Common Diagnostic Challenges and Pitfalls in Genitourinary Organs, With Emphasis on Immunohistochemical and Molecular Updates.

CONTEXT.­: Lesions in the genitourinary (GU) organs, both benign and malignant, can demonstrate overlapping morphology, and practicing surgical pathologists should be aware of these potential pitfalls and consider a broad differential diagnosis for each specific type of lesion involving the GU organs. The following summary of the contents presented at the 6th Annual Chinese American Pathologists Association (CAPA) Diagnostic Course (October 10-11, 2020), supplemented with relevant literature review, exemplifies the common diagnostic challenges and pitfalls for mass lesions of the GU system of adults, including adrenal gland, with emphasis on immunohistochemical and molecular updates when relevant. OBJECTIVE.­: To describe the common mass lesions in the GU system of adults, including adrenal gland, with emphasis on the diagnostic challenges and pitfalls that may arise in the pathologic assessment, and to highlight immunohistochemical workups and emerging molecular findings when relevant. DATA SOURCES.­: The contents presented at the course and literature search comprise our data sources. CONCLUSIONS.­: The diagnostic challenges and pitfalls that arise in the pathologic assessment of the mass lesions in the GU system of adults, including adrenal gland, are common. We summarize the contents presented at the course, supplemented with relevant literature review, and hope to provide a diagnostic framework to evaluate these lesions in routine clinical practice.

The Role of PD-L1 Testing in Advanced Genitourinary Malignancies.

In accordance with US Food and Drug Administration recommendations, tumor PD-L1 expression should be assessed in all patients with platinum-ineligible metastatic urothelial carcinoma (mUC), and patients with low PD-L1 expression should not receive single-agent immune checkpoint inhibition treatment. By contrast, PD-L1 should not be tested in metastatic renal cell carcinoma and platinum-refractory mUC.

Management of advanced genitourinary tumors.

The management of advanced genitourinary tumors is rapidly evolving thanks to the clinical availability of several targeted drugs with different mechanisms of action. Among clinicians, in-depth knowledge of all the aspects of the disease, together with the capacity to interpret and accurately correlate clinical data and imaging findings, are strongly needed. Moreover, the optimization of treatment sequences might lead to better disease control with respect to prognostic categories, radiological monitoring and newer biomarkers. Among the genitourinary tumors, only few data are available on bladder, testicular and penile cancers. Our report is supported by scientific and clinical experience in renal cell carcinoma and prostate cancer.

New perspectives in advanced genitourinary malignancies.

The management of advanced genitourinary malignancies has undergone a major transformation with the advent of novel drugs and targeted therapies in recent years. Assessment of the treatment risks and benefits is required for each patient and therefore better knowledge of the different clinical and molecular aspects of these diseases is warranted. The results of further studies and biomarker validations are expected to provide more treatment options and improve outcomes in the future management of genitourinary malignancies.

Anastomosing hemangioma of the genitourinary tract: a lesion mimicking angiosarcoma.

BACKGROUND: We describe 6 cases of a poorly recognized vascular neoplasm that can simulate angiosarcoma. DESIGN: Cases of a rare vascular tumor with a proclivity for the genitourinary tract encountered in our consultation material were prospectively collected between the year 1999 and 2008. Follow-up information was obtained when possible. RESULTS: There were 6 tumors from 4 men (66%) and 2 women, ranging in age from 49 to 75 years (median, 59.5) involving the kidney and renal hilum (4, 66%) and testis (2). Tumors ranged from 1.3 to 1.7 cm (median, 1.6 cm) and were grossly well-marginated with a hemorrhagic mahogany spongy appearance. Microscopically, at low power they had a loosely lobulated architecture and were associated with a medium-caliber vessel (5/6, 83%). Most kidney (3/4, 75%) tumors showed minor extensions into adjacent adipose tissue. At higher magnification, the tumors consisted of anastomosing sinusoidal capillary-sized vessels with scattered hobnail endothelial cells within a framework of nonendothelial supporting cells. There was a minimal inflammatory backdrop consisting of lymphocytes but not plasma cells or acute inflammation. Mitoses were absent (5/6, 83%) or rare (1 case; in supporting cells). There was mild cytologic atypia in one of the cases but no multilayering of endothelial cells in any case. Vascular thrombi were typical (5/6, 83%) and the lesions had zones of central sclerosis with focal necrosis (5/6, 83%). Two (33%) tumors featured prominent extra-medullary hematopoiesis and 2 tumors (33%) had striking hyaline globules reminiscent of those seen in Kaposi's sarcoma. Immunohistochemistry was available on some cases and the lesions stained with CD34, CD31, and FVIII but not human herpes virus type 8, keratin AE1/3, epithelial membrane antigen, HMB45, placental alkaline phosphatase, or human chorionic gonadotropin. In all but one submitted consultation, the possibility of angiosarcoma had been raised based on the anastomosing vascular pattern. On follow-up, there were no recurrences or metastases in 5 cases (range: 8 to 36 mo; median 12 mo, mean 15 mo), and 1 patient was lost to follow-up. CONCLUSIONS: Anastomosing hemangioma of the genitourinary tract is a rare neoplasm displaying some overlapping features of both sinusoidal hemangioma and hobnail hemangioma of soft tissue and skin. However, in our opinion, it is a unique neoplasm with a proclivity for the kidney. Its anastomosing appearance can lead to concern for angiosarcoma but, despite small numbers and limited follow-up in our series, evidence to date supports that the lesion is benign.

Myogenin and desmin immunohistochemistry in the assessment of post-chemotherapy genitourinary embryonal rhabdomyosarcoma: prognostic and management implications.

PURPOSE: Posttreatment genitourinary embryonal rhabdomyosarcoma often shows well differentiated rhabdomyoblasts, which are detectable on routine histological staining. Definite areas of residual undifferentiated rhabdomyosarcoma indicate residual/recurrent disease. However, the recent use of immunohistochemical staining with desmin and myogenin in resected specimens and surveillance biopsies following adjuvant therapy may demonstrate scant positive staining cells that appear undifferentiated on light microscopy. To our knowledge the clinical significance of this finding is currently unknown. Therefore, we reviewed our retrospective experience with genitourinary embryonal rhabdomyosarcoma to examine the relationship between immunostain positive undifferentiated cells and subsequent clinical outcome. MATERIALS AND METHODS: A total of 14 children with a median age of 2.75 years (range 8 months to 7 years) with genitourinary embryonal rhabdomyosarcoma were identified in the histopathology database. All had biopsy confirmation of the diagnosis, followed by multi-agent chemotherapy. Two children in whom there was obvious residual active tumor at the resection margins were excluded from further analysis. Histopathological findings in all patients on the resection/posttreatment biopsy were reviewed. All specimens were immunostained with desmin and myogenin to detect residual undifferentiated rhabdomyoblasts. The relation between histopathological findings and outcome was determined. RESULTS: There were 14 cases of genitourinary embryonal rhabdomyosarcoma. In 2 cases (14%) residual embryonal tumor was pathologically confirmed following initial treatment. In 12 cases no obvious residual tumor was present following initial therapy. Rhabdomyosarcoma affected the bladder in 10 cases and the vagina in 2. There were no distant metastases in any child. Ten patients underwent local resection following chemotherapy and 2 underwent followup biopsies only without resection. A total of 11 cases showed well differentiated, posttreatment rhabdomyoblasts that was identifiable on routine hematoxylin and eosin staining with margins apparently free of tumor and 1 showed no morphological evidence of residual rhabdomyosarcoma. However, all cases demonstrated at least scant abnormal desmin and myogenin positive cells in the specimens. Four patients had no further treatment and none had clinical recurrence. All were well 10 years (range 8 to 13) after treatment. Eight patients received further treatment (chemotherapy and/or radiotherapy) based on clinical and pathological findings, followed by further resection in 3. One patient died of disease but 7 were well a median of 7.2 years (range 8 months to 13 years) after treatment. CONCLUSIONS: The significance of undifferentiated myogenin/desmin positive cells in genitourinary embryonal rhabdomyosarcoma in the absence of morphological residual/recurrent embryonal rhabdomyosarcoma remains unclear since such cells can be detected in all cases of posttreatment embryonal rhabdomyosarcoma. In some cases findings are associated with clinical disease recurrence, while others with identical histopathological findings following initial treatment have no clinical sequelae even in the absence of further treatment. In genitourinary embryonal rhabdomyosarcoma close and regular clinical surveillance is essential. Desmin/myogenin immunohistochemistry to detect scattered undifferentiated cells does not appear to provide useful prognostic information.

Tissue microarrays and their relevance to the urologist.

PURPOSE: We review important aspects of TMA methodology and discuss its wide range of clinical applications with particular emphasis on key clinical studies. We also provide an update on recent and projected uses of this technology to help the urologist improve care in oncology patients. MATERIALS AND METHODS: A directed MEDLINE literature review of TMAs was performed. Important publications that have shaped our understanding of TMAs were selected for review. They were augmented by manual searches and our personal bibliographic collections. RESULTS: The TMA is a high throughput molecular biology technique that can significantly accelerate the processing of a large number of tissue specimens with excellent quality, good reliability and the preservation of original tissue. TMA studies demonstrate their accuracy and reliability compared to those of standard histological techniques and correlate with clinicopathological information to determine disease progression and prediction of the clinical outcome. CONCLUSIONS: This review represents an overview and update for the urologist on TMAs and their clinical applications in urological oncology. In the future it is anticipated that the outcomes of this method will be used to assist in the diagnosis, prognosis and development of novel therapies in individual patients.

Role of the nuclear matrix proteins in malignant transformation and cancer diagnosis.

The nuclear matrix (NM) is the structural framework of the nucleus that consists of the peripheral lamins and pore complexes, an internal ribonucleic protein network, and residual nucleoli. Differences between the nuclear matrix protein (NMP) composition of transformed cells and their normal homologues were detected in numerous cases. Actually several tumor-specific nuclear matrix proteins (NMPs) are proposed for diagnostic of bladder, breast, colon and some other cancers. According to the role of NMPs in development and phenotype of a given neoplasms the tumors can be classified as follows: I. Tumors bearing mutations in the genes encoding NMPs. The group consists of following subgroups: 1) hereditary cancer syndromes with mutations in the NM-attached oncoproteins or tumor suppressor genes; 2) sporadic tumors with somatic mutations in the NM-attached oncoproteins, tumor suppressor genes or replication enzymes; 3) leukemias with fused NMPs. II. Tumors with phenotypic quantitative or qualitative changes of the NMP spectrum.

Localization of S100C immunoreactivity in various human tissues.

Using 2-dimensional gel electrophoresis, we previously demonstrated that the S100C protein remarkably decreased after immortalization of normal human fibroblasts, and that this protein caused growth inhibition of human tumor cells when forcibly expressed in these cells, suggesting that S100C plays a significant role in tumor suppression. The present study was carried out to determine what type of human tissues express S100C protein, and, subsequently, whether the S100C content in these tissues changes after normal cells have been transformed into cancer cells. We found that ductal cells in various tissues were positively stained with the S100C protein. In comparison, epithelial cells in digestive organs such as the stomach, small intestine, and colon were not stained as strongly. When 14 pairs of human normal and cancerous tissues were stained with the antibody, decreases in the staining levels of S100C were observed in 6 kinds of cancerous tissues--from the bronchus, mammary duct, renal tubule, prostate, uterus, and testis--in comparison with staining in their normal counterparts. These results suggest that S100C is a new tumor marker protein, the expression of which significantly decreases after malignant transformation of human tissues.

Pseudosarcomatous myofibroblastic tumor and myosarcoma of the urogenital tract.

OBJECTIVE: Pseudosarcomatous myofibroblastic tumors (PMTs) of the urogenital tract are rare but distinctive lesions. Despite their benign behavior, they are frequently misinterpreted as leiomyosarcomas and rhabdomyosarcomas in preoperative biopsies and even in resected specimens because of their atypical spindle-cell features. Precise diagnosis of PMTs is important to avoid unnecessary radical therapy. We analyzed urogenital myoid tumors to clarify which of their characteristics are useful for the differential diagnosis. METHODS: We evaluated 7 urogenital myoid tumors consisting of 3 PMTs, 2 leiomyosarcomas, and 2 rhabdomyosarcomas. We studied the expression of various immunohistochemical muscle-cell markers including desmin, muscle-specific actin, alpha-smooth muscle actin, high-molecular-weight caldesmon, and myogenin. RESULTS: Desmin, muscle-specific actin, and alpha-smooth muscle actin were noted variably in all tumor types, whereas high-molecular-weight caldesmon was expressed only in leiomyosarcomas, and myogenin was expressed only in rhabdomyosarcomas. CONCLUSION: High-molecular-weight caldesmon and myogenin are useful for differentiating urogenital PMTs from myosarcomas.

Local synthesis of amyloid fibril precursor in AL amyloidosis of the urinary tract.

An amyloid tumor localized to the urethra was resected and shown by immunohistochemistry to contain fibril deposits that stained with antisera specific for lambda VI immunoglobulin light chain. The amino acid sequence of the fibril protein was homologous to lambda VI Positive staining of subepithelial plasma cells with lambda VI specific monoclonal antibody was consistent with the hypothesis that the fibril precursor light chain protein is synthesized and processed locally to give this type of localized amyloidosis.

[A study on the relationship between sensitivity to CDDP and inducibility of metallothionein and glutathione of genitourinary tumors].

BACKGROUND: In this paper we demonstrate the relationship between the antitumor activity of cis-diamminedichloroplatinum (II) (CDDP) and inducibility of metallothionein (MT) and glutathione (GSH) of genitourinary tumors. METHODS: The chemosensitivity test was performed in athymic mice bearing tumors derived from the human tumor cell lines: ACHN (renal cell carcinoma), NMB-1 (urinary bladder transitional cell carcinoma), and NMT-1 (testicular embryonal cell carcinoma). A single dose of CDDP (25 mumol/kg body weight), was administered i.p. to athymic tumor bearing mice. Concentrations of platinum, MT, and GSH were measured in organ and tumor homogenates 24 h after CDDP administration. RESULTS: We observed that tumors derived from NMB-1 and NMT-1 were very sensitive to CDDP, but ACHN derived tumors were resistant to CDDP. Measurement of platinum concentrations in tumor tissues revealed no correlation to the observed chemosensitivities of the tumors. Furthermore, 24 h after CDDP administration, the levels of MT and GSH in NMB-1 and NMT-1 derived tumors were lower them or equal to those of control mice. In contrast, mice bearing tumors derived from ACHN exhibited a 1.7-fold and a 2.1-fold increase in MT and GSH, respectively, as compared to control mice. CONCLUSION: These findings suggest that the inducibility of MT and GSH in tumor tissues following CDDP administration may be a contributing factor in the development of CDDP resistance in renal cell carcinoma.

Keratin 20: immunohistochemical marker for gastrointestinal, urothelial, and Merkel cell carcinomas.

Keratin 20 is a recently identified keratin protein distributed particularly in the epithelial cells of the gastrointestinal tract. In this study, keratin 20 was immunohistochemically evaluated in 788 epithelial tumors of different organs. Keratin 20 was consistently present in colonic adenocarcinomas and their metastases in lymph nodes, liver, lung, and ovaries; most primary and metastatic colon carcinomas showed high numbers of positive cells independent of their level of differentiation. Adenocarcinomas of the upper gastrointestinal tract, pancreas, and cholangiocarcinomas showed variable reactivity. Hepatocellular carcinomas and carcinoid tumors often showed focal reactivity limited to scattered tumor cells. In contrast, keratin 20 was virtually absent in primary adenocarcinomas of lung, ovaries, and endometrium. Notable exceptions among ovarian tumors were the mucinous neoplasms that showed variable, sometimes significant keratin 20 reactivity. Transitional cell carcinomas irrespective of grade were usually positive, whereas most prostatic and renal adenocarcinomas were negative or showed only single positive cells. Typically negative were squamous cell carcinomas of all organs and carcinomas of the breast. Merkel cell carcinomas of the skin showed consistent reactivity, whereas small cell carcinomas of the lung were negative. On the basis of these observations, keratin 20 seems to be a suitable adjunct marker to evaluate the primary origin of carcinomas in specific contexts, especially to separate adenocarcinomas of gastrointestinal versus nongastrointestinal origin.

The expression pattern of contractile and intermediate filament proteins in developing skeletal muscle and rhabdomyosarcoma of childhood: diagnostic and prognostic utility.

In order to investigate whether rhabdomyosarcoma (RMS) can be related to equivalent stages of skeletal muscle development, muscle tissue of 21 human foetuses and 112 primary RMSs were characterized immunohistochemically using antibodies directed against vimentin, desmin, muscle-specific actin (HHF35), sarcomeric actin (sr-actin), smooth muscle actin (sm-actin), and troponin-T. During fetal skeletal muscle development, all myotubes/fibres of the first and second generations expressed desmin, HHF35, and sr-actin. Vimentin was almost exclusively present in immature primary and secondary myotubes/fibres. Troponin-T was expressed in immature myotubes/fibres of the first and second generations as well as mature fibres of the second generation. Sm-actin was never expressed. Vimentin was expressed in 96 per cent of primary and 98 per cent of relapsed RMS; HHF35 in 96 and 98 per cent, respectively; desmin in 95 and 100 per cent; troponin-T in 82 and 75 per cent; sr-actin in 71 and 86 per cent; and sm-actin in 13 and 17 per cent. The proportion of RMS cells reacting with vimentin, HHF35, and desmin was consistently higher than those expressing sr-actin and troponin-T. Neither the shape nor size of neoplastic RMS cells nor the histopathological types were related to the expression pattern of the investigated markers. RMS with aberrant expression of two or more markers predicted a worse prognosis than RMS in which at most one marker was aberrantly expressed (25 per cent and 54 per cent 10-year survival, P = 0.01). These results demonstrate that HHF35, desmin, sr-actin, and troponin-T have the potential to confirm the commitment of the tumours to the myogenic pathway which supports the diagnosis of RMS. However, it was impossible to relate RMS to equivalent stages of skeletal muscle development. Aberrant marker expression by RMS cells correlated significantly with patients' survival.

[Expression of integrin molecule in urological tumor cell lines by using RT-PCR method].

Integrins are heterodimer molecule that are composed of one alpha subunit and one beta subunit. Integrins appear to be the major receptors by which cells attach to extracellular matrices, and some integrins also mediate important cell-cell adhesion event. In recent years signaling pathway via beta subunit of integrin molecule has been clarified, and 8 kinds of integrin beta subunit are known to exist. And so we investigated the expression of integrin beta subunit in various urological tumor cell lines by using RT-PCR method. Materials are composed of 8 renal cell carcinoma cell lines, 2 urinary bladder carcinoma cell lines, a testicular tumor cell line and a prostate tumor cell line. All 12 cell lines express integrin beta 1 subunit. The expression rate of beta 4 subunit in renal cell carcinoma lines are lower than that in other urological tumor cell lines. The expression of beta 6 subunit was observed in renal cell carcinoma cell lines and testicular tumor line. In testicular tumor cell line we also found the expression of beta 2 subunit which expression had been believed to be specific in leukocyte.

Sarcomatoid lesions of the urogenital tract.

Spindle-cell lesions other than sarcomas are relatively rare occurrences along the urogenital tract but include both benign and malignant processes. Inflammatory pseudotumors may occur anywhere along the urothelial tract; they may follow a surgical procedure or appear de novo. Malignant tumors may be classified as sarcomatoid carcinomas or carcinosarcomas according to their degree of differentiation, the latter containing obvious mesenchymal components. Generally both arise in a background of high-grade carcinoma and are of a high pathological stage at the time of initial presentation. For this reason they have a poor prognosis. Because the deferential diagnosis of spindle-cell neoplasms include both benign and malignant lesions, great care must be taken in making the correct diagnosis.

Detection of P-glycoprotein in human urogenital carcinomas and its relationship to epidermal growth factor receptor expression.

P-glycoprotein and epidermal growth factor (EGF) receptor expression were surveyed immunohistochemically in the tissue of urogenital carcinomas including 12 renal cell carcinomas, 9 bladder transitional cell carcinomas, 2 prostate adenocarcinomas and 1 penile squamous cell carcinoma. Three bladder carcinomas and the penile carcinoma were following initial chemotherapy at the time of relapse. P-glycoprotein expression was detected in 3 of 12 renal cell carcinomas and in all recurrent carcinomas. EGF receptor was not detected in any of the specimens.