Cystic partially differentiated nephroblastoma in an adult: an immunohistochemical, lectin histochemical and ultrastructural study

Cystic partially differentiated nephroblastoma in a 74-year-old patient

INTRODUCTION

Cystic partially differentiated nephroblastoma is a multilocular cystic variant of Wilms tumor that always presents in children. However, we encountered an elderly patient with cystic partially differentiated nephroblastoma. Therefore, we report it.

CASE PRESENTATION

A 74-year-old male presented with a left renal tumor detected with ultrasonography. Contrast-enhanced computed tomography and magnetic resonance imaging revealed a 4 cm multilocular cystic tumor with septa, which suggested multilocular cystic renal cell carcinoma. Therefore, we performed a radical nephrectomy. The definitive diagnosis of cystic partially differentiated nephroblastoma was made with histopathological findings. After the surgical resection, no recurrence has occurred in the past 13 years.

CONCLUSION

Cystic partially differentiated nephroblastoma can develop in adults, regardless of age. Furthermore, surgical resection can be used as an established treatment option in adult cystic partially differentiated nephroblastoma cases.

Mixed epithelial and stromal tumor of the kidney (MEST) simulating an upper tract TCC

We present a rare and interesting case of a mixed epithelial and stromal tumour (MEST) of the kidney. The case is unique as it involves a male patient with no history of hormonal therapy presenting with a filling defect in the renal collecting system and positive urine cytology. The patient was diagnosed with transitional cell carcinoma of the renal pelvis and subjected to nephroureterectomy, which revealed a solid tumour arising from the lower calyces and extending into the renal pelvis and upper ureter. Pathology revealed a MEST. The patient was disease-free at the 6-month follow-up.

Malignant Nephroblastoma in a Common Marmoset (Callithrix jacchus)

Necropsy of a 17-month-old male common marmoset ( Callithrix jacchus) with a history of increased abdominal girth resulted in the finding of a unilateral polycystic renal neoplasm. Detailed histopathologic and immunohistochemical investigations revealed different tissue types within the tumor including stromal connective tissue and fusiform mesenchymal cell formations surrounding blastemal cells as well as different developmental stages of organ-specific epithelial cells accompanied by extensive cyst formation. Metastases were not observed. In consideration of the macroscopic, histologic, and immunohistochemical findings, the tumor was classified as a nephroblastoma closely resembling the so-called Wilms' tumor, a malignant embryonic renal tumor frequently observed in humans, especially in young children. In contrast, this tumor entity has rarely been observed in nonhuman primates. This report represents the first documented case of a cystic variant of nephroblastoma in a nonhuman primate.

Mixed epithelial and stromal tumour (MEST) of the kidney: report of 14 cases with male and PEComatous variants and proposed histopathogenesis

AIMS

This article adds new cases and variants of MEST with discussion of the histopathogenesis.

METHODS AND RESULTS

Fourteen MEST were originally diagnosed as cystic nephroma which represents an incidence of 1.6% of renal neoplasms in adults. In females, the stromal component showed areas of müllerian differentiation with positive immunoreactivity for oestrogen (ER) and progesterone receptors (PR) and CD10. Immunoreactivity for HMB45 was identified in a single case having a leiomyomatous appearance. The epithelial component displayed features of müllerian epithelium and reactive renal tubular cells. In two male cases, MEST consisted of fibrous and smooth muscle stroma and cysts lined only by reactive renal tubular cells. Immunoreactivity for ER and PR was focal and weak.

CONCLUSIONS

MEST represents a tumour developing from müllerian-like stromal cells in the kidney. The neoplastic stroma encroaches on the renal tubules and has the potential to stimulate the growth of the renal tubules by contact, with development into cysts. Furthermore, the müllerian stroma likely induces the renal tubules to differentiate into müllerian-like epithelium. Melanocytic differentiation of the stroma may occur which represents the PEComatous variant. MESTs in males were histopathologically slightly different from those in females due to the different hormonal milieu.

Mixed epithelial and stromal tumor of the kidney: a case report

The descriptive term "mixed epithelial and stromal tumor of the kidney" was recently proposed for a group of renal tumors characterized histologically by a mixture of stromal and epithelial proliferation. It is a rare benign neoplasm of the kidney which has been reported under various names such as adult type mesoblastic nephroma or others. We report a case of mixed epithelial and stromal tumor in a 47 yr old female patient presenting as a partly cystic and partly solid renal mass. Microscopically, the tumor exhibited spindle cell component in solid portion and epithelial proliferation around microcystic areas. Immunoreactive profiles and ultrastructural examination suggested myofibroblastic nature of the stromal cells. We believe this case exemplifies a unique adult renal tumor displaying both epithelial and stromal neoplastic component and has a few unusual features worthy of attention.

Cystic partially differentiated nephroblastoma

Cystic partially differentiated nephroblastoma is a relatively rare tumour of the kidney usually affecting infants. Cystic Wilms' tumour and multilocular cystic nephroma should be distinguished from cystic partially differentiated nephroblastoma. Multilocular cystic nephroma is a benign tumour whereas cystic Wilms' tumour is at the malignant end of the range of classification of such tumours. Cystic partially differentiated nephroblastoma may undergo local recurrence but there is no report of metastasis.

Extensively Cystic Renal Neoplasms in Adults (Bosniak Classification II or III) – Possible “Common” Histological Diagnoses: Multilocular Cystic Renal Cell Carcinoma, Cystic Nephroma, and Mixed Epithelial and Stromal Tumor of the Kidney

OBJECTIVE(S)

To give an algorithm for resolution of extensively cystic renal neoplasms, preoperatively classified in the Bosniak classification as a category II and III.

METHODS

From 1991 to 6/2004, 701 patients with 727 renal tumours were surgically treated at our hospital. Extensively cystic tumours were found in 10 cases. Extensively cystic tumours were defined as multicystic tumours without any solid nodules visible neither on CT, nor grossly in the specimen at operation (the Bosniak classification type II or III).

RESULTS

Seven multilocular cystic renal cell carcinomas, three mixed epithelial and stromal tumour of the kidney and one cystic nephroma were diagnosed on histology.

CONCLUSION(S)

Extensively cystic renal tumours classified as the Bosniak type II or III correspond histologically to the entities mentioned above (multilocular cystic renal cell carcinoma, cystic nephroma, mixed epithelial and stromal tumour of the kidney). These entities cannot be distinguished one from another on preoperative imaging studies. A preoperative biopsy and intra-operative frozen-section analysis do not lead to a correct diagnosis in many cases. Fortunately, the operative strategy is the same for all these tumours. In such cases, the nephron sparing surgery is indicated, whenever technically feasible, as almost all extensively cystic renal tumours have a good prognosis.

Cystic Nephroma: A Histologic and Immunohistochemical Study of 10 Cases

Context.—Cystic nephroma is a rare and controversial benign multicystic renal tumor. While the clinical, radiologic, and histologic features of cystic nephroma are well described, the immunohistochemical features are not. The role of immunohistochemistry in the differential diagnosis, which includes multicystic renal cell carcinoma, is also unknown.

Objective.—To define the histologic and immunohistochemical features of cystic nephroma.

Design.—Ten cases of cystic nephroma diagnosed at 2 institutions during a period of 10 years were stained with an immunohistochemical panel consisting of 20 immunostains.

Results.—Median age at diagnosis was 61 years, with a range from 31 to 79 years. The female-to-male ratio was 9:1. Grossly, the tumors were multicystic masses without solid nodules. Histologic features included cysts lined by flat, cuboidal, or hobnail epithelium and septa variably lined by fibrous (10/10 cases) and/or ovarian-like (7/10 cases) stroma. Corpus albicans–like acellular hyalinized structures were noted in the septa in 9 of 10 cases. The cyst epithelium showed consistent positivity for distal tubule/collecting duct markers (cytokeratin 19, cytokeratin AE1/AE3, epithelial membrane antigen) and variable positivity for proximal tubule markers (α1-antitrypsin, lysozyme, CD15, CD10). The ovarian-like stroma (present in 7/10 cases) stained positively for progesterone receptors (6/7 cases) and estrogen receptors (4/7 cases).

Conclusions.—Our immunohistochemical findings confirm a previous report of both distal tubule/collecting duct and proximal tubule differentiation in cystic nephroma. Stromal estrogen and/or progesterone receptor positivity in the majority of cases of cystic nephroma is a novel finding.

Renal cystic neoplasms and renal neoplasms associated with cystic renal diseases: pathogenetic and molecular links

Cystic renal neoplasms represent an isolated cystic mass not accompanied by cystic change of the renal parenchyma. Although cystic change may be seen in any type of renal neoplasm, a few (i.e., cystic renal cell carcinoma, cystic nephroma, cystic partially differentiated nephroblastoma, mixed epithelial and stromal tumor) are characterized by constant cystic change that may involve the entire tumor. Cystic kidney disease is characterized by cystic change, which usually involves the kidneys in a bilateral and diffuse pattern, does not create a discreet mass, and is due to hereditary or developmental conditions. Some of the cystic kidney diseases are not known to give rise to renal neoplasm; others such as autosomal polycystic kidney disease or multicystic dysplastic kidney may fortuitously coexist with renal neoplasms. Three conditions (acquired cystic kidney disease, tuberous sclerosis, and von Hippel-Lindau disease) are associated with renal neoplasms with such a high frequency that they are considered preneoplastic. This article reviews the differential diagnoses among cystic neoplasms. It also focuses on the underlying genetic and molecular mechanisms for the relationship between cystic renal diseases and renal neoplasms.

[Nephroblastoma in adults: apropos of 2 cases]

Adult nephroblastoma is a rare tumor. The authors report two new cases observed in a 30 and 34 years old men in whom the diagnosis was made by histo-pathology. They were admitted for enormous kidney mass. We performed nephrectomy in one case, and surgical biopsy in the other. No adjuvant treatment was given. The prognosis was fatal. They study the particular features of this tumour. Its prognosis appeared to be poorer than that of renal adenocarcinoma.

Mixed epithelial and stromal tumor of the kidney

We describe the clinicopathologic features of 12 patients with a distinctive tumor of the kidney characterized by a mixture of epithelial and stromal elements that form solid and cystic growth patterns. Similar tumors were reported previously in the literature under various names, including adult mesoblastic nephroma. All but one of the patients were women. The only man had a long history of treatment with lupron and diethylstilbesterol. Seven of the women had histories of long-term oral estrogen use of whom six had undergone total abdominal hysterectomy and bilateral salpingo-oophorectomy several years prior, and the seventh patient had been using oral contraceptives for many years. Another woman had this operation but did not receive any hormone therapy. Ages ranged from 31 to 71 years (mean, 56 yrs). Six patients presented with symptoms, including pain and infections attributable to mass effect, and in six the tumor was detected incidentally. Grossly, the tumors were well-circumscribed (mean size, 6 cm; range, 3-12 cm) and consisted of solid and cystic components, most often in equal proportions but in variable distribution. Microscopically, the spindle cell component ranged in appearance from scar-like fibrous tissue to leiomyoma-like interlacing fascicles; usually there was a mixture of both. More cellular foci reminiscent of ovarian stroma or solitary fibrous tumor were also present. No blastema was present. Epithelial elements (composed of clusters of tubules with variable lining) were scattered amidst the spindle cells, and focally transformed into large cysts lined by cells with abundant pink cytoplasm and a hobnail appearance. Immature epithelial elements typical of Wilms' tumor were not present. Muscle markers (desmin and smooth muscle actin) were positive diffusely and strongly in the spindle cells of all tumors, whereas HMB-45 and CD34 were absent. Estrogen receptors were detected in the nuclei of spindle cells in seven tumors and progesterone receptors in three. The distinctive clinicopathologic characteristics of these lesions warrant their classification as a separate category of kidney tumor. We suggest the descriptive term "mixed epithelial and stromal tumor" for this group until its nature and relationship to other kidney lesions are further clarified. Its preponderance in females with a history of long-term estrogen replacement and the history of long-term sex-steroid use in the only male patient, combined with the frequent content of estrogen and progesterone receptors in the spindle cells, suggest that the hormonal milieu plays a role in the evolution of these tumors. The clinical and pathologic parallels with mucinous cystic tumors of pancreas and liver raise the possibility of a common pathogenetic mechanism that may be linked to the periductal fetal mesenchyme. We think this entity is a benign composite neoplasm in which stroma and epithelium are both integral neoplastic components.