Nephroblastomatosis and Wilms' tumor. Clinical experience and management of seven patients

Hyperplastic perilobar nephroblastomatosis: long-term survival of 52 patients

BACKGROUND

This study provides insight into the clinical behavior, diagnostic complexities, and long-term management of patients with hyperplastic perilobar nephroblastomatosis (HPLN).

PROCEDURE

Fifty-two patients with HPLN with available long-term follow-up were retrospectively analyzed for pathologic, radiologic, and clinical features.

RESULTS

The mean age at diagnosis was 16 months; the lesions were bilateral in 49 patients. Of 33 patients who initially underwent diagnostic biopsy and adjuvant chemotherapy, 18 (55%) developed Wilms tumor (WT) at a mean of 35 months from diagnosis. Of 16 patients whose initial therapy included nephrectomy and adjuvant therapy, three (19%) developed WT at a mean of 36 months from diagnosis. All three patients who underwent initial diagnostic biopsy and received no adjuvant therapy during their initial course developed WT 4, 4, and 10 months following diagnosis. 24/52 patients developed either a single (13 patients) or multiple (11 patients) WT throughout their course; 8/24 (33%) of WT were anaplastic. The time from initial diagnosis to the development of the last WT ranged from 13 to 116 months (mean 42 months). Three children with HPLN died of WT at 3, 5, and 6 years of age; 2/3 were anaplastic.

CONCLUSIONS

HPLN is a self-limited, pre-neoplastic proliferative process associated with a high risk of developing WT. The accurate diagnosis and the choices of therapy during the often-complex course of HPLN depend on the availability and accurate interpretation of a combination of pathologic, radiologic, and clinical information. When such information is appropriately obtained, the long-term survival of patients with HPLN is excellent.

Repeated surgical excision for an unusual variant of nephroblastoma: case report and review of the literature

Bilateral fetal rhabdomyomatous nephroblastoma is a rare variant of Wilms' Tumor. The authors report the evolution over 48 months of a 10-month-old baby with bilateral nephroblastoma for which a left nephrectomy was initially performed. A right kidney tumor was enucleated preserving the kidney. The transformation of the primary tumor into a completely differentiated cystic nephroblastoma or nephromalike tumor and the appearance of a metachronous lesion was seen. This report emphasizes the role of nephron-sparing surgery in bilateral Wilms' Tumor when a benign transformation occurs under chemotherapy.

Does nephroblastomatosis influence the natural history and relapse rate in Wilms' tumour? A single centre experience over 11 years

The presence of multifocal or diffuse nephrogenic rests (NRs) in one or both kidneys is termed nephroblastomatosis (Nbm). Nbm may be a predisposing factor for Wilms' tumour (WT). The aim of this retrospective study was to evaluate the impact of Nbm on the outcome of WT in children. We assessed the outcome of 81 children with Wilms tumours and practical implications of Nbm in the treatment and follow-up. All the pathology slides have been reviewed in 1997. 63 had WT without Nbm (group A) and 18 had WT associated with Nbm (group B). There was no statistical difference between the two groups according to the age at diagnosis and histology. Clinical abnormalities were more frequent in group B (33 versus 8%). There was no statistical difference between the percentage of stage IV in both groups, but bilaterality (stage V) was present only in the group B. Relapse was observed in 20/81 patients (25%): 11 (17%) in group A and 9 (50%) in group B. Mean delay of relapse was longer (25 months) in group B than in group A (10 months). For the whole population, with a median follow-up of 9 years, the event-free survival (EFS) and the overall survival (OS) probabilities were respectively 74%+/-10 and 83%+/-9 at 120 months. The difference in EFS between groups A (82+/-9%) and B (38%+/-29) was significant (P=0.004). The discovery of Nbm in the non-tumoral part of the kidney with WT can be an adverse factor and in particular favours the subsequent development of a new Wilms tumour. It justifies separate follow-up guidelines.

[Unusual presentation of nephroblastomatosis]

BACKGROUND

Nephrogenic rests generally constitute precursor lesions of Wilms' tumor. We report a case of right nephroblastomatosis with dysmorphic features.

CASE REPORT

An enlargement of the right kidney was incidentally discovered in a 1-year-old girl with dysmorphic features but normal psychomotor development. Combined ultrasonography and computerized tomography (CT) scan showed right cortical nephroblastomatosis. Chemotherapy using actinomycin D and vincristin was successful; however, an hyperechogenic nodule was subsequently found, necessitating a right nephrectomy.

CONCLUSION

The relationship between nephroblastomatosis and Wilms' tumor is discussed. This case report reminds us of the importance of a long-term follow-up including echography and CT scan in cases of nephroblastomatosis.

Perlman and Wiedemann-Beckwith syndromes: two distinct conditions associated with Wilms' tumour

Though children with Perlman and Wiedemann-Beckwith syndromes have a number of features in common, the two conditions are probably separate entities. The distinction may not always be easy, however, partly because of the extreme rarity of Perlman syndrome, only nine cases of which have been reported so far. We report two siblings, initially diagnosed as having Wiedemann-Beckwith syndrome, in whom the correct diagnosis of Perlman syndrome was made only after an autopsy on the second child. By comparing and contrasting the features of Perlman and Wiedemann-Beckwith syndromes in this report we hope to make it easier to distinguish the two conditions.

Nephroblastomatosis: the whole spectrum of abnormalities in one case

A case of nephroblastomatosis is described in a previously healthy child with a palpable mass in the right upper quadrant as an incidental finding. This case of nephroblastomatosis demonstrates the whole spectrum of abnormalities from local regression to formation of true Wilms' tumors bilaterally over a 4-year period. The evolution of these changes provides a graphic and dramatic example of this interesting entity, indicating its potential malignant association with Wilms' tumor.

A mouse model of the aniridia-Wilms tumor deletion syndrome

Deletion of chromosome 11p13 in humans produces the WAGR syndrome, consisting of aniridia (an absence or malformation of the iris), Wilms tumor (nephroblastoma), genitourinary malformations, and mental retardation. An interspecies backcross between Mus musculus/domesticus and Mus spretus was made in order to map the homologous chromosomal region in the mouse genome and to define an animal model of this syndrome. Nine evolutionarily conserved DNA clones from proximal human 11p were localized on mouse chromosome 2 near Small-eyes (Sey), a semidominant mutation that is phenotypically similar to aniridia. Analysis of Dickie's Small-eye (SeyDey), a poorly viable allele that has pleiotropic effects, revealed the deletion of three clones, f3, f8, and k13, which encompass the aniridia (AN2) and Wilms tumor susceptibility genes in man. Unlike their human counterparts, SeyDey/+ mice do not develop nephroblastomas. These findings suggest that the Small-eye defect is genetically equivalent to human aniridia, but that loss of the murine homolog of the Wilms tumor gene is not sufficient for tumor initiation. A comparison among Sey alleles suggests that the AN2 gene product is required for induction of the lens and nasal placodes.

The nephroblastomatosis complex and its relationship to Wilms' tumor

Nephroblastomatosis (NB), a persistence of abnormal embryonal renal tissue beyond 36 weeks' gestation, is often associated with Wilms' tumor. The exact relationship of NB to the development of Wilms' tumor is unclear. Four cases are presented that elucidate the entire morphological spectrum of this disease. Analyses of these cases suggest these conclusions: (1) the NB complex is a spectrum of lesions from benign multifocal nodular renal blastema, resembling residual nephrogenic zones of immature fetal kidney, to Wilms' tumor; (2) infantile NB is a premalignant variant of Wilms' tumor with a favorable outcome usually, when treated early; (3) neonatal nephromegaly requires a complete evaluation and follow-up imaging; persistence mandates biopsy; (4) "second-look" laparotomy is unnecessary with state-of-the-art imaging; and (5) standardization of terminology is essential.

Nephrogenic rests, nephroblastomatosis, and the pathogenesis of Wilms' tumor

A new classification and terminology is proposed for precursor lesions of Wilms' tumor (WT), based upon morphology and natural history. The generic term nephrogenic rest (NR) is used for all WT precursors. Two major categories of NR are recognized: perilobar (PLNR) and intralobar (ILNR). Nephroblastomatosis signifies the presence of multiple or diffuse NRs. Nephroblastomatosis can be classified into four categories: (a) perilobar (PLNR only); (b) intralobar (ILNR only; (c) combined (PLNR and ILNR); and (d) universal. The individual rests can be subdivided into (a) nascent or dormant NRs; (b) maturing or sclerosing NRs; (c) hyperplastic NRs; and (d) neoplastic NRs. Of 282 evaluable unilateral WT specimens, 28.4% were definitely rest-positive, and an additional 12.4% were probably positive, with equal prevalence of PLNRs and ILNRs. Median age at diagnosis of WT was 36 months with PLNRs, 16 months with ILNRs, and 12 months if both types were present. PLNRs were strongly associated with synchronous bilateral WTs, and ILNRs with metachronous contralateral WTs. ILNRs were associated with aniridia and Drash syndrome, whereas PLNRs were more commonly found with hemihypertrophy and/or Beckwith-Wiedemann syndrome. The delineation of two distinct categories of WT precursors suggests pathogenetic heterogeneity for WTs. The biological and clinical implications of NRs are considered in the context of this classification.

Surgical treatment of bilateral Wilms' tumours with special reference to second operations in metachronous disease

We report on six patients with bilateral Wilms' tumours (among them one pair of siblings) who underwent surgery within a period of 20 years. Wilms' tumours appeared synchronously in three patients and successively in the other three. Case reports are given for three of the six patients. The tumours have a remarkable multilocular appearance, indicating a multilocular genesis. In this context, the phenomenon of nephroblastomatosis is discussed. In addition to surgical treatment, aggressive conservative therapy should be employed, particularly with metachronous disease and the resulting acquired solitary kidney in these patients.

Adult nephroblastoma

Clinical, pathologic, and ultrastructural features of two cases of adult nephroblastoma (Wilms' tumor) are presented, one in a 77-year-old man who had a large tumor with extracapsular extension and blood vessel invasion. Histologically, it consisted mainly of blastema. The patient died during the first course of postoperative chemotherapy with dactinomycin. The second patient was a 47-year-old woman with a tumor limited to the renal parenchyma. Histologically, the tumor was mainly epithelial. This tumor was discovered incidentally and remained unchanged for 5 years before surgery. The patient underwent nephrectomy and refused further treatment. She was free of disease 2 years after surgery.

Bilateral Wilms tumor

Despite institutional variation in the treatment of synchronous bilateral Wilms tumor, a 76 per cent over-all 3-year survival rate has been achieved. We reviewed 145 patients with stage V disease (synchronous bilateral Wilms tumor) registered with National Wilms Tumor Studies 2 and 3. The majority of the patients (94, or 65 per cent) underwent initial surgical resection followed by chemotherapy with or without radiation, with a 3-year survival rate of 82 per cent. However, survival of 45 patients who underwent initial biopsy, postoperative chemotherapy and second-look surgery was 57 per cent at 3 years, a result not significantly different statistically from the 82 per cent figure. Only 38 per cent of the patients had all tumor resected at 1 or more operations. Therefore, emphasis is being placed on chemotherapy as the predominant treatment modality for this disease. Unfavorable histology was found in 10 per cent of the patients and 6 patients (4 per cent) had discordant histology, that is unfavorable histology on 1 side with contralateral favorable histology. Better prognostic factors were patient age less than 3 years at diagnosis, lower stage of the most advanced lesions, favorable histology and negative nodal involvement. Currently, routine bilateral biopsy of tumors is recommended, followed by chemotherapy according to the stage of the most advanced lesion. Impressive shrinkage of tumor can be expected with the hope that surgery will allow renal preservation (excisional biopsy or partial nephrectomy) rather than nephrectomy.

Advances in the care of the child with cancer. The importance of histologic subclassification of tumors

The importance of histologic subclassification of tumors lies principally in the correlation between nosology and tumor biology, including response to therapy. Subclassifications that are practically achieved, reproducible and uniquely predictive are of great value. As new methods are engaged and new clinical data are reported, classifications may be changed. Subclassifications of solid tumors with proven therapeutic application are exemplified by renal tumors and lymphomas that are commonly referred to as "favorable" or "unfavorable histology." Subclassification of soft tissue sarcomas, neuroblastoma and tumors of the central nervous system are being investigated, but are presently of undetermined relevance. Classifications and subclassifications of solid tumors of children are presented in the context of prognostic relevance.

An analysis of histology and DNA-ploidy in primary wilms tumors and their metastases and a study of the morphological effects of therapy

In children with Wilms' tumours the length of survival is greatly influenced by success in preventing or controlling metastatic disease. The current study focuses on the morphological aspects of metastases when compared with the primary tumour. In 8 patients it appeared that blastema is the most likely component to metastasize, whereas epithelial and stromal components were hardly, if at all, represented in metastases. Furthermore, flow cytometric DNA ploidy determinations on 4 cases showed that both the primary tumours and the metastases had stemlines in the diploid and low aneuploid (hyperdiploid) range. Finally, in four cases the influence of therapy on morphology of the primary tumours was analyzed. In these cases blastema seemed to be the component most sensitive to therapy. Thus, blastema seems to play a central role in prognosis of Wilms' tumours; either reacting to therapy or, if insensitive, by metastasizing.