Primary signet ring cell carcinoma of the prostate: report and review of 42 cases

Primary signet ring cell carcinoma of prostate: A rare case report and review of literature

Primary signet ring cell carcinoma (PSRCC) of the prostate is an extremely rare variant of prostatic adenocarcinoma. A PubMed search of the English language literature from January 2000 to June 2020 using the keywords "signet ring cell carcinoma" and "prostate," identified 20 cases of PSRCC of the prostate. On the basis of the combined data from this study and the literature review, 21 such patients were evaluated for clinical characteristics, histologic diagnoses, special and immunohistochemical staining, and treatment. The mean age at the diagnosis was 68.47 years (range 50-85 years). The prostate-specific antigen (PSA) levels varied from 0.19 to 6658 ng/mL, with a mean of 509.15 ng/mL. Most (50%) presented with Stage 3 cancer. The most common Gleason grade group was 5 (Gleason score 9 to 10), seen in 61.5%. The extent of signet ring cell involvement of the specimen when reported was documented as more than 20% of the tumor-containing signet ring cells, with a range of 25%-90%. For pathologic diagnosis, the most common special stains performed were periodic acid-Schiff and Alcian blue, and among the immunohistochemical stains, the most common were PSA, CK20, and prostate-specific acid phosphatase. A detailed clinicoradiological and pathological workup is essential to rule out primary from other common sites, in view of its grave prognosis and lack of an established treatment protocol.

A Case of Prostatic Signet-Ring Cell-like Carcinoma with Pagetoid Spread and Intraductal Carcinoma and Long-Term Survival: PD-L1 and Mismatch Repair System Proteins (MMR) Immunohistochemical Evaluation with Systematic Literature Review

Prostatic adenocarcinoma (PA) is the second most common malignancy in men globally. Signet-ring cell-like adenocarcinoma (SRCC) is a very rare PA subtype, with around 200 cases reported in the English literature. Histologically, the tumor cells show a vacuole compressing the nucleus to the periphery. Pagetoid spread in acini and ducts is usually related to metastases from urothelial or colorectal carcinomas, less commonly associated with intraductal carcinoma (IC); histologically, the tumor cells grow between the acinar secretory and basal cell layers. To our knowledge, we report the first prostatic SRCC (Gleason score 10, stage pT3b) associated with IC and pagetoid spread to prostatic acini and seminal vesicles. To our systematic literature review (PRISMA guidelines), it is the first tested case for both PD-L1 (<1% of positive tumor cells, clone 22C3) and mismatch repair system proteins (MMR) (MLH1+/MSH2+/PMS2+/MSH6+). We found no SRCC previously tested for MMR, while only four previous cases showed high expression of another PD-L1 clone (28-8). Finally, we discussed the differential diagnoses of prostatic SRCC.

The 2022 World Health Organization Classification of Tumors of the Urinary System and Male Genital Organs-Part B: Prostate and Urinary Tract Tumors

The 2022 World Health Organization (WHO) classification of the urinary and male genital tumors was recently published by the International Agency for Research on Cancer. This fifth edition of the WHO "Blue Book" offers a comprehensive update on the terminology, epidemiology, pathogenesis, histopathology, diagnostic molecular pathology, and prognostic and predictive progress in genitourinary tumors. In this review, the editors of the fifth series volume on urologic and male genital neoplasms present a summary of the salient changes introduced to the classification of tumors of the prostate and the urinary tract.

Primary prostatic signet ring cell carcinoma in elderly with obstructive uropathy: a case report

Background

Primary signet-ring cell carcinoma (SRCC) of the prostate is a rare and aggressive subtype of prostate adenocarcinoma with a poor prognosis, with only approximately 60 cases reported worldwide.

Case presentation

A 62-year-old man presented with acute urinary retention and hematuria, after a year’s history of lower urinary tract symptoms. Digital rectal examination revealed an irregular and hard prostate. Flexible cystoscopy showed bladder base infiltration by the enlarged prostate obscuring both ureteric orifices, necessitating nephrostomy and subsequent bilateral antegrade stenting to relieve the obstruction and improve his renal function. Transrectal ultrasonography biopsy of the prostate was performed revealing histological features of SRCC. Due to its rarity, there is currently no standardized treatment approach and it is often similarly treated according to the traditional management of prostate adenocarcinoma.

Conclusions

SRCC of the prostate is a rare and aggressive subtype of acinar adenocarcinoma with no established guidelines. Histological criteria for SRCC of the prostate are highly variable in the available literature. It is important to differentiate between the primary and metastatic SRCC of the prostate as both are managed differently. However, the overall prognosis remains poor in general.

Diagnosis and Management of Primary Prostatic Signet Ring Cell Carcinoma: Single-Center Experience

The purpose of the study was to retrospectively summarize the diagnosis and management of 10 primary prostatic signet ring cell carcinoma (PPSRCC) cases in our center. Ten PPSRCC patients diagnosed at the First Affiliated Hospital of Nanjing Medical University from November 2014 to December 2020 were included. Clinical characteristics, image features, therapeutic procedures, histological diagnosis, and outcomes were retrospectively analyzed. All patients received prostate-specific antigen (PSA) examination preoperatively. Nine of them accepted multiparametric magnetic resonance imaging (mpMRI) due to elevated PSA value, and further biopsied. Among them, five patients were diagnosed as prostatic adenocarcinoma and the other four cases were found a mixture of signet ring cell carcinoma (SRCC) and adenocarcinoma. Furthermore, gastrointestinal endoscope and abdominal computed tomography (CT) did not find SRCC originating in gastrointestinal tract. Therefore, these cases were considered to be PPSRCC. Nine patients accepted laparoscopic or robot-assisted RP. Only one patient with normal PSA adopted transurethral resection of the prostate. Postoperative pathological results confirmed SRCC mixed with prostatic adenocarcinoma in nine cases, and only one patient with pure SRCC. After surgery, nine patients received adjuvant hormone therapy, one of which accepted radiotherapy simultaneously. The patient with pure SRCC did not accept any adjuvant therapy postoperatively. During a mean follow-up of 31.9 months, only four patients were alive without disease progression. In summary, PPSRCC is a rare malignant tumor with few specific symptoms, rapid disease progression, and poor prognosis and is frequently accompanied by high-grade prostate adenocarcinoma patterns. There is still no clear and effective strategy to improve the prognosis.

Epidemiology of Signet Ring Cell Adenocarcinomas

Signet ring cell adenocarcinomas (SRCCs) are a rare histological subtype of adenocarcinomas with a poor prognosis, typically due to advanced disease at diagnosis. A signet ring cell, mimicking its moniker, contains abundant intracytoplasmic mucin that pushes the nucleus to the periphery. In these cancers, this cell feature comprises more than 50% of the tumor. Despite predilection for the gastrointestinal tract, and in particular the stomach, primary SRCCs are also described in other sites, typically in case reports. This literature, however, lacks a standardized overview of the SRCC disease entity. Using a retrospective cohort approach, we summarize the clinicodemographic and mortality outcomes of SRCCs in thirteen primary sites, comprising 95% of all SRCCs in the Surveillance, Epidemiology, and End Results Program (SEER), a population-level cancer database covering nearly one-third of the United States population. SRCCs general trends compared to matching nonvariant adenocarcinomas are earlier age of onset, with initial presentation favoring higher rates of regional or distant disease presentation and poor tumor differentiation. After multivariable analysis, SRCCs typically have worse overall survivals, but substantial variances exist depending on tumor location. Identifying SRCCs at earlier disease stages is likely the single most important intervention to improving outcomes for these patients.

The Impact of Epidemiological Factors and Treatment Interventions on Survival in Patients With Signet Ring Cell Carcinoma of the Pancreas

OBJECTIVES

Primary pancreatic signet ring cell carcinoma (SRCC) is a rare histologic variant of pancreatic carcinoma. A population-based analysis of pancreatic SRCC was performed to determine the predictive effects of epidemiological factors and treatment interventions on overall survival (OS) and disease-specific survival (DSS).

MATERIALS AND METHODS

The Surveillance, Epidemiology, and End Results registry was searched for pancreatic SRCC cases diagnosed between January 1, 1973 and December 31, 2013. Statistical analysis was performed using the Fisher exact test, χ(2) analysis, Kaplan-Meier method, log-rank test, and Cox proportional hazards regression.

RESULTS

The mean age among 497 patients was 66.6 years (SD, 11.9). Most patients were white (82.7%) and male (54.5%). The 1-, 2-, and 5-year OS rates were 17%, 9%, and 4%, respectively, while the corresponding 1-, 2-, and 5-year rates for DSS were 18%, 10%, and 5%, respectively. On univariable analysis; age, site, grade, stage, and treatment were predictive of OS and DSS (P<0.05). On multivariable analysis; radiation improved OS and DSS (adjusted hazard ratio [aHR], 0.592 and 0.589, respectively), pancreatectomy improved OS and DSS (aHR, 0.360 and 0.355, respectively), and combination therapy improved OS and DSS (aHR, 0.295 and 0.286, respectively). Age, site, and stage were also independent predictors of OS and DSS. Subgroup analysis demonstrated treatment to be an independent predictor of OS and DSS in localized/regional disease, in distant disease, and in patients diagnosed between 2000 and 2013.

CONCLUSIONS

Age, site, stage, and treatment independently predict OS and DSS in pancreatic SRCC.

Signet-Ring Cell Carcinoma Presenting as Hematochezia in a Patient with Crohn's Disease

Signet-ring cell carcinoma is a rare adenocarcinoma, predominantly affecting the stomach and ovaries. Primary sites elsewhere are rarer. It is recognized that there is an increased cancer risk with the diagnosis of Crohn's disease. We report a patient with Crohn's disease who was diagnosed with signet-ring cell carcinoma in the setting of a Crohn's flare. Diagnosis was made with endoscopy. Treatment included laparoscopic-assisted right hemicolectomy with ileostomy with subsequent chemotherapy as an outpatient.

Deletion of the p16INK4a tumor suppressor and expression of the androgen receptor induce sarcomatoid carcinomas with signet ring cells in the mouse prostate

The tumor suppressor p16^Ink4a, encoded by the INK4a gene, is an inhibitor of cyclin D-dependent kinases 4 and 6, CDK4 and CDK6. This inhibition prevents the phosphorylation of the retinoblastoma protein (pRb), resulting in cellular senescence through inhibition of E2F-mediated transcription of S phase genes required for cell proliferation. The p16^Ink4a plays an important role in tumor suppression, whereby its deletion, mutation, or epigenetic silencing is a frequently observed genetic alteration in prostate cancer. To assess its roles and related molecular mechanisms in prostate cancer initiation and progression, we generated a mouse model with conditional deletion of p16^Ink4a in prostatic luminal epithelium. The mice underwent oncogenic transformation and developed prostatic intraepithelial neoplasia (PIN) from eight months of age, but failed to develop prostatic tumors. Given the prevalence of aberrant androgen signaling pathways in prostate cancer initiation and progression, we then generated R26hAR^L/wt:p16^L/L: PB-Cre4 compound mice, in which conditional expression of the human AR transgene and deletion of p16^Ink4a co-occur in prostatic luminal epithelial cells. While R26hAR^L/wt:PB-Cre4 mice showed no visible pathological changes, R26hAR^L/wt:p16^L/L: PB-Cre4 compound mice displayed an early onset of high-grade PIN (HGPIN), prostatic carcinoma, and metastatic lesions. Strikingly, we observed tumors resembling human sarcomatoid carcinoma with intermixed focal regions of signet ring cell carcinoma (SRCC) in the prostates of the compound mice. Further characterization of these tumors showed they were of luminal epithelial cell origin, and featured characteristics of epithelial to mesenchymal transition (EMT) with enhanced proliferative and invasive capabilities. Our results not only implicate a biological role for AR expression and p16^Ink4a deletion in the pathogenesis of prostatic SRCC, but also provide a new and unique genetically engineered mouse (GEM) model for investigating the molecular mechanisms for SRCC development.

Primary Signet Ring Cell Carcinoma of the Prostate: A Rare Case Report

Primary prostatic signet ring cell carcinoma is a rare form of cancer with a poor prognosis, which is generally treated with a traditional prostate adenocarcinoma therapy. This case report presents a 70-year-old diagnosed with primary prostatic signet ring cell carcinoma, treated with a combination of radiotherapy and hormone therapy and a 16 month survival without an evidence of the disease at follow up.

Metastatic Gastric Signet Ring Cell Carcinoma Mimicking Crohn's Disease

Signet-ring cell carcinoma (SRCC) is an adenocarcinoma characterized by mucin-producing cells and most commonly arises in the stomach. Colonic SRCC can share features of colitis, including long segments of concentric bowel wall thickening and ulcerated mucosa with regions of sparing. We describe a rare case of metastatic gastric SRCC mimicking Crohn’s disease. Our patient underwent 2 colonoscopies, and biopsies revealed chronic active inflammation with no evidence of malignancy. The diagnosis of SRCC was only made after colectomy was performed for recurrent bowel obstruction.

Good response of an aggressive rare variant of signet ring cell carcinoma of prostate with hormonal therapy

Primary signet ring cell carcinoma (SRCC) of the prostate is a rare entity, characterised by its aggressive nature and dismal prognosis. We report a case of an advanced SRCC of the prostate presenting as a large pelvic mass with obstructive uropathy and rectal involvement managed by complete androgen blockade. At 24 months follow-up, the patient has no evidence of progression or metastasis. Aggressive management with multimodality approach combining surgery, radiation and hormonal ablation can result in long disease-free survival in some patients, despite the aggressive nature of this disease.

Focal Signet Ring Cell High-Grade Prostatic Intraepithelial Neoplasia on Needle Biopsy

Signet ring cell prostatic intraepithelial neoplasia is a rare speculated variant of high-grade prostatic intraepithelial neoplasia (HGPIN). Here, we present a free-standing and isolated signet ring cell HGPIN that was not associated with invasive carcinoma on needle biopsy and demonstrated the existence of this type of HGPIN variant. The differentiation between HGPIN and intraductal carcinoma of prostate is also discussed.

Primary signet ring cell carcinoma of the prostate treated by radical cystoprostatectomy and chemoradiotherapy

Primary signet ring cell carcinoma (SRCC) of the prostate is very rare. Although SRCC is primarily found in the stomach and colon, it can also be found in the pancreas, breast, thyroid, bladder, and prostate. We recently diagnosed and treated a case of primary SRCC of the prostate. A 56-year-old Korean man was referred to our institution for evaluation of a one-month history of hematuria and recently identified bladder mass. Transurethral resection of the bladder tumour was performed and histological and immunohistochemical evaluation revealed a diagnosis of SRCC with tumour invading into the outer half of the deep muscularis propria. After three weeks, the patient had radical cystoprostatectomy with ileal conduit. Tumour involved both prostate and bladder, but the centre of the tumour was located in the prostate. Duodenoscopy and colon fibroscopy both indicated no evidence of tumour origin in the gastrointestinal (GI) tract. Overall, this tumour was regarded as primary SRCC of the prostate. Concurrent chemoradiotherapy (CCRT) using leucovorin and fluorouracil was initiated two months later. The patient eventually developed bone and liver metastases and died of hepatopathy.

The pathology of unusual subtypes of prostate cancer

There are some current literatures describing the morphologic change of prostate carcinoma variants. Some subtypes do not respond to hormone deprivation therapy, for example adenosquamous and squamous cell carcinoma (SQCC), basaloid and adenoid cystic carcinoma (ACC), small cell carcinoma (SmCC), sarcomatoid carcinoma, urothelial carcinoma; some are defined in special Gleason grade, some develop different prognosis. So, it is very important to identify these rare subtypes to avoid misdiagnosis. In this review, we aim to describe the typical clinicopathological features of the rare variants of prostate cancer, including prostate acinar adenocarcinoma morphologic variants.

[Primary signet ring cell carcinoma of the prostate: a rare tumor]

The prostate is a very rare localization of signet ring cell carcinoma, with few cases reported in the literature. This histological type occurs rather in cancers of the digestive tract (stomach, colon). Authors report a case of a patient aged 63 years. Diagnostic and therapeutic features are discussed.

Primary signet ring cell carcinoma of the prostate

A 61-year-old Korean man was referred to our institution because of high prostate-specific antigen (PSA) (8.1ng/mL) and frequency, nocturia that had lasted for the previous 4 months. The first transrectal ultrasonography (TRUS)-guided prostate biopsy result was benign prostatic hyperplasia. About 3 years later, the patients revisited our institute for elevated PSA (14.7 ng/mL) and back pain. The patient underwent a second TRUS-guided prostate biopsy. Histological examination and immunohistochemical staining showed a signet ring cell carcinoma (SRCC). Also there were multiple bony metastasis. Androgen deprivation therapy (ADT) was started. Nine months later, the patient was diagnosed with hormone refractory prostate cancer and the ADT was changed into docetaxel chemotherapy. The patient died after 2 cycles of chemotherapy. We report this case of a SRCC of the prostate and review the literature.

Mesothelioma with signet-ring cell features: report of 23 cases

Signet-ring cell mesothelioma is uncommon and only two case reports have been published on this mesothelioma variant, both of which were initially misdiagnosed as signet-ring cell carcinoma. Herein are reported 23 signet-ring cell mesotheliomas that were investigated by immunohistochemistry, 12 of which were also studied by electron microscopy. Twenty-one of the cases originated in the pleura and two in the peritoneum. For comparison purposes and in order to determine the value of these techniques in the differential diagnosis of these tumors, seven cases of signet-ring cell lung adenocarcinoma were also studied. All signet-ring cell mesotheliomas were positive for calretinin, keratin 5/6, keratin 7, and mesothelin, 93% for podoplanin, and 91% for WT1; whereas, none reacted for MOC-31, CEA, TAG-72, CD15, TTF-1, napsin A, or CDX2. Among signet-ring cell lung adenocarcinomas, 100% were positive for keratin 7, CEA, and napsin A, 86% each for TTF-1 and TAG-72, 71% for CD15, and 14% for mesothelin, while all were negative for calretinin, keratin 5/6, WT1, podoplanin, and CDX2. After analyzing the results, it is concluded that the panels of markers used in the differential diagnosis of this mesothelioma variant should include those markers that are usually expressed in mesotheliomas (eg, calretinin, keratin 5/6, WT1, and podoplanin), broad-spectrum carcinoma markers that are frequently expressed in adenocarcinomas regardless of their site of origin (eg, MOC-31 and CEA), and organ-associated markers (eg, TTF-1 and napsin A for lung), which allow the site of origin of a metastatic adenocarcinoma to be established. Electron microscopy can be very useful as it permits the identification of characteristic ultrastructural mesothelioma and adenocarcinoma markers, and it also allows a better understanding of the morphologic features seen on routine light microscopy. Pathologists should be aware of this mesothelioma subtype as it can potentially be confused with other tumors that exhibit signet-ring features.

Anti-glutamate receptor 2 as a new potential diagnostic probe for prostatic adenocarcinoma: a pilot immunohistochemical study

Diagnoses of prostatic carcinoma (PC) have increased with widespread screening. While the use of α-methylacyl coA racemase and high molecular weight cytokeratins have aided in distinguishing benign mimics from malignancy, their sensitivity and specificity are limited. We studied 6C4, a monoclonal antibody to glutamate receptor 2, an excitatory amino acid receptor subunit distributed throughout the central nervous system, on benign prostatic epithelium, high-grade prostatic intraepithelial neoplasia, and PC. Ten cases with post-atrophic or adenosis-like prostate glands were also stained with prostatic intraepithelial neoplasia 4, an immunostain cocktail against α-methylacyl coA racemase, p63, and high molecular weight cytokeratin, in parallel with 6C4. Immunoreactivity for 6C4 was graded as negative (0% to 10%), +1 (11%% to 50%), and +2 (>50%). Malignant epithelium was classified by Gleason patterns. Gleason patterns 4 and 5 were subdivided into cribriform or noncribriform type. Its utility in distinguishing postatrophic or adenosis-like glands from prostate cancer, both of which show absence of basal cells on prostatic intraepithelial neoplasia 4 immunostain, was also investigated. Our results revealed a statistically significant difference in staining of benign secretory prostatic epithelium, high-grade prostatic intraepithelial neoplasia, and low Gleason pattern carcinomas. The results also showed 6C4 is a sensitive marker in separating basal cell negative postatrophic or adenosis-like glands from prostate carcinoma. In addition, there was a statistically significant difference between staining of cribriform versus noncribriform Gleason pattern 4 and 5 carcinomas. A limited number of lymph node metastases from cribriform and noncribriform carcinomas were studied, and they stained the same as the primary tumor in the majority of cases. In conclusion, our preliminary data demonstrated potential utility of 6C4 in the pathologic evaluation of PC.

Signet-ring-cell carcinoma of stomach metastatic to the bladder: a case report with cytological and histological correlation and literature review

BACKGROUND

Bladder involvement by a secondary tumor is fairly rare and an uncommon source of bladder metastasis is the stomach.

CASE REPORT

The authors report a case of a 38-year-old man with a bladder metastasis from a gastric signet-ring-cell (SRC) adenocarcinoma who presented with ematuria. The clinical history and the presence of SRCs in the voided urinary cytology and histologically in the suburothelial connective, with an overlying intact urothelium suggested a diagnosis of bladder metastasis from gastric carcinoma.

CONCLUSION

Bladder involvement by a secondary tumor is very rare, and a SRC carcinoma metastatic to the bladder, albeit extremely rare, should be considered in the differential diagnosis.

Younger age is an independent predictor for poor survival in patients with signet ring prostate carcinoma

Objective. The aim of this study was to examine the epidemiology, natural history, treatment pattern, and predictors of long-term survival of signet ring prostate carcinoma (SRPC) patients based on the analysis of the national Surveillance, Epidemiology, and End Results (SEER) database. Methods & Results. Between 1980 and 2004, a total of 93 patients with pathologically confirmed SRPC were identified. The mean age was 70 ± 11 years old. 82.8% of the patients had poorly or undifferentiated histology grade. 13.9% patients presented with metastatic disease. The 1-, 3-, and 5-year cancer-specific survival rates were 94.6%, 89.6%, and 83.8%, respectively. Using multivariate Cox proportional hazard model, younger age (40-50 versus age >70 yrs, P = .01), advanced tumor stage (distant versus local/regional, P = .02), and earlier diagnosis year (before 1995 versus after 1995, P = .01) were predictors of worse cancer specific survival. Conclusions. Despite more aggressive cancer therapy, younger SRPC patients had a worse cancer specific survival. This information could be useful when counseling these patients and emphasizes the need for new strategies and molecular-based therapeutic approaches for younger patients with SRPC.

Primary signet ring cell carcinoma of the prostate

Nine patients treated with primary signet ring cell carcinoma of the prostate were identified among 29,783 cases of prostate cancer evaluated at Mayo Clinic from January 15, 1970, until January 2, 2009. A PubMed search of the English-language literature published from January 1, 1980, to January 1, 2010, was then performed using the key words signet ring cell and prostate, identifying 42 cases. This study reviews those cases, along with the additional 9 reported herein, and evaluates clinical characteristics, histologic diagnoses, treatment modalities, and outcomes. Mean age at diagnosis was 68 years (range, 50-85 years), and mean prostate-specific antigen level was 95.3 ng/mL (range, 1.9-536.0 ng/mL; to convert to μg/L, multiply by 1). Most patients (66%) had non-stage IV carcinoma, the most common Gleason sum was 8 (33%), and mean survival was 29 months. The presence of a primary signet ring cell carcinoma of the prostate was best confirmed by negative findings on gastrointestinal work-up, a positive stain for prostate-specific acid phosphatase, and negative carcinoembryonic antigen test results.

A new case of signet ring cell carcinoma of the prostate

Primary signet ring cell carcinoma of the prostate is a very rare variant of prostate cancer. Herein, we report a new case of primary signet ring cell carcinoma of the prostate in an 85-year-old man with voiding disorder and hematuria. Based on this case, we present the anatomopathologic, clinical, and therapeutic aspects of this rare entity.

Primary signet-ring cell carcinoma mimicking segmental Crohn's colitis

Primary signet-ring cell carcinoma of the colon is a rare entity with a dismal prognosis, mainly due to a delay in diagnosis. Here, we present a case of a 30-year-old Filipino woman who presented with symptoms mimicking inflammatory bowel disease. A barium enema and colonoscopy demonstrated a stricture in the rectosigmoid region. A biopsy revealed granulomatous changes indicative of inflammatory bowel disease. Despite initial improvement of her symptoms on total parenteral nutrition and steroids, the patient relapsed several weeks later with recurrent left lower quadrant pain. A subsequent biopsy revealed poorly differentiated signet-ring cell carcinoma of the colon. She was treated surgically with a left hemi-colectomy and primary repair. A high degree of suspicion is necessary to correctly diagnose these, often young, patients with primary signet-ring cell carcinoma early and have a positive impact on survival. The literature on primary signet-ring cell carcinoma is reviewed.

Immunohistochemistry in diagnostic surgical pathology of the prostate

Immunohistochemistry (IHC) can play an important role in diagnostic surgical pathology of the prostate. Basal cell markers, such as the 34betaE12 antibody and antibodies directed against cytokeratin 5 and 6 or p63, are very useful for demonstration of basal cells as their presence argues against a diagnosis of invasive prostatic carcinoma (PC). However, several benign mimickers of PC, including atrophy, atypical adenomatous hyperplasia (AAH), nephrogenic adenoma, and mesonephric hyperplasia, can stain negatively with these markers, and thus, a negative basal cell marker immunostain alone does not exclude a diagnosis of benignancy. Although there are examples in the literature of high grade PC that stain focally with some of the basal cell markers, these cases are usually readily diagnosed based on H&E appearances and are unlikely to be confused with these benign mimickers. Alpha-methylacyl-coenzyme-A racemase (AMACR) is a sensitive marker of PC (except for a few uncommon variants: atrophic, foamy gland, and pseudohyperplastic variants), and its detection by immunohistochemical staining in atypical prostatic lesions can be very useful in confirming an impression of adenocarcinoma. AMACR expression can also be identified in high grade prostatic intraepithelial neoplasia (PIN), prostatic atrophy, AAH, and benign prostatic glands, and accordingly, a diagnosis of PC should not be based solely on a positive AMACR immunostain, especially when the luminal staining is weak and/or noncircumferential. The use of AMACR/basal cell antibody cocktails has been found to greatly facilitate the distinction between PC and its benign mimickers, especially when only limited tissue is available for staining. Prostate specific antigen (PSA) and prostate specific acid phosphatase (PSAP) are both quite sensitive and fairly specific markers of PC (there are a few nonprostatic tumors that can express one or both), and are both very helpful in establishing or confirming the diagnosis of PC when the differential diagnosis includes other tumors that can involve the prostate such as urinary bladder urothelial carcinoma. 34betaE12, p63, thrombomodulin, and uroplakin III are additional urothelial associated markers useful in this differential diagnosis. CDX2 and villin are useful markers to diagnostically separate colonic adenocarcinoma from PC. AMACR positivity and negative basal cell marker reactions are useful to confirm the presence of residual PC after hormonal or radiation therapy. Pan-cytokeratin, PSA, and PSAP can also highlight subtle infiltrates of PC with hormonal or radiation therapy effect. PSA and PSAP immunohistochemical stains are valuable in confirming metastatic carcinoma as being of prostatic origin and should always be utilized in the diagnostic evaluation of metastatic adenocarcinoma of unknown primary origin in males.