This special section attempts to provide a comprehensive update of genitourinary tumors and their precursor lesions highlighting recent new knowledge and development in a diagnostic and clinical context. Tumors of the genitourinary tract, whether benign, malignant, or precursor conditions, are collectively responsible for significant morbidity and mortality in men and women of all ages throughout the world. In the United States, prostate cancer is the leading noncutaneous cancer in men, accounting for 33% of all cancers, and urinary bladder and kidney cancers account for 7% and 3% of all cancers in men, respectively. In women, the incidence of bladder and kidney cancers is less common than that in men but still accounts for 2% and approximately 2% of all cancers in women, respectively.1 Recent advances in understanding of the molecular and genetic basis of cancer and development of a variety of modern techniques such as immunohistochemistry, cytogenetics, fluorescent in situ hybridization, nucleic acid array, and so forth allow identification of new neoplastic entities as well as better classification of neoplasms that are biologically and clinically relevant.In this issue, we cover 4 specific topics: (1) newly described and recently emphasized entities of renal tumors, (2) histologic variants of infiltrating urothelial carcinoma, (3) prostatic intraepithelial neoplasia (PIN): recent advances, and lastly (4) recent advances in germ cell neoplasms of the testis.In the first subject on newly described and recently emphasized entities of kidney tumors, the authors focus on the most important renal tumors that have been recently defined or emphasized with a brief introduction of the new World Health Organization renal cancer classification.2 The clinical, gross, microscopic, and immunohistochemical features of these tumors are reviewed as well as their relevant cytogenetic and molecular abnormalities. Important differential diagnoses of each of these entities and helpful morphologic features are emphasized. Recognition and awareness of these entities becomes important as some of them have different biologic behavior and treatment strategies.The second subject is histologic variants of infiltrating urothelial carcinoma. The authors focus on the diagnostic problems of infiltrating urothelial carcinoma with emphasis on several important morphologic variants as recognized by the recent World Health Organization classification system.2 Some of these variants are important to recognize because of their unique biologic behavior, different prognosis, or response to therapy. Other morphologic variants exhibit deceptive or subtle histologic features creating diagnostic difficulties for pathologists. Familiarity with the diverse morphologic spectrum of urothelial carcinoma is not simply an academic exercise but is important in providing high-quality care for patients affected by this disease. For each variant of urothelial carcinomas, the characteristic morphologic and salient clinical features and important differential diagnoses are reviewed.The third subject, PIN: recent advances, deals with the morphologic aspects of this well-proven preneoplastic condition. Patterns and diagnostic criteria of PIN, as well as differential diagnoses, are discussed. It is well established that a spatial and temporal relationship exists between high-grade PIN and prostatic acinar adenocarcinoma. Furthermore, high-grade PIN and prostate cancer share similar genetic and molecular changes as well. Thus, high-grade PIN remains a precancerous condition with a high risk for the development of carcinoma or a marker for concurrent carcinoma. With the widespread use of prostatic-specific antigen screening and extended biopsy protocols, there is an increasing number of patients with diagnoses of high-grade PIN that are not showing invasive carcinoma on repeated biopsies. Therefore, the management of patients with PIN is shifting toward a more conservative approach. Atypical adenomatous hyperplasia (adenosis) is no longer considered a premalignant lesion but rather a benign small glandular process of the transition zone that simulates acinar adenocarcinoma and as such is not discussed here.The last subject is recent advances in germ cell neoplasms of the testis. In this review, the authors summarize the current understanding of testicular germ cell neoplasms and their relationship with in situ neoplasia. Testicular germ cell tumors are a heterogeneous group of neoplasms with a diverse histopathology and different behavior and prognosis. The recent World Health Organization classification of testicular neoplasms2 as well as important diagnostic features of each entity are discussed including several newly developed immunohistochemical markers.It is our sincere hope that this review will provide the readers a concise and quick reference for the recent advances and development of these 4 selective topics of genitourinary tumor pathology. Each mini-review emphasizes the important morphologic features and their clinical relevance. Awareness of these entities and new advances will enable pathologists and pathology trainees to strengthen their diagnostic abilities and to acquire a better understanding of the pathogenesis of these processes, which will lead to better communication with clinicians and will develop common language for the treatment and follow-up of patients.
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Oct 10, 2007
D Maeda + 5
Open Access
