Case 4: 7-‐year-‐old boy [Chief complaint] Gross Hematuria [History of present illness] He visited an urological clinic because of gross hematuria from one day before the consulta?on. A renal tumor with intratumoral hemorrhage in the leC kidney was suspected, and he was referred to our hospital for further examina?on and treatment. [Past medical history] Not par?cular
[Laboratory data] WBC 6.2×103/μl, RBC 4.48×106/μl, HGB 11.9mg/dl↓, PLT 22.2×104/μl, TP 6.8g/dl, Alb 3.8g/dl↓, T.bil 0.6mg/dl, ChE 305U/L, AST 27U/l, ALT 11U/l, LD 270U/l↑, ALP 399U/l↑, Na 138mmol/L↓, K 3.9mmol/l, CL 102mmol/l, BUN 9mg/dl, Crea?nine 0.33mg/dl↓, Ca 9.1mg/dl, CRP 4.51mg/dl↑ [Urinalysis] Uric blood +3, Uric protein ±, RBC 87.7/HPF, WBC 5.9/HPF →He was suspected of urinary tract infec?on by the laboratory studies and urinalysis performed at the first visit in our hospital.
Image presenta?on ※CT ※MRI ※99mTc-‐DMSA renal scin?graphy
◆The abdominal CT shows three mul?locular cys?c masses in the leC kidney.
◆The content of the cyst is slightly higher adenua?on than that of water in the unenhanced CT.
◆These cys?c masses have enhancing septa and no solid components.
[The abdominal CT] [Unenhanced CT] [The enhanced CT]
◆The enhanced CT shows slightly low adenuated area (→) in the renal parenchyma around these cys?c masses.
◆However, a part of these cys?c masses appear to communicate with the renal pelvis ( →).
The enhanced CT (Coronal image) ◆The hydronephrosis is not evident in the leC kidney.
Fat suppressionT1WI [Unenhanced images] [Enhanced images] [T2WI]
◆MRI shows three mul?locular cys?c masses with hyperintense on T2WI in the leC kidney, which have no solid component. ◆The hyperintense cysts on unenhanced fat suppression T1-‐WI (→) are seen within these masses.
[MRI]
◆The hyperintense cysts on unenhanced fat suppression T1WI shows hyperintesity on b=1000 s/mm2 diffusion weighted image (→) and have lower ADC values than the hypointense cysts on unenhanced fat suppression T1-‐WI, which may indicate hemorrhage.
[99mTc-‐DMSA renal scin?graphy]
◆Renal scin?graphy shows enlarged leC kidney and some defects corresponding to these masses.
[Summary of imaging findings]
◆Abdominal CT and MRI shows three mul?locular cys?c masses with contrast-‐enhancement septa and hemorrhage in the leC kidney. ◆Renal scin?graphy shows enlarged leC kidney and some defects corresponding to these masses. ◆The enhanced CT and MRI show slightly low enhanced areas in the renal parenchyma which were located around these cys?c masses.
[The differen?al diagnosis] ◆The differen?al diagnosis was cys?c tumors occurring mainly in children. ・Multilocular cystic nephroma (MLCN) ・Cystic Wilms tumor ・Cys?c par?ally differen?ated nephroblastoma (CPDN) ・Segmental mul?cys?c dysplas?c kidney (MCDK)
◆A leC nephrectomy was performed with the pre-‐diagnosis of mul?locular cys?c nephroma.
◆Gross specimen shows well-‐circumscribed tumor with mul?ple cysts (→).
◆Histopathological examina?on shows mul?ple noncommunica?ng cysts lined by fladened or cuboidal epithelium. ◆These masses do not communicate with the renal pelvis.
HE stain
◆The cyst epithelial cells are posi?ve for CKae1/ae3 but nega?ve for ER and CD10.
[The final histopathological diagnosis] Multilocular cystic nephroma (MLCN) Pediatric cys?c nephroma -‐WHO classifica?on 2016: tumors of the kidney
WHO classifica?on of tumors of the kidney ◆Nephroblas?c and cys?c tumors occurring mainly in children
Nephrogenic rests Nephroblastoma CPDN Pediatric cys?c nephroma equivalent of MLCN
◆Mixed epithelial and stromal tumor family Adult cys?c nephroma Mixed epithelial and stromal tumor
2016 4th edi?on
※Adult cys?c nephroma is now thought to belong to the mixed epithelial and stromal tumor family and to be unrelated to pediatric cys?c nephroma.
[Pediatric cys?c nephroma] ◆Defini?on: ・Mul?locular, exclusively cys?c neoplasm of very young children. ・The septa contain only fibrous ?ssue and differen?ated tubules.
◆Epidemiology: ・Occurrence more commonly in boys than in girls. ・Most pa?ents are younger than 24 months old. ・No specific symptoms (flank pain, urinary infec?on, hematuria). ・Associa?on with DICER1 muta?ons.
◆Radiological features: ・Large mul?locular cys?c mass with varying size cysts, thin septa and no solid components. ・Cysts are non communica?ng with each other. ・Calcifica?on and hemorrhage are rarely observed.
2012年 放射線科認定医試験に出題
◆The differen?al diagnosis of pediatric nephroma ・CPDN ・Cys?c wilms tumor
・The presence of solid components and thick septa supports the diagnosis of CPDN or wilms tumor. However, clearly dis?nc?on between pediatric cys?c nephroma and these tumor is difficult. ・The presence of immature nephroblas?c elements excludes diagnosis of pediatric cys?c nephroma and indicates CPDN or cys?c wilms tumor in the histopathology examina?on.
[Correct answer] Multilocular cystic nephroma (MLCN) Pediatric cys?c nephroma -‐WHO classifica?on 2016: tumors of the kidney
References 1. Stama?ou K et al. Cys?c nephroma: a case report and review of the literature. Cases J, 1(1): 267, 2008 2. Wani B et al. Asymptoma?c infan?le cys?c nephroma: a diagnos?c dilemma. Indian J Surg, 74(6): 501-‐3, 2012 3. Dong B et al. Mul?locular cys?c nephroma treated with laparoscopic nephron-‐sparing surgery: A case report. Can Urol Assoc J, 8(7-‐8): E545-‐7, 2014 4. Ozturk H et al. Uretherial invagina?on of mul?locular cys?c nephroma; a case report of a new pathologic variant. Int J Clin Exp Pathol, 17; 7(8): 5271-‐9, 2014 5. Dell’Aq L. An Unusual presenta?on of cys?c nephroma in an adult man. Rare Tumors, 18; 7(2): 5860, 2015 6. Deger AN et al. Adult mul?cys?c nephroma: case report and review of the literature. J Clin Diagn Res, 9(8): ED22-‐3, 2015 7. M. Fujita et al, An unusual case of cys?c nephroma protruding into the renal pelvis. Hinyokika Kiyo. 56(10): 577-‐80, 2010 8. M. Shiramizu et al, Mul?locular cys?c nephroma treated by enuclea?on. Nihon Hinyokika Gakkai Zasshi, 78(8): 1429-‐34, 1987 9. WHO classifica?on 2016: tumors of the kidney.