Melanotic Xp11 translocation renal cancers: a distinctive neoplasm with overlapping features of PEComa, carcinoma, and melanoma. Am J Surg Pathol. 2009;33:609-619. [PMID: 19065101 DOI: 10.1097/pas.0b013e31818fbdff]

Dual-color, break-apart FISH assay on paraffin-embedded tissues as an adjunct to diagnosis of Xp11 translocation renal cell carcinoma and alveolar soft part sarcoma

Both Xp11.2 translocation renal cell carcinoma (RCC) and alveolar soft part sarcoma (ASPS) are characterized by various translocations disrupting chromosome Xp11.2, which result in gene fusions involving the TFE3 transcription factor gene. Diagnostic tools to detect translocations involving the TFE3 gene on chromosome X would be valuable in the evaluation of these tumors. We developed a dual-color, break-apart fluorescence in situ hybridization (FISH) assay to identify the chromosomal break point in paraffin-embedded tissue. This assay was validated using 4 cases of Xp11.2 RCC [proven by karyotype and/or reverse-transcriptase polymerase chain reaction (RT-PCR)], 2 cases of ASPS (proven by karyotype or RT-PCR), the UOK109 cell line carrying the inv(X) (p11;q12), and several negative controls (both neoplastic and non-neoplastic). This break-apart FISH assay is a relatively quick procedure for detecting Xp11.2 RCC and ASPS translocations and can be applied to archival paraffin-embedded tissue.

TFE3 expression in tumors of the microphthalmia-associated transcription factor (MiTF) family

The DNA-binding factor TFE3 is closely related to microphthalmia-associated transcription factor (MiTF) and is over-expressed in alveolar soft part sarcoma (ASPS) and select renal cell carcinomas. Reports of TFE3 expression in PEComa prompted investigation into TFE3 expression among other members of the putative MiTF group of neoplasms. The authors examined cases of PEComa (n = 6), conventional angiomyolipoma (AML; n = 22), metastatic melanoma (n = 16), and clear cell sarcoma (CCS; n = 9) for TFE3 expression. Nuclear immunostaining was observed in 74% (39/53) of cases, as follows: 5/6 PEComas, 18/22 AMLs, 10/16 metastatic melanomas, and 6/9 CCSs. However, with the exception of PEComas, compared with ASPS controls, TFE3 staining was significantly less intense in the tumors examined. These results illustrate that TFE3 immunoreactivity is detectable in other members of the MiTF family of neoplasms. For this reason, such neoplasms warrant consideration in the differential diagnosis with nuclear TFE3 immunoreactivity, particularly when staining is focal and less intense.

Renal epithelioid angiomyolipoma: a study of six cases and a meta-analytic study. Development of criteria for screening the entity with prognostic significance

AIMS

Renal epithelioid angiomyolipoma (EAML) is only described in case reports or in multi-institutional small series. The aim was to report cases seen at our institution and to perform a meta-analysis based on a literature review.

METHODS AND RESULTS

Six EAML cases seen at our institution were reviewed and a meta-analysis performed using cases retrieved from a literature review. There were a total of 69 cases for review. The male:female ratio was 1:3. In the absence of areas of typical AML, useful features in distinguishing EAML from epithelial renal neoplasms include: extreme degree of cytological atypia, histiocytoid appearance, presence of melanocytic pigments, solid architecture with the absence of frequent areas of alveolar pattern, tubulo-papillary formation and scarring. A fatal outcome, distant or lymph node metastasis, venous invasion and local recurrence were considered as adverse events and occurred in 40% of cases over a period of follow-up of 3-60 months (mean 22.5 +/- 18 months). Tumours with an unfavourable outcome showing marked cytological atypia and extensive tumour necrosis were larger (135 +/- 43 mm) than those with a favourable outcome (79 +/- 50 mm) (P < 0.002), and predominantly occurred in men.

CONCLUSIONS

Renal neoplasms with certain unusual features should be investigated immunohistochemically to rule out the possibility of EAML. The frequency of adverse outcome is lower in EAML than in renal cell carcinoma.

Genetic profiles in renal tumors

Renal cell carcinoma in adult comprises a heterogeneous group of tumors with variable clinical outcomes, which ranges from indolent to aggressively malignant. The application of molecular genetics techniques to the study of renal neoplasms has resulted in improved classification of these entities and better understanding of biological mechanisms responsible for tumor development and progression. In the present article we review the molecular genetic profiles of different renal cell tumors and discuss their relevance to the carcinogenesis mechanisms and to the clinical diagnosis of renal cell carcinoma. Understanding of the molecular genetics of renal tumors is beneficial in making accurate diagnoses, assessing prognoses, and selecting appropriate and targeted therapeutic options.

Xp11.2 translocation renal cell carcinoma occurring during pregnancy with a novel translocation involving chromosome 19: a case report with review of the literature

The recently recognized renal cell carcinomas (RCCs) associated with Xp11.2 translocations (TFE3 transcription factor gene fusions) are rare tumors predominantly reported in children. They comprise at least one-third of pediatric RCCs and only few adult cases have been reported. Here, we present a case of Xp11.2 translocation RCC in 26-year-old pregnant female. Her routine antenatal ultrasonography accidentally found a complex cystic right renal mass. Further radiologic studies revealed unilocular cyst with multiple mural nodules at inferior pole of right kidney, which was suspicious for RCC. She underwent right radical nephrectomy at 15 weeks gestation. Macroscopically, the cystic tumor was well encapsulated with multiple friable mural nodules on its inner surface. Microscopically, the tumor consisted of clear and eosinophilic/oncocytic voluminous cells arranged in papillary, trabecular, and nested/alveolar patterns. Occasional hyaline nodules and numerous psammoma bodies were present.

Immunohistochemically, the tumor showed strong nuclear positivity for TFE3. Epithelial membrane antigen, CD10, and E-cadherin were strongly positive. Cytokeratin AE1/AE3, cytokeratin CAM-5.2, calveolin, and parvalbumin were moderately positive. Cytokeratin 7, renal cell carcinoma antigen, and colloidal iron were focally weakly positive. BerEP4 and carbonic anhydrase IX were negative. Cytogenetically, the tumor harbored a novel variant translocation involving chromosomes X and 19, t(X;19)(p11.2;q13.1). Interphase FISH analysis performed on cultured and uncultured tumor cells using a dual-color break-apart DNA probe within the BCL3 gene on 19q13.3 was negative for the BCL3 gene rearrangement. She received no adjuvant therapy, delivered a normal term baby five months later, and is alive without evidence of disease 27 months after diagnosis and surgery. Unlike most recently reported Xp11.2 translocation RCCs in adult patients with aggressive clinical course, this adult case occurring during pregnancy with a novel translocation involving chromosome 19 followed an indolent clinical course.