Expression analysis of kidney-specific cadherin in a wide spectrum of traditional and newly recognized renal epithelial neoplasms: diagnostic and histogenetic implications

Kidney-specific cadherin (Ksp-cad) is a membrane-associated cell adhesion glycoprotein expressed by the distal nephron tubular cells in its later developmental stages. Chromophobe renal cell carcinoma and renal oncocytoma are reported to be variably positive for Ksp-cad with some studies suggesting a discriminatory role for Ksp-cad. Immunoreactivity in other tumors with granular eosinophilic cytoplasm including clear cell and papillary renal cell carcinomas needs to be clearly elucidated and its expression in emerging novel and other unusual renal epithelial neoplasm subtypes including tumors with uncertain histogenesis is not yet known. In this study, we performed a detailed immunohistochemical analysis for Ksp-cad in a broad range of 136 renal epithelial neoplasms. Reactivity with Ksp-cad was observed in the following tumors: chromophobe renal cell carcinoma [23/25 (92%), diffuse (>50% of tumor cells)] positivity and membranous characteristically accentuating the "plant cell-like" histomorphology of the typical (clear) type, renal oncocytoma [15/20 (75%), usually diffuse staining with predominantly membranous accentuation], papillary renal cell carcinoma [5/17 (29%) all focal to moderate, eosinophilic type or type 2-3/7 (43%), basophilic type or type 1-2/10 (20%)], Xp11 translocation carcinoma [1/4 (25%), diffuse positivity] and clear cell renal cell carcinoma [6/36 (17%) all focal, clear cell renal cell carcinoma with prominent eosinophilic cells 1/7 (14%)]. Immunoreactivity was higher when evaluating whole histologic sections than with tissue microarrays for both chromophobe renal cell carcinoma (100% vs. 60%) and renal oncocytoma (100% vs. 55%). No immunoreactivity was observed in mucinous tubular and spindle cell carcinomas (0/23), high-grade collecting duct carcinomas (of Bellini) (0/3), renal medullary carcinomas (0/2), and urothelial carcinomas (0/6). Our study documents the immunoreactivity of Ksp-cad in the range of contemporarily classified renal epithelial neoplasms. The findings argue against the use of Ksp-cad in differentiating chromophobe renal cell carcinoma and renal oncocytomas and further support their relationship to the distal nephron. Ksp-cad may be helpful in distinguishing these two tumor types from clear cell renal cell carcinoma with prominent eosinophilic cells particularly in cases with limited tissue samples (ie, needle core biopsy). In the similar diagnostic setting, caution must be exercised, however, in differentiating chromophobe renal cell carcinoma and renal oncocytoma from the eosinophilic variant of papillary renal cell carcinoma as moderate expression of Ksp-cad may be observed in papillary renal cell carcinoma. The histogenesis of mucinous tubular and spindle cell carcinoma remains debatable as this tumor does not express Ksp-cad, which is highly expressed normally in the thick ascending loop of Henle and the distal convoluted tubules. In conclusion, Ksp-cad is a useful tumor type associated marker for distinguishing chromophobe renal cell carcinoma and renal oncocytoma from the wide range of nonintercalated cell-related adult renal epithelial neoplasms; addition of this marker to a panel comprised of other histologic subtype-associated markers may greatly facilitate histologic subclassification of adult renal epithelial neoplasms.

Cystic nephroma and mixed epithelial and stromal tumor of kidney: a detailed clinicopathologic analysis of 34 cases and proposal for renal epithelial and stromal tumor (REST) as a unifying term

Cystic nephroma (CN) and mixed epithelial and stromal tumor (MEST) are rare benign renal neoplasms that have overlapping clinical and morphologic features, including predominance in middle-aged women, variably cystic architecture, eosinophilic cells, and hobnail cells lining the cysts and ovarian-type stroma. The aim of this study was to analyze and compare the histologic features and immunohistochemical profile of these tumors. We studied 34 cases from 5 large academic institutions. Twenty tumors were diagnosed as CNs, 18 in women and 2 in men, their age ranged from 24 to 63 (mean 48; median 50) years. Fourteen tumors were diagnosed as MESTs, all in women, their age ranged from 26 to 84 (mean 52; median 51) years. Histologically, all tumors were well-circumscribed except for one MEST. The stromal/epithelial ratio was approximately 2.3 in MESTs versus 0.3 in CNs; cellular ovarian-type stroma composed 45% of the stroma in MESTs and 12% of the stroma of CNs. Stromal hyalinization was prominent in both. Five MESTs showed stromal luteinization. In the epithelial component, the relative amount of large cysts, medium to small cysts, and phyllodes-type glands was: 65%/25%/10% in CNs versus 25%/40%/35% in MESTs. The epithelial component ranged from flat to cuboidal to hobnail cells in both types of tumors. No significant atypia of either component was seen, although the epithelial cells showed reactive changes. Immunohistochemical stains for estrogen receptors and progesterone receptors showed 62% and 85% positivity in the stromal component of MESTs versus 19% and 40% in CNs. CD10 positivity was seen in 77% of MESTs versus 50% of CNs, calretinin was seen in 69% of MESTs versus 41% of CNs, and inhibin in 42% of MESTs versus 36% of CNs, although the staining was focal. Follow-up in both categories of tumors (mean 3.2 y, median 3 y for CNs and mean 2.5 y, median of 2 y for MESTs) showed no evidence of recurrence or metastases in keeping with their benign nature. This study highlights the remarkable similarity between CN and MEST in sex predilection, age distribution, and morphologic attributes of both the epithelial and stromal components and immunohistochemical profile albeit with variation in individual categories with higher prevalence of stromal to epithelial ratio, prominent ovarian stroma, smaller cysts with phyllodes glands pattern and stromal luteinization being more common in MEST; and large cysts, thin septae and low stromal to epithelial ratio in CN. The presence of ovarian-type stroma and müllerian related immunohistochemical markers raises the possibility that these tumors may originate from müllerian remnants misplaced during embryogenesis. On the basis of detailed morphologic analysis of this series of CN and MEST, we propose a unifying term of "renal epithelial and stromal tumor" (REST) to encompass the spectrum of findings observed in these tumors at least until new molecular studies can prove or disprove this challenging hypothesis.

Common and uncommon histologic subtypes of renal cell carcinoma: imaging spectrum with pathologic correlation

Renal cell carcinoma (RCC) is a cause of significant morbidity and mortality, with an estimated 35,000 new cases and 12,480 deaths in the United States in 2003. Recent advances in imaging technology, pathology, urology, and oncology permit early diagnosis of RCC and facilitate optimal management. The 2004 World Health Organization classification for renal neoplasms recognizes several distinct histologic subtypes of RCC. These subtypes include clear cell RCC, papillary RCC, chromophobe RCC, hereditary cancer syndromes, multilocular cystic RCC, collecting duct carcinoma, medullary carcinoma, mucinous tubular and spindle cell carcinoma, neuroblastoma-associated RCC, Xp11.2 translocation-TFE3 carcinoma, and unclassified lesions. Different histologic subtypes of RCC have characteristic histomorphologic and biologic profiles. Clear cell RCC is the most common subtype and has a less favorable prognosis (stage for stage) than do papillary RCC and chromophobe RCC. Collecting duct carcinoma and renal medullary carcinoma are associated with aggressive clinical behavior and a poor prognosis.

Large cell neuroendocrine carcinoma of prostate: a clinicopathologic summary of 7 cases of a rare manifestation of advanced prostate cancer

Neuroendocrine (NE) differentiation in prostate cancer is typically detected by immunohistochemistry as single cells in conventional adenocarcinoma. Prostatic NE tumors, such as carcinoid or small cell carcinoma, are rare and large cell NE carcinoma (LCNEC) is described only in case reports. We identified 7 cases of LCNEC and compiled their clinicopathologic characteristics. In 6 cases, there was a history of adenocarcinoma treated with hormone therapy for a mean of 2.4 years (range: 2 to 3 y). The remaining case was de novo LCNEC. LCNEC was incidentally diagnosed in palliative transurethral resection specimens in 5 cases. The mean patient age at diagnosis with LCNEC was 67 years (range: 43 to 81 y). LCNEC comprised solid sheets and ribbons of cells with abundant pale to amphophilic cytoplasm, large nuclei with coarse chromatin and prominent nucleoli along with brisk mitotic activity and foci of necrosis. In 6 cases, there were foci of admixed adenocarcinoma, 4 of which showed hormone therapy effects. LCNEC was strongly positive for CD56, CD57, chromogranin A, synaptophysin, and P504S/alpha methylacyl CoA racemase. There was strong bcl-2 overexpression, expression of MIB1, and p53 in >50% of nuclei, focally positive staining for prostate specific antigen and prostatic acid phosphatase and negative androgen receptor staining. Follow-up was available for 6 patients, all of who died with metastatic disease at mean of 7 months (range: 3 to 12 mo) after platinum-based chemotherapy. LCNEC of prostate is a distinct clinicopathologic entity that typically manifests after long-term hormonal therapy for prostatic adenocarcinoma and likely arises through clonal progression under the selection pressure of therapy.

Key issues in handling and reporting radical prostatectomy specimens

CONTEXT

Patients with prostatic adenocarcinoma commonly undergo radical prostatectomy, and it is often difficult and time consuming to handle the resulting specimens and to report the findings. Pathologic information derived from the radical prostatectomy specimen is used for selecting adjuvant therapy, such as radiotherapy and hormone therapy, and for determining a patient's prognosis. The prostate specimen must be handled in a systematic fashion to derive the appropriate prognostic parameters.

OBJECTIVE

To review the prognostic factors of relevance in classifying radical prostatectomy specimens, using the College of American Pathologists categorization system, including a detailed survey of the morphologic-based factors but excluding other factors such as DNA ploidy and novel phenotypic and genotypic markers.

CONCLUSIONS

Gleason score, pathologic stage, and margin status are considered category 1 prognostic factors, which are of proven prognostic significance and are useful in patient management. Factors such as tumor volume (intraglandular extent) and tumor subtype are considered category 2 prognostic factors, which show significant promise but require validation in multivariate analysis. Lymphovascular space invasion is a promising category 3 prognostic factor that needs additional study. Perineural invasion is an almost ubiquitous finding in radical prostatectomy specimens and is considered a category 3 prognostic factor. After prognostic factors have been analyzed at the histologic level, it is critical to report the findings in a clear and unambiguous fashion. The synoptic style of reporting is ideal for describing complex cancer resection specimens. A synoptic report based on an evidence-based checklist, such as the one developed by the College of American Pathologists, effectively communicates complex cancer-related data, such as radical prostatectomy specimen findings. This information is used not only for individual case management with respect to treatment and prognostication but also for purposes such as education, research, quality monitoring, and system planning.

Immunohistochemical Analysis of Mucinous Tubular and Spindle Cell Carcinoma and Papillary Renal Cell Carcinoma of the Kidney

Mucinous tubular and spindle cell carcinoma, a rare, recently described distinctive subtype of renal cell carcinoma, may have some morphologic similarities to the more common papillary renal cell carcinoma, particularly the basophilic (type 1) tumors with prominent solid growth pattern. Tumor circumscription, compact tubular architecture, focal papillations, mucin production and foam cells (features seen in both papillary renal cell carcinoma and mucinous tubular and spindle cell carcinoma), as well as spindle cell morphology, have resulted in some cases sent to us in consultation with a question of possible sarcomatoid papillary renal cell carcinoma. In this study, tissue microarrays with triplicate samples each from 27 mucinous tubular and spindle cell carcinomas and 20 papillary renal cell carcinomas were created to simulate experience in renal biopsy specimens. From immunohistochemistry (IHC) data, published in the contemporary literature, a panel consisting of alpha-methylacyl-CoA racemase (AMACR), cytokeratin 7 (CK7), epithelial membrane antigen (EMA), renal cell carcinoma marker (RCC Ma), CD10, high molecular weight cytokeratin (HMWK), and c-kit was designed to test its utility in differential diagnosis. The immunoreactivity in mucinous tubular and spindle cell carcinoma was AMACR 93%, CK7 81%, EMA 95%, RCC Ma 7%, CD10 15%, HMWK 15%, and c-kit 5% and in papillary renal cell carcinoma was AMACR 95%, CK7 65%, EMA 88%, RCC Ma 25%, CD10 80%, HWMK 15%, and c-kit 18%. This largest study to date on IHC of mucinous tubular and spindle cell carcinoma dispels the specificity of AMACR for papillary renal cell carcinoma among the RCC subtypes. The histogenesis of mucinous tubular and spindle cell carcinoma from the distal nephron continues to be debatable, as our study showed the expression of the proximal convoluted tubule-related marker AMACR among these tumors. Thus, in tumors with predominant compact tubular growth and focal papillary architectures, careful attention to the presence of a low-grade spindle cell population may be helpful in the distinction of mucinous tubular and spindle cell carcinoma, as the key immunohistochemical stains for papillary renal cell carcinoma are also expressed in this subtype of renal cell carcinoma.

Prognostic and predictive factors in prostate cancer: historical perspectives and recent international consensus initiatives

An understanding of prognosis in cancer medicine is important for patient care, research and cancer control programs. In prostate cancer, prognostic (predictive) factors are particularly important given the marked heterogeneity of this disease at clinical, morphologic and biomolecular levels. Clinical stage and histologic grade have historically played major roles in defining heterogeneity in prostate cancer. More recently, serum prostate-specific antigen measurement has assumed a significant prognostic role. Over the last two decades there has been an explosion of research into biomarkers, many of which have been purported to have prognostic significance. In this paper we present an overview of the various consensus initiatives that have transpired over the last dozen years. Criteria for evaluating prognostic factors and classifications of predictive factors have emerged that have proven useful and advanced our understanding of the biology of prostate cancer. The results of these consensus initiatives form a foundation on which the current international consultation on prognosis (prediction) in prostate cancer is built. Advances in our understanding of the new and promising prognostic factors will require a more rigorous evidence-based approach to the analysis of published studies. Furthermore, appropriate mathematical models for the analysis of the multiple factors that influence a prognostic system will have to be employed.

Prognostic and predictive factors and reporting of prostate carcinoma in prostate needle biopsy specimens

The information provided in the surgical pathology report of a prostate needle biopsy of carcinoma has become critical in the subsequent management and prognostication of the cancer. The surgical pathology report should thus be comprehensive and yet succinct in providing relevant information consistently to urologists, radiation oncologists and oncologists and, thereby, to the patient. This paper reflects the current recommendations of the 2004 World Health Organization-sponsored International Consultation, which was co-sponsored by the College of American Pathologists. It builds on the existing work of several organizations, including the College of American Pathologists, the Association of Directors of Anatomic and Surgical Pathologists, the Royal Society of Pathologists, the European Society of Urologic Pathology and the European Randomized Study of Screening for Prostate Cancer.

Prognostic factors and reporting of prostate carcinoma in radical prostatectomy and pelvic lymphadenectomy specimens

This paper, based on the activity of the Morphology-Based Prognostic Factors Committee of the 2004 World Health Organization-sponsored International Consultation, describes various methods of handling radical prostatectomy specimens for both routine clinical use and research purposes. The correlation between radical prostatectomy findings and postoperative failure is discussed in detail. This includes issues relating to pelvic lymph node involvement, detected both at the time of frozen section and in permanent sections. Issues of seminal vesicle invasion, including its definition, routes of invasion and relationship to prognosis, are covered in detail. The definition, terminology and incidence of extra-prostatic extension are elucidated, along with its prognostic significance relating to location and extent. Margins of resection are covered in terms of their definition, the etiology, incidence and sites of positive margins, the use of frozen sections to assess the margins and the relationship between margin positivity and prognosis. Issues relating to grade within the radical prostatectomy specimen are covered in depth, including novel ways of reporting Gleason grade and the concept of tertiary Gleason patterns. Tumor volume, tumor location, vascular invasion and perineural invasion are the final variables discussed relating to the prognosis of radical prostatectomy specimens. The use of multivariate analysis to predict progression is discussed, together with proposed modifications to the TNM system. Finally, biomarkers to predict progression following radical prostatectomy are described, including DNA ploidy, microvessel density, Ki-67, neuroendocrine differentiation, p53, p21, p27, Bcl-2, Her-2/neu, E-cadherin, CD44, retinoblastoma proteins, apoptotic index, androgen receptor status, expression of prostate-specific antigen and prostatic-specific acid phosphatase and nuclear morphometry.

Mucin-producing urothelial-type adenocarcinoma of prostate: report of two cases of a rare and diagnostically challenging entity

The differential diagnosis of mucin-producing adenocarcinoma of the prostate includes conventional prostatic adenocarcinoma with mucin production, secondary adenocarcinoma usually of colorectal origin and, very rarely, urothelial-type adenocarcinoma arising from either the prostatic urethra or proximal ducts. Conventional prostatic adenocarcinoma with mucin production is readily identified by routine microscopy and immunohistochemistry. The distinction between secondary adenocarcinoma and urothelial-type adenocarcinoma, however, can present a significant diagnostic challenge. In addition, documented examples of the latter in the prostate are exceptionally rare. A transurethral resection of prostate specimen and prostatic needle biopsies from two patients showing urothelial-type adenocarcinoma of the prostate were identified in our consultation files. One of the patients subsequently underwent a radical prostatectomy. Both patients had negative gastrointestinal endoscopic workups. Transurethral resection of prostate material from two patients with clinically confirmed secondary adenocarcinoma of colonic origin involving the prostate and a prostatectomy specimen with mucinous conventional prostatic adenocarcinoma were also identified for comparison purposes. Formalin-fixed, paraffin-embedded sections were stained for prostate-specific antigen (PSA), prostatic acid phosphatase, carcinoembryonic antigen, cytokeratin 7, cytokeratin 20 and high molecular weight cytokeratin 34betaE12. The urothelial-type adenocarcinoma cases were diffusely positive for cytokeratin 7 and focally positive for 34betaE12 and cytokeratin 20, consistent with an origin from the urothelium of the prostatic urethra or proximal prostatic ducts. In contrast, the secondary adenocarcinoma of colonic origin cases were diffusely cytokeratin 20 positive and either negative or focally positive for cytokeratin 7 and negative for 34betaE12. The mucinous conventional prostatic adenocarcinoma was positive for PSA and prostatic acid phosphatase and negative for cytokeratin 7, cytokeratin 20 and 34betaE12. All tumors were positive for carcinoembryonic antigen.

Basal Cell Proliferations of the Prostate Other Than Usual Basal Cell Hyperplasia

Basaloid proliferations of the prostate with morphologic patterns other than usual basal cell hyperplasia are rare, and the distinction between benign and malignant lesions has been difficult. We describe 23 such lesions and classify them into two groups: adenoid cystic-like hyperplasia and adenoid cystic or basaloid carcinoma. Adenoid cystic-like hyperplasia (n = 19) was characterized by an older age at presentation (mean, 71.8 years), transition zone location with background of nodular hyperplasia, multifocality, lobulation, circumscription, and small acini with occasional hyalinization. A cribriform pattern limited to small- and medium-sized glands, squamous metaplasia, and hypercellular myxoid stroma were occasionally seen. Adenoid cystic carcinoma (n = 3) was characterized by a younger age at presentation (mean, 46.0 years), peripheral zone involvement, and large acini that were often dilated and exhibited extensive interanastomoses, prominent intraglandular hyalinization, perineural invasion, and extraprostatic extension. Basaloid carcinoma (n = 1) showed infiltration between normal glands, perineural invasion, and extraprostatic extension but lacked a cribriform architecture. The degree of cytologic atypia and mitotic rate overlapped between the hyperplasia and carcinoma cases. Both hyperplastic lesions and adenoid cystic carcinomas showed a basal cell phenotype with strong immunoreactivity to cytokeratins 14 and 34betaE12, but the basaloid carcinoma was negative for these markers. In all cases, the proliferating basal cells were nonreactive for myoepithelial and prostatic secretory cell markers. The 8 patients with adenoid cystic-like hyperplasia with available follow-up information had no progression of disease (mean follow-up period, 8.6 years). One patient with adenoid cystic carcinoma died with widespread metastases, but the 3 other patients with carcinomas had no disease progression (mean follow-up period, 7.0 years). In conclusion, most florid basaloid proliferations of the prostate fall into one of two categories. In the first, there is a clear association with nodular hyperplasia (adenoid cystic-like hyperplasia) and, although cytologic atypia and mitoses may be seen, they are present within a lesion that retains an orderly, vaguely nodular (noninfiltrative) pattern. The second group of cases (adenoid cystic and basaloid carcinoma) shows a widespread, haphazard infiltrative growth pattern. This study suggests that adenoid cystic carcinomas are biologically indolent following prostatectomy but have a low risk of distant metastasis.

Benign mimickers of prostatic adenocarcinoma

The diagnosis of prostatic adenocarcinoma, especially when present in small amounts, is often challenging. Before making a diagnosis of carcinoma, it is prudent for the pathologist to consider the various benign patterns and processes that can simulate prostatic adenocarcinoma. A useful method of classifying benign mimickers is in relationship to the major growth patterns depicted in the classical Gleason diagram. The four major patterns are small gland, large gland, fused gland and solid. Most mimickers fit within the small gland category and the most common ones giving rise to false-positive cancer diagnosis are atrophy, post-atrophic hyperplasia, atypical adenomatous hyperplasia and seminal vesicle-type tissue. A number of other histoanatomic structures such as Cowper's gland, verumontanum mucosal glands, mesonephric glands and paraganglionic tissue may be confused with adenocarcinoma. Additionally, metaplastic and hyperplastic processes within the prostate may be confused with adenocarcinoma. Furthermore, inflammatory processes including granulomatous prostatitis, xanthogranulomatous prostatitis and malakoplakia may simulate high-grade adenocarcinoma. Atypical adenomatous hyperplasia (adenosis), a putative precursor of transition zone adenocarcinoma, has overlapping features with low-grade adenocarcinoma and may cause problems in differential diagnosis, especially in the needle biopsy setting. The pathologist's awareness of the vast array of benign mimickers is important in the systematic approach to the diagnosis of prostatic adenocarcinoma. Knowledge of these patterns on routine microscopy coupled with the prudent use of immunohistochemistry will lead to a correct diagnosis and avert a false-positive cancer interpretation.

Solutions must include the community hospitals

The authors of this commentary acknowledge that Academic Health Sciences Centres(AHSCs) will need to change, but they assert that the need for change and urgency are even more dramatic than presented by Lozon and Fox. While the AHSCs are likely to survive, their form and fabric are likely to change dramatically in the new order. Any solutions to the problems of the AHSCs have to include the community hospital stakeholders, especially the evolving regional teaching hospitals. This applies not only to patient care but also to the potential teaching and research (clinical trials) contributions of the community/regional players. There must also be more involvement by non-medical faculties in defining the vision, mission and values of the AHSC. Federal funding should be available not only to enhance the research activity of the AHSCs and the regional partners but also to provide the informatic linkages between players. Alternative funding programs for academic physicians along with enhanced productivity measures in areas of patient care, education and research are important in order to level the playing field not only with respect to remuneration but also with respect to other incentives such as recognition and promotion.

Leiomyosarcoma of urinary bladder following cyclophosphamide therapy: report of two cases

Leiomyosarcoma of urinary bladder is rare, although it is the most common mesenchymal tumor in adults. We report two cases of this tumor following cyclophosphamide therapy. The first case is from a 53-year-old man with Wegener's granulomatosis treated for 6 years with cyclophosphamide. He presented with painless hematuria, and the initial biopsy of the bladder tumor revealed a malignant spindle cell neoplasm. A final diagnosis of leiomyosarcoma was made on radical cystoprostatectomy. The second example is from a 21-year-old man who had received cyclophosphamide in early infancy for a bilateral retinoblastoma. He also presented with painless hematuria, and a bladder tumor was resected transurethrally and diagnosed as leiomyosarcoma. He underwent partial cystectomy two months later. Cyclophosphamide, when used for a neoplastic or non-neoplastic condition, is associated with an increased risk of developing bladder cancer. The distribution of histologic subtypes differs from that seen in spontaneous bladder tumors. A review of the literature shows an increased proportion of squamous cell carcinomas and sarcomas, especially leiomyosarcomas in cyclophosphamide exposed patients. Acrolein, a cytotoxic metabolite of cyclophosphamide excreted in urine, is regarded as the most likely causative agent.

Inflammatory myofibroblastic tumors of the kidney: a clinicopathologic and immunohistochemical study of 12 cases

Inflammatory myofibroblastic tumor is a rare entity composed of spindle cells admixed with variable amounts of extracellular collagen, lymphocytes, and plasma cells. In the genitourinary tract, inflammatory myofibroblastic tumor most commonly occurs in the bladder. Isolated case studies of inflammatory myofibroblastic tumor of the kidney, renal pelvis, and ureter have been previously reported. Our series includes 12 cases of inflammatory myofibroblastic tumor occurring in the renal pelvis (six cases), renal parenchyma (four cases), and immediate perirenal soft tissue (two cases). Clinical presentation included flank pain (two patients), painless gross hematuria (one patient), and ureteropelvic junction stenosis with hydronephrosis (one patient). The remaining eight patients were asymptomatic. All patients underwent nephrectomy. The tumors were characterized by firm white tissue or had a myxoid "gelatinous" appearance. Three histologic patterns were identified in the tumors, including a myxoid vascular pattern, a compact spindle cell pattern, and a hypocellular fibrous pattern. Immunohistochemical and electron microscopic studies supported a myofibroblastic proliferation. All cases were negative for anaplastic lymphoma kinase. Follow-up was available in eight cases and ranged from 1 to 17 years with no evidence of recurrence. Based on this series, renal inflammatory myofibroblastic tumor is a proliferative lesion of myofibroblasts of uncertain pathogenesis with no identified potential for recurrence or metastases.

Pathologic effects of neoadjuvant cyproterone acetate on nonneoplastic prostate, prostatic intraepithelial neoplasia, and adenocarcinoma: a detailed analysis of radical prostatectomy specimens from a randomized trial

Neoadjuvant hormonal therapy (NHT; androgen ablation) is used prior to radical prostatectomy (RP) in an attempt to pathologically "downstage" prostatic adenocarcinoma and ultimately to improve disease-free survival. This study describes the pathologic effects of NHT with the antiandrogen cyproterone acetate, 300 mg/day for 12 weeks, on the RP specimens from men with clinically localized (stage T1 or T2) prostatic adenocarcinoma. There were 101 men in the pretreatment group (CPA) and 91 men in a control group who were treated with surgery alone. The prevalence and extent of morphologic effects were recorded for the nonneoplastic prostate, high-grade prostatic intraepithelial neoplasia, and invasive adenocarcinoma. The commonest effects on the nonneoplastic prostate were atrophy and basal cell hyperplasia and prominence. High-grade prostatic intraepithelial neoplasia was more commonly identified in the surgery alone group than the CPA group (p <0.01). In the CPA group, flat and low tufted patterns of high-grade prostatic intraepithelial neoplasia predominated. Following NHT, the adenocarcinoma showed characteristic morphologic alterations, including reduction in cytoplasmic quantity, cytoplasmic vacuolation, nuclear pyknosis, reduced gland diameter, and mucinous breakdown. In many cases there was prominence of collagenous stroma, obscuring malignant glands. Compared with the surgery alone group, the CPA group RP specimens had a significantly lower mean specimen weight (40.3 g vs 46.5 g, p = 0.025) and less tumor extent by several measures. Organ-confined tumor (stage pT2, margin negative) was found in 41.6% of the CPA group compared with 19.8% of the surgery alone group (p = 0.0017). The overall rate of margin positivity was lower in the CPA group (27.7% vs 64.8%, p = 0.001). We consider that the difference in margin positivity is the result of tumor shrinkage with a decreased likelihood of sampling in routine sections. There was no significant difference in the rate of extraprostatic extension between the two groups. There was elevation of the Gleason score in the RP specimens versus baseline biopsy in 60% of the CPA group compared with 33% of the surgery alone group (p = 0.02). The higher rate of elevation in the CPA group largely resulted from an increase in primary or secondary Gleason score 5 tumor, a morphologic artifact introduced by NHT. Because of this, we recommend not giving a Gleason grade to RP specimens following NHT. Monotherapy with CPA has similar pathologic effects on benign and malignant prostate tissue as does dual agent androgen blockade. Prolonged follow-up of these patients is required to determine if NHT with CPA leads to improved disease-free survival.

Leydig cell tumors of the testis with unusual features: adipose differentiation, calcification with ossification, and spindle-shaped tumor cells

We report 19 Leydig cell tumors (LCTs) of the testis with adipose differentiation (n = 12) and/or spindle cell growth (n = 8) in patients 28-70 years of age; three tumors with adipose differentiation showed psammomatous calcifications, two of which also had foci of ossification. In eight tumors fat-like cells apparently derived from lipid accumulation within neoplastic Leydig cells and appeared as focal to prominent clusters in a background of vacuolated, neoplastic Leydig cells. The fat-like cells were usually immunoreactive for Leydig cell markers (inhibin-alpha, calretinin, and melan-A) but were typically strongly positive for the adipose tissue marker, S-100 protein, supporting a hybrid cell phenotype. Four tumors had fat of stromal derivation. In two of these there were intermixed mature adipocytes, but in two others only lipoblastic cells were present. These four tumors lacked vacuolated, neoplastic Leydig cells, and the fat cells in the single case studied were negative for inhibin-alpha and melan-A but positive for S-100. Three of the 12 LCTs with adipose differentiation were clinically malignant, and each had several of the established malignant features. Eight tumors with spindle cells occurred in men 34-70 years of age. Two tumors had ill-defined fascicles of spindle cells, and three showed prominent edematous to myxoid areas with spindle-shaped tumor cells. Two additional tumors had a fibroma-like spindled component that blended with islands of more plump, polygonal to spindle-shaped Leydig cells. Finally, one tumor had foci resembling an unclassified sarcoma that merged with conventional LCT; the spindle cell component in this case did not react for Leydig cell markers in contrast to the spindle cells in five of the six other cases in which immunostains were performed. Spindle cell differentiation, by itself, did not appear to have prognostic significance. Of the six patients with available follow-up, two developed metastases, but their tumors had malignant features apart from spindle cells; the remaining four patients were disease free at a mean of 3.6 years. Awareness of these unusual patterns in LCTs may prevent misinterpretation of fat admixed with neoplastic Leydig cells as evidence of extratesticular growth (a criterion for malignant LCT) may help avoid misdiagnosis of a LCT as a testicular "tumor" of the adrenogenital syndrome (which may contain fat) and may prevent misdiagnosis of a LCT with spindle cells as a sarcoma or unclassified sex cord-stromal tumor.

Pigmented pseudotumor of the testis: a unique testicular and para-testicular mass

We report on the case of a 24 year old male with a testicular and paratesticular melanin-like, pigmented lesion. This is the first report of this type of lesion which we have designated a pigmented pseudotumor.

Dermoid cyst of the testis: a study of five postpubertal cases, including a pilomatrixoma-like variant, with evidence supporting its separate classification from mature testicular teratoma

It is controversial if the rare dermoid cyst of the testis should be classified as a variant of mature teratoma or separately. The spectrum of findings is also ill defined, as is the relationship of dermoid cyst to intratubular germ cell neoplasia of the unclassified type (IGCNU). This study therefore reports the findings in five testicular dermoid cysts that occurred in five patients, 17-42 years of age, who presented with testicular masses. Four lesions consisted of a keratin-filled cyst with a thickened wall, whereas one had islands of "shadow" squamous epithelial cells with superimposed calcification and ossification (pilomatrixoma-like variant). Hair was identified grossly in two cases. On microscopic examination, four tumors had hair follicles with sebaceous glands showing a typical, cutaneous-type orientation to an epidermal surface, although no hair shafts were present in two. In addition, the fibrous wall contained smooth muscle bundles (all tumors) and eccrine or apocrine sweat glands (4 tumors). In some cases there were also glands lined by ciliated epithelium (4 tumors, including the pilomatrixoma-like variant), intestinal mucosa (1 tumor), and bone (2 tumors). There was no cytologic atypia or apparent mitotic activity, and no case had IGCNU in the seminiferous tubules. All patients were clinical stage I and were treated by orchiectomy without adjuvant therapy. All were well on follow-up from 1.5 to 9.5 years later. This study supports that dermoid cyst may have noncutaneous teratomatous elements and that an important criterion for its diagnosis is the absence of IGCNU. It also supports that it should be categorized separately from mature testicular teratoma because of the malignant nature of the latter in postpubertal patients. These observations suggest that there are at least two pathways for testicular teratomas in postpubertal patients: the more common being through IGCNU by differentiation from an invasive malignant germ cell tumor and the less common one, taken by dermoid cyst, by direct transformation from a nonmalignant germ cell.

Primary extrapulmonary sugar tumor (PEST): a report of four cases

The cell of origin and direction of differentiation of the clear cell tumor of the lung (the so-called sugar tumor) remains enigmatic. Recognition of HMB-45 immunoreactivity and identification of melanosomes have suggested a relationship to angiomyolipoma of kidney or liver and lymphangiomyoma. This has given rise to the concept that clear cell tumors are neoplasms of so-called perivascular epithelioid cells--PEComas. Herein we report the existence of four similar tumors occurring in extrapulmonary sites, one of which had malignant features. The three benign tumors occurred in females ages 9, 20, and 40 years; two were located in the rectum and one in the vulva. The malignant tumor occurred in the inter-atrial cardiac septum of a 29-year-old man. Common histologic features were a richly vascular organoid architecture, tumor cells with clear to pale eosinophilic cytoplasm, abundant glycogen, and immunoreactivity for HMB 45, but not S100, multiple keratin, neuroendocrine, or muscle markers. Benign tumors demonstrated low mitotic activity, no necrosis, and good circumscription; the malignant tumor showed considerable mitotic activity, necrosis, and an infiltrative growth pattern. Ultrastructurally, glycogen was present, mitochondria were abundant, and membrane-bound lamellated bodies consistent with premelanosomes were present in two cases, and equivocal in one. Because these tumors have light microscopic, immunohistochemical, and electron microscopic features similar to pulmonary sugar tumors, we propose the name primary extrapulmonary sugar tumor (PEST) for them. Although most PEST's are probably benign, malignant forms appear to exist. These cases further support the concept of a family of systemic HMB-45 positive tumors that include sugar tumors, angiomyolipoma of kidney or liver, lymphangiomyomas, and clear-cell myomelanocytic tumors of the falciform ligament/ligamentum teres.

Mixed epithelial and stromal tumor of the kidney lacks the genetic alterations of cellular congenital mesoblastic nephroma

Mixed epithelial and stromal tumor of the kidney is a recently recognized neoplasm that occurs almost exclusively in perimenopausal women. Because it frequently contains areas of smooth muscle in which epithelial structures are embedded, some have concluded that it is the adult form of congenital mesoblastic nephroma. Others have concluded that the morphology and epidemiology of mixed epithelial and stromal tumor indicate that it is unrelated to congenital mesoblastic nephroma. Although the genetic alterations of mixed epithelial and stromal tumor have not been previously elucidated, much is known about the genetic alterations of cellular congenital mesoblastic nephroma. The present study was undertaken to determine if mixed epithelial and stromal tumors have any of the genetic alterations recognized as typical of cellular congenital mesoblastic nephroma. RNA extraction was performed on formalin-fixed, paraffin-embedded tissue from 7 mixed epithelial and stromal tumors followed by reverse-transcription polymerase chain reaction to detect the ETV6-NTRK3 gene fusion. Fluorescent in situ hybridization with centromere-specific probes for chromosomes 8, 11, and 17 was performed to evaluate polyploidy of these chromosomes in 11 cases of mixed epithelial and stromal tumor. None of the mixed epithelial and stromal tumors showed any of these genetic alterations. We conclude that mixed epithelial and stromal tumor of the kidney lacks the genetic alterations typical of cellular congenital mesoblastic nephroma, is unrelated to it, and the appellation "adult mesoblastic nephroma" should not be used for these tumors.