Radical prostatectomy (RP) specimens are usually transported in buffered 4 % formaline saline, occasionally, fresh tissue is harvested in the laboratories for research reasons. However, is has been pointed out that the specimens should be placed in fixative as soon as possible, because of alteration in protein, DNA or RNA confirmation that must be satisfactory for the preservation of microscopic and IHC features [18]. The histological diagnosis of PCa is based on formalin fixed and paraffin embedded tissue. The initial diagnosis is based on needle biopsies, usually four or more biopsies from each patient. Prognosis after RP relies, in part, on accurate characterization of a number of histological features, including the status of the surgical margin, extra prostatic tumor growth, Gleason grade, tumor volume and whether tumor extends into the seminal vesicles and/or is metastatic to regional lymph nodes. The 2009 International Society of Urological Pathology Consensus Conference in Boston made recommendations regarding the standardization of pathology reporting of RP specimens [19, 20]. The use of whole mounts of sections from RP specimens has the advantage of displaying the whole architecture of the prostate and the location of tumor areas. Of most importance is assessment of free resection margins, therefore painting the surfaces gives more precise information about the margins [19, 20]. Separate histological examination of both apex and base should be prepared by cutting sagittal sections of the conus (Fig. 9.2) [19]. Histological examination of tumor tissues in prostatic apex and base predicts outcome [21].

Positive lymphatic involvement is generally considered as a poor prognostic indicator and has impact on treatment options [22]. Identifying lymphatic involvement requires accurate nodal staging. Some laboratories report enhanced retrieval of lymph nodes using Glacial acetic acid, ethanol, distilled water, and formaldehyde (GEWF), compared to formalin fixed specimens [23].

The Gleason grading system is so far the most commonly used system for histological characterization of prostate cancer, and it’s the most powerful predictor of outcome for PCa patients [23]. Gleason grading depends solely on architectural patterns of the tumor. The grade is defined as the sum of the two most common grade patterns and reported as the Gleason score. Both the primary (predominant) and the secondary (second most prevalent) architectural patterns are identified and assigned a number from 1 to 5, were 1 being the most differentiated and 5 the least differentiated pattern [23]. Since the introduction of the Gleason grading system more than four decades ago many aspects of prostate cancer have changed, including PSA testing, transrectal ultrasound guided prostate needle biopsies with sampling and immunohistochemistry for identification of basal cells. These techniques have changed the classification of prostate cancer and led to identification of new prostate cancer variants. Gleason grading system was updated in 2005 by experts in urological pathology at a consensus conference held by the International Society of Urological Pathology (ISUP). This has resulted in a more accurate grading system in both needle biopsies and RPs [24–27]. This modified system has also led to a better correlation between pathological stage, rate of positive margins, and biochemical recurrence with Gleason scores. Still, Gleason score is the only independent predictor of metastatic disease [28].^. The main differences between the original system and the 2005 ISUP Modified Gleason grading system are summarized in Table 9.1 [24, 26, 27, 29].

The pTNM-classification is currently under revision. Within category pT2 PCa, a wide variation in tumor extent may be seen, which varies from single microscopic lesions to large volume multifocal tumors, often involving both sides of the prostate. This heterogeneity of tumor volume of pT2 prostate cancers and the potential impact on prognostic assessment has resulted in attempts to subcategorize organ-confined tumors. In TNM 2002, pT2 was substaged in pT2a (tumor involves one half of one lobe or less), pT2b (tumor involves more than half of one lobe, but not both lobes), and pT2c (tumor involves both lobes). In the TNM 2010 staging, the pathological substaging of pT2 prostate cancers has been retained, although the prognostic value of this has been questioned.

The 2009 ISUP consensus conference in Boston made recommendations that the standardization of T2 substaging should be optional. Although, there was an overall agreement that the current pT2 substaging should not be used, there was no consensus what sort of substaging should replace it [30–33].

Early detection of PCa through PSA screening has resulted in detection of men with PCa at earlier stages and with lower Gleason grade, but has also contributed to concerns about overdiagnosis and overtreatment of clinically insignificant disease. As a single test serum PSA has limitations, because some men with very low serum levels of PSA (<4.0 ng/ml) will develop prostate cancer (~15 %) [13], and men with benign conditions including BPH, prostatitis and medical intervention frequently elevate serum PSA. This makes serum PSA more sensitive than specific for PCa. However serum PSA is of great value in disease monitoring of existing cancer and for identification of recurrent disease after treatment. Among men undergoing radical prostatectomy, the persistence of undetectable serum levels of PSA can be used to confirm absence of recurrent disease.

In order to react against a tumor, the immune system must have antigens that are recognized as foreign. A number of alterations in gene expression occur in cells during tumorigenesis. Tumorigenesis may lead to expression of new antigens or alteration in existing antigens that are found in normal cells. These antigens may include membrane receptors, regulators of cell cycle and apoptosis, or molecules involved in signal transduction pathways. In PCa, AMACR, is a mitochondrial and peroxisomal enzyme that is involved in bile acid biosynthesis and beta-oxidation of branched-chain fatty acids. AMACR is overexpressed in PCa epithelium, making it a specific marker for cancer cells within the prostate gland. Furthermore, overexpression of AMACR is found in premalignant lesions like HGPIN, may increase PIN, may increase the risk of PCa. I addition, genome-wide scans for linkage in hereditary PCa families suggest that the chromosomal region for AMACR (5p13) is the location of a PCa susceptibility gene. Also, experimental studies have shown that loss of AMACR expression slows the growth of some PCa cell lines. As a biomarker AMACR is of important value in PCa.

The prognosis and treatment decisions are mainly based on pathological criteria, and proper staging is highly dependent on good quality biopsies. Approximately 70 % of these tumors are papillary and confined to the urothelial mucosa (stage Ta) or to lamina propria (T1), whereas, the remaining invade the muscle (T2), the perivesical fat (T3) or surrounding organs (T4) (Fig. 9.3). Favorable prognostic factors for superficial TCC at stage Ta, compared to stage T1 are: low grade and no dysplasia, whereas high grade, tumor multiplicity, tumor size greater than 5 cm, and vascular invasion increase the risk for tumor progression.

TCC (urothelial carcinoma) can rise anywhere in the bladder. They are defined according to their histologic characteristics and so far, histologic examination is the most specific method for assessing these lesions [37]. The pattern of growth may be exophytic or endophytic or a combination of both. When histologically exophytic, the tumor may adopt a papillary configuration with a fibrovascular core, or a solid nodular appearance. The latter may result in clusters of tumor cells in the lamina propria. Stromal invasion of TCC proceed in two stages: invasion of the lamina propria and invasion of the muscle layer. The detection of muscle invasion is of great consequence, because of the influence on therapy and prognosis. Histological diagnose of early bladder cancer (superficial TCC) or non-muscle invasive bladder cancer, which includes papilloma (benign lesions), papillary urothelial neoplasms with low malignant potential (PUNLMP), Low grade papillary carcinomas CIS (TIS/CIS), is virtually never confused with high grade carcinomas. PUNLMP have many features in common with normal epithelium and the histologic feature of the cells on the stalks is preserved and the nuclear feature are only slightly abnormal [38]. Lacking significant nuclear pleomorphic appearance, PUNLMP cells are difficult to recognize in urinary samples. However, this entity is considered as neoplastic because they tend to recur in the same site, and if left untreated, they can grow and dedifferentiate into aggressive cancers. Urothelial carcinoma, low grade, is a predominantly papillary urothelial neoplasm which resembling PUNLMP features. Histologically, the superficial layer is preserved, and the cells are uniform in size and evenly distributed. The orientation of the nuclei are often normal, but are rounded and slightly pleomorphic. There distinction of PUNLMP from low grade carcinomas may be difficult. However, the cells of low grade carcinoma are smaller and more densely arranged on the fibrovascular stalks, than the cells of PUNLMP, and at high magnification, there is a slight degree of nuclear pleomorphism and the nuclear chromatin is finely granular and evenly distributed. Immunohistochemical analyses are unlikely to be helpful in the differential diagnosis. The tumor cells are typically uniform, but densely packed in tissue sections. The tumor cells have indistinct borders, little or no cytoplasm, and the nuclear are pleomorphic, and the nuclear borders are irregular with coarse and uneven chromatin structure. Almost all invasive urothelial neoplasms are high grade, at least there is a focus of invasion, whether the invasion is confined to the lamina propria or muscularis propria. Mitoses are common and may be abnormal. Differential diagnostic problems are not a large problem, but may raise when high TCC involve prostatic duct or when prostatic carcinomas have invaded the bladder base. However, there are histological differences between high grade TCC and prostate cancer cells. Of importance is to diagnose patients whom superficial tumors are less differentiated, large, multiple, or associated with CIS in other areas of the bladder mucosa. These patients are at great risk for recurrence and the development of invasive cancers. IHC is overall of limited value when reactions for cytokeratins (7 and 20), carcinoembryonic antigens (CEA)125, 34β[beta]E12, and thrombomodulin are not specific. However, cytokeratins (CK20, CK7), tumor suppressor gene (p53) and the proliferation marker, Ki67 is widely used, because the majority of urothelial carcinomas are CK7+/CK20/CEA125-. The expression of CK20 is restricted to superficial ‘umbrella’ cells and occasional in the intermediate cells in benign and reactive urothelium, and also in severe inflammation. In dysplasia and CIS there is usually a complete or at least focal loss of this cellular reaction in all layers of the urothelium [39]. CK20/CK7 positivity may be useful when both were positive, supporting the diagnose of urothelial cancer. However, if only one marker was positive, or both negative, these markers have limited usefulness for distinguish these carcinomas. Expression of p53 has also been associated with an adverse prognosis for patients with invasive bladder cancer. Retrospective studies have shown that presence of nuclear p53 is an independent predictor for recurrence among patients with T-1-T3 tumors [40–43].