Tumor fibroso solitario de próstata: informe de caso y revisión de la literatura / Solitary fibrous tumor of the prostate: case report and literature review

El tumor fibroso solitario (TFS) es una neoplasia mesenquimatosa de tipo fibroblástico que, a pesar de ser localizado principalmente en pleura, se ha observado en otros órganos como la próstata. Por su parte, el tumor fibroso solitario de la próstata es una neoplasia de baja incidencia, crecimiento lento y potencial maligno incierto, que generalmente se compone de células fusiformes de apariencia citológicamente benignas, dispuestas en una arquitectura desorganizada, mezcladas con colágeno y pequeños vasos sanguíneos. Establecer su diagnóstico se ha vuelto más reproducible desde la identificación de la fusión de los genes NAB2-STAT6 por biología molecular, que lleva a la sobreexpresión de STAT6 por inmunohistoquímica, el cual es un marcador muy sensible y específico para TFS. Presentamos el caso clínico de un paciente que debutó con síntomas de compresión vesical, en quien se identificó una masa con epicentro en la próstata que infiltraba la vejiga y llegaba a la pared rectal, y que luego de estudios de patología, inmunohistoquímica y pruebas moleculares se clasificó como un TFS de la próstata, finalmente tratado con cistoprostatectomía radical más derivación urinaria

Solitary fibrous tumor (SFT) is a mesenchymal neoplasm of fibroblastic type, which despite being located mainly in the pleura, has been observed in other organs such as the prostate. On the other hand, solitary fibrous tumor of the prostate is a rare neoplasm, slow growing, and of uncertain malignant potential, which is generally composed of spindle cells of cytologically benign appearance, arranged in a disorganized architecture, mixed with collagen and small blood vessels. Establishing its diagnosis has become more reproducible since the identification of the NAB2-STAT6 gene fusion by molecular biology, leading to the overexpression of STAT6 by immunohistochemistry, a very sensitive and specific marker for SFT. We present a clinical report of a patient who consulted with symptoms of bladder compression, in whom a mass was identified with the epicenter in the prostate infiltrating into the bladder and reaching the rectal wall. Following histopathology study, immunohistochemistry and molecular tests it was classified as a SFT of the prostate, finally treated with radical cystoprostatectomy plus urinary shunt

Tumour immune microenvironment in primary and metastatic papillary renal cell carcinoma.

AIMS: Among renal cell carcinoma (RCC) the tumour immune microenvironment has been best characterised in clear cell RCC. In this study we investigated the expression of several immune markers, including PD-L1, FoxP3 and CD8 in primary and metastatic papillary RCC. METHODS AND RESULTS: Three tissue microarrays were constructed from 78 cases with primary papillary RCC and paired metastatic tumour (24 cases) from 78 patients treated between 1982 and 2014. Immunohistochemistry analysis was performed using commercially available antibodies for PD-L1 (clone E1L3N), FoxP3, CD8 and Ki-67. Markers expression level in tumour and/or associated immune cells was analysed by tissue type (non-tumour versus primary tumour versus metastatic tumour) and correlated to clinicopathological features and outcome. CONCLUSION: We found PD-L1 expression in up to one-quarter of primary and metastatic papillary RCC. On univariate analysis, CD8/FoxP3 ratio >1 was associated with favourable outcome, whereas papillary RCCs with high numbers of dual CD8/Ki-67-positive lymphocytes showed an increased likelihood for tumour progression and overall and cancer-related mortality. The association of CD8/FoxP3 ratio >1 and high count of CD8/Ki-67 with outcome remained significant on multivariate analysis when adjusting for stage, grade and patient's age.

Tumor immune microenvironment in non-muscle-invasive urothelial carcinoma of the bladder.

Immunotherapy has gained significance in a variety of tumor types including advanced urothelial carcinoma. Noninvasive urothelial lesions have been treated with intravesical Bacillus-Calmette-Guerin (BCG) for decades. Given treatment failure in a subset of these tumors, ongoing clinical trials investigating the role of checkpoint inhibitors are actively pursued in this group of patients. The present study aims to delineate PD-L1, CD8, and FOXP3 expression in tumor microenvironment in non-muscle-invasive urothelial carcinoma samples obtained via sequential biopsies and to assess its potential role in predicting disease outcome. Cases with >1% and> 5% PD-L1 expression in tumor cells showed lower relative risk (RR) to recur at any subsequent biopsy compared with those with lower PD-L1 expression (RRs, 0.83 [P = .009] and 0.81 [P = .03], respectively). Cases with higher expression of FOXP3 in peritumoral lymphocytes were at lower risk for tumor grade progression at any biopsy (RR, 0.2; P = .02). Tumors with FOXP3/CD8 expression ratio of >1 in intratumoral lymphocytes had lower risk of grade progression (RR, 0.28; P = .04). Although higher number of FOXP3-, CD8-, and PD-L1-positive lymphocytes were encountered after BCG treatment, the findings did not reach statistical significance. In patients without BCG treatment, PD-L1 expression in tumor cells and peritumoral lymphocytes varied across serial biopsies, suggesting the need for additional approaches to assess eligibility for immunotherapy in non-muscle-invasive urothelial carcinoma patients.

High prevalence of TERT promoter mutations in micropapillary urothelial carcinoma.

Somatic activating mutations in the promoter of the telomerase reverse transcriptase (TERT) gene are the most common genetic alterations in urothelial carcinoma (UC) of the bladder and upper urinary tract. Little is known, however, about TERT-mutation status in the relatively uncommon but clinically aggressive micropapillary (MPC) variant. We evaluated the presence of TERT promoter mutations in MPC of the bladder and upper urinary tract. A retrospective search of our archives for MPC and UC with micropapillary features (2005-2014) was performed. All slides were reviewed to confirm the histologic diagnosis. Thirty-three specimens from 31 patients had FFPE blocks available for DNA analysis and were included in the study. Intratumoral areas of non-micropapillary histology were also evaluated when present. Samples were analyzed with Safe-SeqS, a sequencing error reduction technology, and sequenced using the Illumina MiSeq platform. TERT promoter mutations were detected in all specimens with pure MPC (18 of 18) and UC with focal micropapillary features (15 of 15). Similar to conventional UC, the predominant mutations identified occurred at positions -124 (C228T) (85 %) and -146 (C250T) (12 %) bp upstream of the TERT ATG start site. In heterogeneous tumors with focal variant histology, intratumoral concordant mutations were found in variant (MPC and non-MPC) and corresponding conventional UC. We found TERT promoter mutations, commonly found in conventional UC, to be frequently present in MPC. Our finding of concordant intratumoral mutational alterations in cases with focal variant histology lends support to the common oncogenesis origin of UC and its variant histology.

The utility of STAT6 and ALDH1 expression in the differential diagnosis of solitary fibrous tumor versus prostate-specific stromal neoplasms.

Solitary fibrous tumor (SFT) diagnosis in prostate can be challenging on small biopsies. Prostatic stromal tumors of unknown malignant potential (STUMP) and SFT have overlapping features. NAB2-STAT6 gene fusions that were recently identified in various SFTs lead to nuclear translocalization of STAT6. Nuclear STAT6 immunostaining is now considered an adjunct for SFT diagnosis. We evaluated STAT6 and an emerging stemness marker, ALDH1, in the differential diagnosis of SFT versus prostatic stromal lesions. Sixteen STUMPs, 12 SFTs, and 4 prostatic stromal sarcomas (12 needle biopsies, 13 radical prostatectomies, 7 transurethral resections) were retrieved (1995-2015). Sections were stained with polyclonal STAT6 antibody (Santa Cruz Biotechnology, Santa Cruz, CA; S20, 1:100) and monoclonal ALDH1 antibody (BD Biosciences, San Jose, CA; clone 44, 1:250). In STAT6 cases, only unequivocal nuclear staining (with/without cytoplasmic staining) was considered positive. Cytoplasmic ALDH1 staining was counted positive. Ten of 11 evaluable SFTs demonstrated strong and diffuse nuclear STAT6 positivity; 4 of 16 STUMPs had nuclear staining that was weak (1/4) or focal (1/4). ALDH1 positivity was seen in 10 of 12 evaluable SFTs and 3 of 15 STUMPs. Prostatic stromal sarcomas were STAT6 negative (4/4); 2 of 4 were ALDH1 positive. The sensitivity and specificity for STAT6 for the diagnosis of SFT were 91% and 75%, respectively. Coexpression of STAT6 and ALDH1 yielded the same sensitivity but improved the specificity (100%) for the diagnosis of SFT. STAT6 is a useful marker in the differential diagnosis of SFT versus STUMP. Using STAT6 and ALDH1 together increases specificity. STUMPs can show STAT6 positivity, and when they do, it is likely to be weak or focal.

Detection of TERT promoter mutations in primary adenocarcinoma of the urinary bladder.

TERT promoter mutations (TERT-mut) have been detected in 60% to 80% of urothelial carcinomas. A molecular urine-based screening assay for the detection of TERT-mut is currently being pursued by our group and others. A small but significant number of bladder carcinomas are adenocarcinoma. The current study assesses the incidence of TERT-mut in primary adenocarcinomas of urinary bladder. A retrospective search of our institutional pathology records identified 23 cystectomy specimens with a diagnosis of adenocarcinoma (2000-2014). All slides were reviewed by a senior urologic pathologist to confirm tumor type and select a representative formalin-fixed, paraffin-embedded block for mutational analysis. Adequate material for DNA testing was available in 14 cases (7 enteric type and 7 not otherwise specified). TERT-mut sequencing analysis was performed using previously described SafeSeq technique. Overall, 28.5% of primary adenocarcinoma harbored TERT-mut. Interestingly, 57% of nonenteric adenocarcinomas were mutation positive, whereas none of the enteric-type tumors harbored mutations. Similar to urothelial carcinoma, we found a relatively higher rate of TERT-mut among nonenteric-type adenocarcinomas further supporting the potential utility of TERT-mut urine-based screening assay for bladder cancer.