PEDIATRIC UROLOGIC ONCOLOGY 0094-0143/00 $15.00 + .OO

NON-WILMS’ RENAL TUMORS IN CHILDREN

Bruce Broecker, MD

Renal tumors other than Wilms’ tumor are tastases occur in 40% to 60% of patients with infrequent in childhood. Wilms’ tumors ac- clear cell sarcoma of the kidney, whereas they count for 6% to 7% of childhood cancer, are found in less than 2% of patients with whereas the remaining renal tumors account Wilms’ tumor.**,26 This distinct clinical behav- for less than l%.27The most common non- ior is one of the features that has led to its Wilms‘ tumors are clear cell sarcoma of the designation as a separate tumor. Other clini- kidney, rhabdoid tumor of the kidney (both cal features include a lack of association with formerly considered unfavorable Wilms’ tu- sporadic aniridia or hemihypertrophy. mor variants but now considered separate tu- Clear cell sarcoma of the kidney has not mors), renal cell carcinoma, mesoblastic been reported to occur bilaterally and is not nephroma, and multilocular cystic nephroma. associated with nephroblastomatosis. It has Collectively, these tumors account for less been reported in infancy and adulthood, but than 10% of the primary renal neoplasms in the peak incidence is between 3 and 5 years childhood. of age. It has an aggressive behavior that responds poorly to treatment with vincristine and actinomycin alone, leading to its original CLEAR CELL SARCOMA designation by Beckwith as an unfavorable histology pattern. The addition of doxorubi- Clear cell sarcoma of the kidney is cur- cin in aggressive chemotherapy regimens has rently considered a separate tumor distinct improved outcome. Current 4year survival is from Wilms’ tumor, although in early Na- 75% in a group of 50 patients in NWTS-III.17 tional Wilms’ Tumor Studies (NWTS) and In- In the ongoing NWTS-V protocols, clear cell ternational Society of Pediatric Oncology sarcoma of the kidney at all stages is treated (SIOP) studies, it was considered an unfavor- with the same regimen used for Wilms’ tumor able histology pattern of Wilms’ tumor (Table with diffuse anaplasia (excluding stage I), 1): In these early NWTS series, 4% of regis- that is, radical nephrectomy followed by che- tered renal tumors were designated clear cell motherapy with cyclophosphamide, etopo- sarcoma.S,’8 The tumor was first described as side, vincristine, and doxorubicin for 24 a distinct entity in 1978 by three independent weeks and radiotherapy. groups, Beckwith and Palmer,5 Morgan and Kidd,“ and Marsden and co-worker~,~~who RHABDOID TUMOR OF THE KIDNEY labeled it “bone metastasizing renal tumor of childhood” in recognition of its well-known As is true for clear cell sarcoma, rhabdoid propensity for skeletal metastasis. Bone me- tumor of the kidney was formerly categorized

From the Section of Pediatric Urology, Children’s Hospital of Atlanta and the Department of Urology, Emory University School of Medicine, Atlanta, Georgia

UROLOGIC CLINICS OF NORTH AMERICA

’ VOLUME 27 NUMBER 3 * AUGUST 2000 463 ! 464 BROECKER

Table 1. SUMMARY OF CHARACTERISTICS OF NON-WILMS’ RENAL TUMORS OF CHILDREN

Renal Cell Congenital Myoblastic Characteristic Clear Cell Sarcoma Rhabdoid Tumor Carcinoma Nephroma CNICPDN Median age 4 Years 11 Months 12 Years <3 Months 1-2 Years Malignant potential Yes Yes Yes Cellular variant Risk of local potentially malignant recurrence if (rare) tumor spill Follow-up/ Aggressive Aggressive ? Immunotherapy Usually none Usually none adjuvant therapy chemotherapy and chemotherapy for metastatic Consider chemo- Obtain follow- radiotherapy and radiotherapy disease therapy for cellular up imaging variant if intra- operative tumor spill Unique Bone metastases in Associated with Infiltrates renal characteristics 50% medulloblastoma parenchyma Propensity for brain metastases Prognosis 75% Survival 20% Survival Good for localized Excellent Excellent disease Poor for metastatic disease

CN = cystic nephroma; CPDN = cystic partially differentiated nephroblastoma. as an unfavorable histologic pattern of Wilms’ ity is 80%.61 Even patients with completely tumor but is now considered a separate tu- resected tumors with negative lymph nodes mor? It is rare, accounting for 2% of the renal have a 50% mortality rate. The current treat- tumors registered with NWTS. It may arise ment protocol in NWTS-V is radical ne- in extrarenal locations, although controversy phrectomy followed by chemotherapy with remains regarding the exact identity of these carboplatinum, etoposide, and cyclophospha- extrarenal rhabdoid tumors.& Haas and co- mide for 24 weeks and radiothyapy. workers2Rgave the tumor its present name and suggested its separate identity in 1981, but it was first described by Beckwith and RENAL CELL CARCINOMA Palmer in 1978 and referred to as a rhabdo- myosarcomatoid neoplasm, reflecting the Renal cell carcinoma is the most common presence of cells with a rhabdomyoblast ap- renal neoplasm in adults and occurs rarely in pearan~e.~On immunohistochemical staining, the pediatric patient. Approximately 1% to this resemblance appears to be deceiving, and 2% of renal cell carcinomas occur in patients evidence of a myogenic lineage is generally aged less than 21 years, and these lesions not found.62A diversity of phenotypic mark- account for 2% to 5% of primary renal tumors ers are expressed, but the most common and in this age group. The earliest well-docu- consistent are vimentin and cytokeratin. mented cases in the English language were Current thought is that rhabdoid tumor of reported by Boyd and Lisa12 and McCurdy41 the kidney is probably neurogenic in origin. in 1934. By 1960, more than 50 occurrences The tumor is typically large and central/ hilar had been published as case reports. The first in origin, often replacing the entire kidney. It series of patients with renal cell carcinoma presents early in life, with more than 50% of was reported by Dehner and co-workersZ1 patients aged less than 1 year. The median from the Armed Forces Institute of Pathology age is 11 months.6’ Metastases may be found (15 patients) in 1970. The two largest series in not only in the lungs and liver (as is true for the literature are 20 patients collected from Wilms’ tumor) but also in the brain (unlike four institutions reported on by Raney and Wilms’ tumor). In addition to brain metasta- co-~orkers~~in 1983 and 22 patients from the ses, primary brain tumors have been reported Memorial Sloan-Kettering Cancer Center re- to occur in 10% to 15% of patients, the most ported on by Aronson and co-workers2 in common being medulloblastoma.ll,61 1996. Rhabdoid tumor of the kidney is an aggres- Renal cell carcinoma has been reported in sive lesion with a poor prognosis. Most pa- infancy, but most .patients are older, with a tients present with advanced stage disease, mean age of 9 to 15 years. During the second the tumor responds poorly to current chemo- decade of life (age 10 to 20 years), patients therapy and radiotherapy, and overall mortal- presenting with a primary intrarenal tumor QON-WILMS’ RENAL TUMORS IN CHILDREN 465 are equally likely to have a Wilms’ tumor or of 48 patients was reported in 1973. Clinico- renal cell carcinoma.29Although one of the pathologic features included its occurrence in patients with renal cell carcinoma reported on the neonatal period as an unencapsulated and in the series by Hartman and ~olleagues~~hadlocally invasive fibrous lesion that could be bilateral tumors, that feature is uncommon cured by nephrectomy alone (“no cases of for this tumor. tumor recurrence by metastasis having been It has been debated whether pediatric renal documented”).l0Local recurrence as a result cell carcinoma is a different tumor than its of incomplete resection could occur. In subse- adult counterpart. Caraco and co-~orkers’~ quent cases, patients with documented metas- studied 16 pediatric patients from three chil- tasis and a malignant course have been re- dren‘s hospitals in Canada and reported a ported, and the histology of the tumors in higher incidence of papillary histology than these patients has been shown to contain seen in adult renal cell carcinoma and, per- atypical cellular features and a high mitotic haps more persuasively, cytogenetic translo- index.- cations involving the X chromosome, which The relationship of congenital mesoblastic are rarely seem in adult tumors, in two of nephroma to Wilms’ tumor continues to be four patients with tumor karyotyping. The debated. It has been reported in a patient clinical behavior of pediatric renal cell carci- with Beckwith-Wiedemann syndrome who noma and adult tumor is similar; neverthe- was noted to have cytogenetic rearrange- less, that is, the most significant prognostic ments at chromosome 11~15,and adjacent variable for survival is complete resection and normal renal tissue that may contain subcap- low-stage disease.2,49 Survival for patients sular tumorlets, supporting the association presenting with stage I disease is greater than with Wilms’ tumor.5oOther investigators have 90%, for patients with stage I1 and 111 disease noted that the cellular variant of congenital approximately 50%, and for patients with mesoblastic nephroma may metastasize to stage IV disease almost 0%. The tumor is not bone and brain and has histologic features responsive to radiotherapy, and there is no more reminiscent of clear cell sarcoma of the effective chemotherapy for nonlocalized or kidney, stressing the latter tumor as a more relapsed disease, although MacArthur and probable association.54 co-worker~~~reported a complete response to Hypertension may occur and may be recombinant interleukin-2 in one child pres- caused by entrapment of renal parenchyma enting with metastatic renal cell carcinoma. by invading fibrous strands at the edge of the Renal cell carcinoma has been reported in tumor and the resultant renin hypersecre- children with tuberous sclerosis5*,63 (also seen tion.16 Hypercalcemia also has been reported in adults), Beckwith-Wiedemann owing to tumor secretion of pr0staglandin.5~ and von Hippel-Lindau syndrome,@and aris- Nephrectomy alone seems to be adequate ing in a multicystic kidney.’ treatment for infants less than 3 months of age and perhaps even older patients with typ- ical fibrous histology and complete tumor re- CONGENITAL MESOBLASTIC section.3l Chemotherapy with a Wilms’ tumor NEPHROMA regimen should be considered for patients with incomplete resection, cellular features, Congenital mesoblastic nephroma occurs in and a high mitotic index, and certainly for two forms-a typical or fibromatous type any patient with evidence of metastasis or seen almost exclusively in infants under the recurrence. Partial nephrectomy buld not age of 3 months that is benign and a second be performed because the risk of local recur- atypical or cellular variety usually seen in rence would be high owing to the tumor’s older children but also occurring in infants tendency to infiltrate surrounding renal pa- that is potentially malignant and capable of renchyma. recurrence and meta~tasis.~~Congenital meso- blastic nephroma is the most common solid renal tumor of the newborn period. Bolande MULTILOCULAR CYSTIC and co-worker~~first described the tumor as NEPHROMA a separate entity in 1967, reporting eight cases in which evidence supported its categoriza- A multilocular cyst in a child presents as a tion as a true neoplasm, albeit benign, that lesion that may range from a benign multiloc- was related to Wilms’ tumor. A larger series ular cyst to a multilocular cyst with partially 466 BROECKER differentiated Wilms’ tumor to a cystic Wilms’ amount in which triphasic Wilms’ tumor is tumor. The first two entities are synonymous seen. There also must be epithelial lined cysts with the terms cystic nephroma and cystic par- with clear serous fluid in distinction to cystic tially diferentiated nephroblastorna, respectively. areas of hemorrhage or necrosis wihan These lesions are tumors representing neo- otherwise solid tumor for the lesion to be plastic change rather than developmental considered a cystic Wilms’ tumor. dysplastic change. The treatment of multilocular cysts and EdmundsZ3is credited with the first pub- multilocular cysts with partially differenti- lished description of a multilocular cyst, re- ated Wilms’ tumor is nephrectomy alone. porting a cystic adenoma of the ludney in Multilocular cysts are benign tumors. Recur- 1892. Powell and co-workers@ outlined the rences or metastases have not been reported. generally recognized criteria for diagnosis of Multilocular cysts with partially differenti- a multilocular cyst of the kidney in 1951: (1) ated Wilms’ tumor have been reported to re- unilateral involvement, (2) a solitary lesion, cur locally; metastases have not been re- (3) a multilocular lesion, (4) no communica- p0rted.3~Cystic Wilms’ tumor is a malignant tion between individual cysts, (5) no commu- tumor, although seemingly less aggressive nication between cysts and the renal pelvis, than the more common solid Wilms’ tumor. (6) cysts lined by epithelium, (7) no normal These tumors should be treated as any other nephrons in the septa separating cysts, and Wilms’ tumor, with the appropriate protocol (8) remaining normal renal parenchyma. for the particular stage. These criteria have been modified slightly by Joshi and BeckwithJ3CNin a more recent publi- cation that stressed that, in a multilocular cyst, the only solid tissue present is the thin ANGIOMYOLIPOMA septa dividing the individual cysts. These septa conform to the spherical shape of the Angiomyolipoma is a well-recognized be- cysts and may contain mature renal tubules nign renal tumor occurring most commonly although not fully developed nephrons. The in adults. It occurs in a sporadic form and in cysts may range in diameter from a few milli- association with the tuberous sclerosis com- meters to many centimeters. The fluid con- plex, an entity involving mental retardation, tained within the cysts is clear, with a chemi- epilepsy, glial nodules in the brain, adenoma cal content similar to serum. Typically, sebaceum, phakoma of the retina, and hamar- cytology of this fluid is normal. tomas of the liver, heart, bone, or kidney. Multilocular cysts occur in children and Approximately 80% of patients with tuber- adults. In a review in 1991 of 187 previously ous sclerosis have an angiomyolipoma of the reported cases. Castillo and co-w~rkers’~ kidney.44Angiomyolipoma of the kidney oc- noted that 80% of children were between the curring in childhood is almost always associ- ages of 3 and 24 months with 65% of these ated with the tuberous sclerosis complex.44 patients being male. Eighty-five percent of the Tumors are frequently bilateral and multifo- adults were over 40 years of age, with 76% cal. Although benign in histologic appearance of these patients being female.14 Castillo and and behavior (except for hemorrhage), they colleagues also reported seven bilateral cases, may extend into the renal vein, inferior vena in variance from earlier criteria set by Powell. cava, and right atrium and involve local The distinction between multdocular cysts lymph nodes?, 36, 53, 57 Hemorrhage is the most and multilocular cysts with partially differen- common complication. Its occurrence seems tiated Wilms’ tumor, which are indistinguish- primarily related to size, with angiomyolipo- able radiographically and grossly is the hsto- mas less than 4 cm in diameter having a logic content of the septa. The septa of low risk and lesions over 4 cm having an multilocular cysts are composed of fibrous increasingly greater risk.22 45, 56 Management tissue in which mature tubules may be pres- should be nonoperative, with periodic re-im- ent, whereas the septa of multilocular cysts aging for small asymptomatic lesions. Lesions with partially differentiated Wilms’ tumor that have bled and lesions greater than 4 cm have blastema with or without other embry- may require surgical management. Partial ne- onic stromal or epithelial cells. Cystic Wilms’ phrectomy if possible, rather than total ne- tumor differs from the previous two lesions phrectomy is the preferred surgical manage- in that, radiographically and grossly, there are ment. Angioinfarction of amenable tumors is solid portions of the tumor varying in also an option. NON-WILMS’ RENAL TUMORS IN CHILDREN 467

MISCELLANEOUS TUMORS OF THE Two cases of a tumor termed ossifying tumor KIDNEY of the infuntile kidney have been reported by Chatten and co-~orkers.’~Characterized pre- In addition to the uncommon tumors dis- dictably by occurrence in infancy and abun- cussed previously, several additional tumors dant bone and osteoid formation, they have have been reported. In most cases, each of a benign clinical behavior. these tumors is so rare that relatively few Juxtaglomerular cell tumor, also termed re- recommendations can be made regarding ninornu, is a benign renin-producing tumor their natural history and optimal treatment. seen most commonly in adolescents or young Included in this group are several neural adults.’ It is typically a small lesion several tumors-primitive neuroectodermal tumor, centimeters in size but capable of producing primary renal neuroblastoma, carcinoid, impressive clinical symptoms of malignant schwannoma, and paraganglioma. hypertension and hypokalemia (owing to hy- Primitive neuroectodermal tumors occur peraldosteronism). Excision is curative. most commonly in the chest and extremities, Intrarenal teratoma has been reported in a but 31 occurring within the kidney have been child but must be distinguished from the reported on by Roloson and Be~kwith~~in more common teratoid Wilms’ tumor by the the NWTS pathology archives. These lesions presence of recognizable nonrenal organs or resemble Wilms’ tumor grossly and radio- tissue, such as brain, skin, or gastrointestinal graphically and may be confused with blaste- tract? ma1 Wilms’ tumor microscopically. They oc- Transitional cell carcinoma of the renal cur in adults and children and have an pelvis can also occur, generally as a low-grade aggressive behavior. papillary lesion.35,58 Various sarcomas arising Neuroblastoma has been reported as a pri- in the kidney, including leiomyosarcoma, fi- mary renal tumor, arising within the renal broxanthosarcoma, and rhabdomyosarcoma parenchyma; however, a more common pre- have been reported in children, as has one sentation is renal invasion by an adrenal neu- case of primary melanoma of the renal roblast~ma.~~The behavior and treatment of pelvis.24.26, 32.37.43 renal lesions and of neuroblastoma in other locations are similar. Renal medullary carcinoma is a recently SECONDARY RENAL TUMORS described entity emerging as a distinct tumor from a nebulous group of collecting duct car- Leukemia and lymphoma can metastasize cinomas reported on by Davis and co-work- to the kidney. Lymphoma may occur as a ersZoin 34 patients gleaned from the Armed primary renal tumor as Metastatic tu- Forces Institute of Pathology over 22 years. mors usually infiltrate the kidney diffusely These tumors were found in patients ranging but may also appear as radiographically dis- in age from 11 to 39 years, 11 of whom were crete lesions. Nephredomy is usually not re- under 20 years. All but one of these patients quired if the tumor responds to systemic che- were believed to have sickle cell disease or motherapy. Less commonly, osteogenic sickle cell trait (30 patients) owing to the mi- sarcoma has been reported to metastasize to croscopic finding of drepanocytes, although the kidney in children, as has malignant mel- only 10 carried this clinical diagnosis based an~rna.~ on prior hemoglobin electrophoresis. Renal medullary carcinoma is a highly malignant tumor with metastases present at the time of diagnosis.@There have been no reported References survivors. Nephrogenic adenofibroma is a rare tumor 1. Abbi RK, McVicar M, Teichberg S, et al: Pathologic first reported by Hennigar and Beckwith in characterization of a renin-secreting juxtaglomemlar cell tumor in a child and review of the pediatric 1992.30Five children from the NWTS archives literature. Pediatr Path01 13443-451, 1993 were described with a mean age of 13 years 2. Aronson DC, Medary I, Finlay JL, et al: Renal cell and symptoms of polycythemia and hyper- carcinoma in childhood and adolescence: A retro- tension. Nephrogenic adenofibroma is an un- spective survey for prognostic factors in 22 cases. J Pediatr Surg 31:183-186, 1996 encapsulated but indolent-behaving tumor 3. Aubert J, Casamayou P, Denis P, et al: Intrarenal with no associated metastases. Nephrectomy teratoma in a newborn child. Eur Urol 4306-308, is curative and resolves the symptoms. 1978 468 BROECKER

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