, Liverpool

Multilocular cystic nephroma is an uncommon renal neo- plasm which in childhood usually presents as an abdominal mass. The same condition is also described as multilocular kidney and muitilocular cystic hamartoma. The clinical presentation, and radiological findings in three cases of multilocular cystic nephroma are described.

A l t h o u g h ce r ta in cl inical and rad io log ica l f ea tu res of mul t i locu la r cyst ic n e p h r o m a s m a y mimic those of W i l m ' s t u m o u r , it is poss ib le by the use of u l t r a sound to have a s t rong susp ic ion of the correc t d iagnosis p re - ope ra t ive ly , thus obv ia t ing the need for c h e m o t h e r a p y .

Since it was first d e s c r i b e d by E d m u n d s (1892) fewer than 100 cases have b e e n r e p o r t e d . In the p e r i o d f rom March 1982 to J a n u a r y 1985 th ree cases of mu l t i l ocu la r cystic n e p h r o m a have b e e n d i agnosed and t r e a t e d at A l d e r H e y C h i l d r e n ' s Hosp i t a l . Two p r e s e n t e d as a b d o m i n a l masses and one was an inc identa l f inding on in t ravenous u r o g r a p h y .

CASE REPORTS

Case 1. A 21-month-old male child was admitted for division of tongue tie and on pre-operative examination a hitherto undisclosed mass was palpated in the left side of the abdomen. Intravenous urogra- phy confirmed a large left sided renal mass which was distorting and displacing the renal pelvis (Fig. 1). There was no evidence of infiltra- tion via the inferior vena cava. Ultrasound examination showed the lesion to be low density and, on close inspection, to contain multiple regular cystic areas. The patient was considered to have a Wilm's tumour and a left nephrectomy was performed, the operation being covered by a single intravenous dose of vincristine. Examination of the resected specimen showed a polycystic mass surrounded by a rim of normal renal tissue. The mass itself comprised dysplastic tubules and cysts in a loose mesenchyme with no evidence of malignancy. After a good post-operative recovery the patient was discharged and has remained well.

Case 2. A 14-month-old male child was admitted for investigation of a large left sided abdominal mass which was an incidental finding during a consultation arranged for screaming attacks.

Intravenous urography confirmed that the mass was renal and ultra- sound showed it to be multicystie in nature (Figs 2, 3). Pre-operatively the suspected diagnosis was multilocular cystic nephroma. Laparo- tomy was performed and a large cystic mass surrounded by normal renal tissue removed.

Histology showed the features of a multilocular cystic nephroma. The boy made a good recovery and was discharged from follow-up 9 months later.

Case 3. An 8-month-old male child was admitted for evaluation of a left sided abdominal mass which first became evident on intravenous urography (Fig. 4). Although the indication had been a single, proven urinary tract infection, at the time of urography the mass was easily palpable. Interestingly, the child had been admitted to hospital 3 weeks previously for an upper respiratory tract infection and on physi- cal examination at that time, there were no abnormal findings in the abdomen. It seems that the mass grew at an alarmingly rapid rate and indeed increased in size clinically in the days immediately preceding operation.

Ultrasound demonstrated a multilocular cystic lesion (Fig. 5) and a diagnosis of mulfilocular cystic nephroma was made.

Examination of the nephrectomy specimen showed a large cystic lesion surrounded by compressed renal tissue and histology confirmed a multilocular cystic nephroma. Again the child made an uneventful and complete recovery.

D I S C U S S I O N

Mul t i l ocu l a r cystic n e p h r o m a is u n c o m m o n and is cha rac t e r i s ed by a we l l - c i r cumscr ibed e n c a p s u l a t e d mass tha t conta ins mul t ip le n o n - c o m m u n i c a t i n g f luid- f i l led loculi . Mic roscop ica l ly the loculi a r e l ined by epi- t he l ium and s e p a r a t e d by a d is t inct s t r o m a ( M a d e w e l l et al., 1983).

T h e r e are two peaks in the i nc idence of the t u m o u r , one in ch i l dhood and one in m i d d l e age. M o s t c h i l d h o o d cases occur b e t w e e n the ages of 3 m o n t h s and 4 years and 73% of these are males . A l l t h r e e cases r e p o r t e d he re we re males who p r e s e n t e d wi thin this age range . the s econd p e a k compr i se s f ema le s of 40 to 60 yea r s of age. B e t w e e n these two age c lus ters , cases a re very r a re and all female .

A f f e c t e d ch i ldren c o m m o n l y p r e s e n t wi th an a b d o m i - nal mass and such pa t i en t s are , t h e r e f o r e , o f t en though t to have W i l m ' s tumours . I n t r a v e n o u s u r o g r a p h y shows a rena l mass in a func t ion ing k i d n e y which d i s tor t s and d isp laces the calyces, ind i s t ingu i shab le f rom tha t seen in a W i l m ' s t umour . The a p p e a r a n c e s on u l t r a s o u n d a re far m o r e specif ic and m o r e l ike ly to l e ad to the cor rec t pre- o p e r a t i v e d iagnos is of mu l t i l ocu l a r cyst ic n e p h r o m a . In the t h r e e cases desc r ibed he re , t he mul t icys t ic na tu re of the t u m o u r was well v isual ised w h e n sep ta we re seen to d iv ide the mass in to mul t ip le locul i of r e gu l a r d is t r ibu- t ion and s imilar size.

The u l t rason ic a p p e a r a n c e o f a W i l m ' s t u m o u r is usual ly one of an echogen ic mass . A r im of n o r m a l r ena l t issue m a y be seen a r o u n d the t u m o u r , ind ica t ing its rena l or igin . La rge W i l m ' s t u m o u r s m a y have necro t ic a reas which are t r anson ic on u l t r a s o u n d e xamina t i on . These a reas a re usual ly i r r egu la r and t h e r e is o f ten echogen ic debr i s wi th in the nec ro t i c a rea . A r a r e r a p p e a r a n c e of a W i l m ' s t u m o u r is tha t o f a mul t icys t ic n e p h r o b l a s t o m a in which the t u m o u r is c o m p o s e d of mu l t ip l e th in -wal led cysts ( W o o d et al., 1982). This a p p e a r a n c e m a y closely r e s e m b l e a mu l t i l ocu l a r cystic n e p h r o m a on u l t r a sound e x a m i n a t i o n and d i f fe ren t ia - t ion of the two cond i t ions m a y be imposs ib l e . I t is easy , h o w e v e r , to d is t inguish mu l t i l ocu l a r cystic n e p h r o m a f rom the m o r e f r equen t ly seen u l t r a son ic a p p e a r a n c e o f a W i l m ' s t u m o u r while they r e m a i n ind i s t ingu i shab le at i n t r avenous u rog raphy .

Mesob la s t i c n e p h r o m a is a r a re congen i t a l t u m o u r and p re sen t s in the n e o n a t a l p e r i o d as a p a l p a b l e mass in the loin. This t u m o u r can also r a re ly a p p e a r to be com- p o s e d o f mul t ip le cysts on u l t r a s o u n d e x a m i n a t i o n and could t h e r e f o r e have the s ame a p p e a r a n c e s as a mul t i - locu la r cystic n e p h r o m a . H o w e v e r , a mu l t i l ocu l a r cystic

56 CLINICAL R A D I O L O G Y

Fig. 1 - Case 1, intravenous urography. There is distortion of the left pelvicalyceal system by a huge mass. The appearances are typical of those which would be more commonly seen in a Wilm's tumour.

Fig. 3 - Case 2, u l t rasound examination. The kidney is replaced by multiple cysts of varying size.

Fig. 4 - Case 3, intravenous urography. A large mass is seen in the left kidney distorting the collecting system.

Fig. 2 - Case 2, intravenous urography. Appearances very similar to Case 1.

nephroma is not a turnout that occurs in the neonatal period so there should be no diagnostic confusion.

Another cause of a multiloculated cystic renal mass is a multicystic kidney, which, ultrasonically, appears as a collection of cysts of different sizes which form an irregular mass (Stuck et al., 1982). Differentiation f rom multilocular cystic nephroma is easier as a multicystic kidney will show no function on intravenous urography or on a 99mTc dimercaptosuccinic acid scintigram. There is function in the kidney in multilocular cystic nephroma.

The pathogenesis of multilocular cystic nephroma is uncertain but it has been postulated that this tumour and

MULTILOCULAR CYSTIC NEPHROMA 57

Fig. 5 - Case 3, ultrasound examination. The typical cystic appearances are again seen in the kidney.

nephroblastoma have a common origin and proceed along different lines (Madewell et al., 1983). This theory would account for the occasional finding of microscopic foci of nephroblastoma within multilocular cystic nephroma. The presence of such tissue is not necessarily an indication for post-operative radiotherapy or chemo- therapy (Akhtar and Qadeer, 1980). Metastases have not been described in childhood cases but sarcomatous stroma has been seen in the tumours of some adult patients and such tumours have metastasised. The treat- ment of multilocular cystic nephroma is nephrectomy and this proved curative in all three cases. The correct pre-operative diagnosis was made in two out of the three cases because of the characteristic ultrasound appearances. In the first patient, the typical urographic and ultrasound features were present but their signifi- cance was not wholly appreciated as multilocular cystic nephroma had not been seen previously in the depart- ment concerned. It is helpful to suggest the diagnosis before operation and thus avoid the unnecessary use of cytotoxic agents.

Acknowledgements. We are grateful to Miss Irving, Professor Lister and Mr Cudmore for access to the case notes and to Dr Galloway who did the ultrasound in Patient 3.

REFERENCES

Akhtar, N & Qadeer, A (1980). Multilocular cyst of kidney with embryonic tissue. Urology, 16, 90-94.

Banner, MP, Pollack, HM, Chatten, J & Witzleben, C (1981). Multi- locular renal cysts: radiologic-pathologic correlation. American Journal of Roentgenology, 136, 239-247.

Edmunds, W (1892). Cystic adenoma of the kidney. Lancet, i, 801. Madewell, JE, Goldman, SM, Davis, CJ, Hardman, DS, Fcigin, DS &

Lichtenstein, JE (1983). Multilocular cystic nephroma: A radio- graphic pathologic correlation of 58 patients. Radiology, 146,309- 321.

Stuck, KJ, Koff, SA &Silvcr, TM (1982). Ultrasonic features of multicystic dysplastic kidney: expanded diagnostic criteria. Radio- logy, 146, 217-221.

Wood, BP, Muurahainen, N, Anderson, VM & Ettingen, JJ (1982). Multicystic nephroblastoma: ultrasonic diagnosis (with a pathologic-anatomic commentary). Paediatric Radiology, 12, 43-47.