The endocrine component of prostatic carcinomas, mixed adenocarcinoma-carcinoid tumours and non-tumour prostate. Histochemical and ultrastructural identification of the endocrine cells

Development of Neuroendocrine Prostate Cancers by the Ser/Arg Repetitive Matrix 4-Mediated RNA Splicing Network

While the use of next-generation androgen receptor pathway inhibition (ARPI) therapy has significantly increased the survival of patients with metastatic prostate adenocarcinoma (AdPC), several groups have reported a treatment-resistant mechanism, whereby cancer cells can become androgen receptor (AR) indifferent and gain a neuroendocrine (NE)-like phenotype. This subtype of castration-resistant prostate cancer has been termed "treatment-induced castration-resistant neuroendocrine prostate cancer" (CRPC-NE). Recent reports indicate that the overall genomic landscapes of castration-resistant tumors with AdPC phenotypes and CRPC-NE are not significantly altered. However, CRPC-NE tumors have been found to contain a NE-specific pattern throughout their epigenome and splicing transcriptome, which are significantly modified. The molecular mechanisms by which CRPC-NE develops remain unclear, but several factors have been implicated in the progression of the disease. Recently, Ser/Arg repetitive matrix 4 (SRRM4), a neuronal-specific RNA splicing factor that is upregulated in CRPC-NE tumors, has been shown to establish a CRPC-NE-unique splicing transcriptome, to induce a NE-like morphology in AdPC cells, and, most importantly, to transform AdPC cells into CRPC-NE xenografts under ARPI. Moreover, the SRRM4-targeted splicing genes are highly enriched in various neuronal processes, suggesting their roles in facilitating a CRPC-NE program. This article will address the importance of SRRM4-mediated alternative RNA splicing in reprogramming translated proteins to facilitate NE differentiation, survival, and proliferation of cells to establish CRPC-NE tumors. In addition, we will discuss the potential roles of SRRM4 in conjunction with other known pathways and factors important for CRPC-NE development, such as the AR pathway, TP53 and RB1 genes, the FOXA family of proteins, and environmental factors. This study aims to explore the multifaceted functions of SRRM4 and SRRM4-mediated splicing in driving a CRPC-NE program as a coping mechanism for therapy resistance, as well as define future SRRM4-targeted therapeutic approaches for treating CRPC-NE or mitigating its development.

Primary well differentiated neuroendocrine tumor of the filum terminale. Case report and literature review

OBJECTIVE

To present a case of a well-differentiated primary intradural-extramedullary neuroendocrine tumor of the filum terminale and to conduct a literature review.

CASE

A 68-years old patient was assessed after presenting lower back pain and sciatica with ineffective pain relief. The patient presented an intradural-extramedullary lumbar lesion arising from the filum terminale, which was partially resected. The pathology diagnosis was a well-differentiated primary neuroendocrine tumor (carcinoid tumor). After a multidisciplinary evaluation, fractionated stereotactic radiotherapy was administered. No progression or metastatic spread was observed in successive assessments.

DISCUSSION

Neuroendocrine tumors are heterogeneous neoplasms derived predominantly from enterochromaffin cells, in which chemotherapy plays a very limited role. In contrast, radiotherapy has been described in partially resected lesions.

CONCLUSION

Well-differentiated primary neuroendocrine tumors with intradural-extramedullary lumbosacral location are an exceptional rarity. Isolated surgical resection, or associated with an adjuvant radiotherapy treatment in subtotal resections, could be considered an effective therapeutic strategy.

Utility of FDG-PET in clinical neuroendocrine prostate cancer

BACKGROUND

Fluorodeoxyglucose (FDG) positron emission tomography (PET) has well-characterized limitations in prostate adenocarcinoma (PCA). However, data assessing the utility of PET in neuroendocrine prostate cancer (NEPC) is limited to isolated case reports. Herein, we describe the first case series to assess the utility of FDG-PET in NEPC.

METHODS

Inclusion criteria consisted of clinically progressive metastatic PCA in the setting of a chromogranin-A levels >1.5× the upper limit of normal, and ≥1 FDG-PET scan after the diagnosis of NEPC, which yielded 23 patients. All metastatic lesions on CT, PET, and bone scan were read by two independent physicians.

RESULTS

Five hundred ninety two unique lesions were identified across all imaging modalities, 510 were bone metastases, and 82 were soft tissue metastases. Of bone lesions, 22.2%, 92.7%, and 77.6% were detected by PET, CT, and bone scan, respectively. Of soft tissue lesions, 95.1% and 97.5% were detected by PET and CT, respectively. Stratified by the median survival from NEPC diagnosis, patients who survived <2.2 versus ≥2.2 years had more PET avid bone (8 vs. 2, P = 0.06) and soft tissue lesions (7 vs. 1, P = 0.01), and higher average SUVmax of bone (5.49 vs. 3.40, P = 0.04) and soft tissue lesions (8.02 vs. 3.90, P = 0.0002).

CONCLUSIONS

In patients with clinical NEPC, we demonstrate that FDG-PET has clinical utility in the detection of metastatic disease. In addition to detection, PET allows for treatment response to determine tumor viability. With novel therapies on the horizon to treat NEPC, consideration to investigate the use of FDG-PET to monitor response is warranted.

Mixed pituitary adenoma/craniopharyngioma: clinical, morphological, immunohistochemical and ultrastructural study of a case, review of the literature, and pathogenetic and nosological considerations

Mixed pituitary adenoma/craniopharyngiomas are very rare tumors. Their pathogenesis is still unclear and it is not known whether they are collision tumors derived from independent stem cells or whether they originate from a single stem cell undergoing divergent differentiation. The latter hypothesis is supported by the close commixture between the two tumor components with transition areas that has been previously described. However, "hybrid" cells with both pituitary adenoma and craniopharyngioma features have never been described. In this paper we report a case of mixed pituitary adenoma/craniopharyngioma observed in a 75-year-old woman presenting with diplopia and slight increase of serum prolactin, who underwent endoscopic endonasal trans-sphenoidal tumor resection. Histologically, the tumor was composed of a typical pituitary silent subtype 2 ACTH cell adenoma admixed with islands of adamantinomatous craniopharyngioma. Electron microscopy showed that, in addition to distinct silent subtype 2 ACTH and craniopharyngioma cells, there were "hybrid" cells, showing characteristics of both pituitary adenoma and craniopharyngioma, consisting of small dense secretory granules, bundles of cytoplasmic filaments, and desmosomes. This ultrastructural finding was also confirmed by the presence of cells showing nuclear p40 expression and chromogranin A immunoreactivity. The close commixture between the two components and the ultrastructural and immunohistochemical findings demonstrate a common histogenesis of the two components and support the classification of the neoplasm as a mixed tumor. The patient completely recovered and, 10 months after surgery, head MR confirmed the complete resection of the lesion.

Hepsin cooperates with MYC in the progression of adenocarcinoma in a prostate cancer mouse model

BACKGROUND

Hepsin is a cell surface protease that is over-expressed in more than 90% of human prostate cancer cases. The previously developed Probasin-hepsin/Large Probasin-T antigen (PB-hepsin/LPB-Tag) bigenic mouse model of prostate cancer demonstrates that hepsin promotes primary tumors that are a mixture of adenocarcinoma and neuroendocrine (NE) lesions, and metastases that are NE in nature. However, since the majority of human prostate tumors are adenocarcinomas, the contribution of hepsin in the progression of adenocarcinoma requires further investigation.

METHODS

We crossed the PB-hepsin mice with PB-Hi-myc transgenic mouse model of prostate adenocarcinoma and characterized the tumor progression in the resulting PB-hepsin/PB-Hi-myc bigenic mice.

RESULTS

We report that PB-hepsin/PB-Hi-myc bigenic mice develop invasive adenocarcinoma at 4.5 months. Further, histological analysis of the 12- to 17-month-old mice revealed that the PB-hepsin/PB-Hi-myc model develops a higher grade adenocarcinoma compared with age-matched tumors expressing only PB-Hi-myc. Consistent with targeting hepsin to the prostate, the PB-hepsin/PB-Hi-myc tumors showed higher hepsin expression as compared to the age-matched myc tumors. Furthermore, endogenous expression of hepsin increased in the PB-Hi-myc mice as the tumors progressed.

CONCLUSIONS

Although we did not detect any metastases from the prostates in either the PB-hepsin/PB-Hi-myc or the PB-Hi-myc mice, our data suggests that hepsin and myc cooperate during the progression to high-grade prostatic adenocarcinoma.

Delirium with severe symptom expression related to hypercalcemia in a patient with advanced cancer: an interdisciplinary approach to treatment

Delirium is considered to be multifactorial, especially in elderly patients and those with advanced cancer, and can cause significant distress. High baseline vulnerability at the end of life, combined with cachexia, hepatic impairment, general comorbidities, and impaired functional status, can make delirium difficult to correct. Nonetheless, approximately 50% of delirium episodes are potentially reversible and reversible causes should be investigated. Hypercalcemia is one of the reversible metabolic causes of delirium in patients with advanced cancer. Here, we present the case of a patient with metastatic small cell prostate carcinoma who presented to our palliative care clinic with uncontrolled symptoms. A thorough evaluation using appropriate assessment tools revealed that he had delirium, and hypercalcemia was found to be the major etiologic factor. An interdisciplinary team approach (including a nutritionist, pharmacist, counselor, social worker, chaplain, and case manager) was provided. With aggressive symptom management and correction of hypercalcemia and other reversible causes of delirium, the delirium was resolved and the symptoms were controlled. This case illustrates the importance of screening for delirium in patients with severe symptom distress and how the interdisciplinary management of reversible causes of delirium, including hypercalcemia, can improve patients' symptoms and quality of life.

Cushing syndrome associated with prostatic tumor adrenocorticotropic hormone (ACTH) expression after maximal androgen blockade therapy

We report a patient with adenocarcinoma of the prostate, who eventually developed Cushing syndrome due to ectopic adrenocorticotropic hormone (ACTH) secretion from the tumor. At first, maximal androgen blockade (MAB) therapy was effective for the prostate carcinoma, which was positive for prostate-specific antigen (PSA) and negative for ACTH on the biopsy specimen. However, 3 years later, the patient complained of bilateral leg edema. A chest computed tomographic (CT) scan showed bilateral pleural effusion and inflammatory changes, focused on the right upper-lobe. While his PSA was not elevated, and there were no obvious tumor metastases, his serum cortisol and ACTH levels were elevated, without any evidence of lesions that could release ectopic ACTH. Two weeks later, the patient complained of dyspnea and bilateral pleural effusion, and inflammatory changes were worse. Although the patient was administered inhibitors of adrenocorticoid synthesis-metyrapone, they did not have enough clinical efficiency. Steroid pulse therapy was also administered but the patient's severe pneumonia and pleural effusion did not improve and he finally died of respiratory failure. In contrast to the initial biopsy specimen findings, on autopsy, the tumor was negative for PSA but positive for ACTH. Thus, it would appear that the tumor began to produce and release ectopic ACTH after therapy, which resulted in the development of Cushing syndrome in this patient with prostate carcinoma.

Tissue evidence of the testosterone role on the abnormal growth and aging effects reversion in the gerbil (Meriones unguiculatus) prostate

Prostate differentiation during embryogenesis and its further homeostatic state maintenance during adult life depend on androgens. Abundant biological data suggest that androgens play an important role in the development of the prostate cancer and other prostatic diseases. The objective of this work was to evaluate the effects of the testosterone supplementation in gerbil (a new experimental model) at different ages. Tissues from experimental animals were studied by histological and histochemistry procedures, androgen receptor immunohistochemistry assay, morphometric-stereological analysis, and transmission electron microscopy (TEM). After the treatment were observed increase of prostate weight and epithelium height in all ages studied. In some adult and aged treated animals, hyperplasic and dysplastic process were observed, including prostatic intraepithelial neoplasias and adenocarcinomas. Increase of the thickness of the smooth muscle cell (SMC) layer was observed in pubescent and adult animals and TEM revealed apparent SMC hypertrophy. An apparent increase in the frequency of blood vessels distributed by the subepithelial stroma in the treated animals was noticed. Reversion of the natural effects of aging on the prostate was observed in the aged treated animals in some acini of the gland. These data demonstrate that the gerbil prostate is susceptible to androgenic action at the studied ages and it can serve, for example, as experimental model to studies of prostate neoplastic process induction and hormonal therapy in aged animals.

Carcinoid tumors of the urinary tract and prostate

CONTEXT

Carcinoid tumors are exceedingly rare in the genitourinary tract and may occur in the kidney, urinary bladder, urethra, or prostate.

OBJECTIVE

To review the clinical and pathologic features of carcinoid tumors occurring in the urinary tract and prostate.

DATA SOURCES

We searched the English language literature using MEDLINE and Ovid.

CONCLUSIONS

Carcinoid tumors of the urinary tract and prostate share similar morphologic features with their counterparts in other organs. The differential diagnosis includes metastatic carcinoid tumor, paraganglioma, and nested variants of urothelial and prostatic carcinomas. Correlation of the clinical presentation and histopathologic features (including the immunohistochemical profile) will ensure accurate diagnosis of these rare tumors.

Low-grade neuroendocrine carcinoma (carcinoid tumor) of the prostate

A case of primary, prostatic, low-grade neuroendocrine carcinoma (carcinoid tumor) is described. The patient is an 86-year-old man who presented with symptoms of gross hematuria of several days' duration. Physical examination and a bladder biopsy specimen revealed the presence of a primary adenocarcinoma of the bladder with invasion into the muscularis propria. A cystoprostatectomy was performed, which revealed the presence of invasive adenocarcinoma of the bladder. Prostatic sampling demonstrated the presence of a low-grade neuroendocrine carcinoma (carcinoid tumor) and a small focus of well-differentiated conventional adenocarcinoma. Immunohistochemical studies using neuroendocrine markers clearly demarcated the presence of the neuroendocrine tumor. The case presented herein highlights the ubiquitous distribution of neuroendocrine neoplasms along the male genitourinary tract and the presence of 3 separate neoplasms in the genitourinary tract.

Relationship between neuroendocrine features and prognostic parameters in human prostate adenocarcinoma

PURPOSE

The biological behaviour of prostate cancer is highly variable and prediction by the commonly employed prognostic parameters is not sufficient. The concept of neuroendocrine (NE) differentiation in prostate adenocarcinoma has recently received increasing attention due to possible implications for prognosis and therapy.

MATERIALS AND METHODS

Core needle biopsies from 142 newly diagnosed patients were immunohistochemically examined for the coexistence of NE differentiation using an antibody against chromogranin A (CgA). Circulating CgA was available in 106 of these patients.

RESULTS

NE differentiation was found in 64 (45.1%) tumors. Among them 29 (20.4%) had CgA positive cells scattered or focally distributed in less than 5% per mm3 of tumor tissues, 26 (18.3%) between 5% and 10% and 9 (6.4%) more than 10%, respectively. There was a significant correlation between the extent of NE features and either Gleason score (P < 0.01) or stage of disease. Circulating CgA but not PSA correlated with immunohistochemical CgA (P < 0.03) particularly in metastatic cases.

CONCLUSIONS

These data support the concept that NE differentiation in human prostate cancer has a negative prognostic significance. Circulating CgA levels reflect immunohistochemical findings.

Chromogranin a concentration as a serum marker to predict prognosis after endocrine therapy for prostate cancer

PURPOSE

Chromogranin A is gaining acceptance as a serum marker of neuroendocrine tumors and the concentration is thought to be elevated in relation to neuroendocrine differentiation of prostate cancer. We examined the significance of the chromogranin A level as a serum marker for prostate cancer.

MATERIALS AND METHODS

Serum chromogranin A values were determined by monoclonal immunoradiometric assay in 108 patients with prostate cancer before treatment and in 66 with benign prostatic hyperplasia. In those with prostate cancer clinicopathological parameters, the response to endocrine therapy and the prognosis were evaluated in relation to serum chromogranin A.

RESULTS

Mean serum chromogranin A plus or minus standard deviation in prostate cancer and benign prostatic hyperplasia cases was 59.4 +/- 52.5 and 59.3 +/- 44.3 ng./ml., respectively (not significant). Poorly differentiated adenocarcinoma was associated with higher chromogranin A than well differentiated disease (p = 0.044). Of the stage D cases with a median prostate specific antigen (PSA) of 172.1 ng./ml. or less those with higher chromogranin A had a poorer prognosis than those with lower chromogranin A. In contrast, in stage D cases with a PSA of greater than 172.1 ng./ml. there was no difference in the prognosis between the higher and lower chromogranin A groups.

CONCLUSIONS

Serum chromogranin A tends to be elevated in patients with high grade prostate cancer. When combined with PSA, this marker may effectively predict a poor prognosis after endocrine therapy.

Serologic tumor markers, clinical biology, and therapy of prostatic carcinoma

PSA has been a valuable tool in enhancing our understanding of the prevalence and virulence of prostate cancer. PSA also has contributed to the understanding of important phenomena related to the androgen regulation of the cancer; however, it has not been useful in detecting some forms of androgen-independent (neuroendocrine) progression and is of limited prognostic value in androgen-independent prostate cancer. PSA also has been valuable in the accelerated development of therapies for prostate cancer; however, it must be used cautiously for this purpose, because it may not reflect the most relevant clone. In addition, some agents may directly affect PSA release independent of their antitumor activity. Most importantly, before PSA is adopted as a surrogate end point in clinical trials in prostate cancer, it must be prospectively validated. Future studies must focus on the development of prospective serologic tumor markers that can predict virulence of disease and to reflect androgen-independent progression.

Immunohistochemical distribution of rabbit polyclonal antiurinary protein 1 antibody in the female (Skene's gland) and male prostate: new marker for neuroendocrine cells?

Using rabbit polyclonal antiurinary protein 1 antibody to study the female prostate (Skene's gland) and the male prostate, characteristic localizations patterns appeared in single cells and groups of cells. The majority correspond to cells positive for neuroendocrine markers. In the cytoplasm, cells positive for protein 1 were most frequently found in the epithelial lining of the female urethra, in the pars prostatica of the male urethra, and in the ducts of the female and male prostate where the lining consisted of pseudostratified columnar epithelium. Their occurrence rate was far lower among secretory and basal cells of the male and female prostate glands. The cells with protein 1 corresponded to those displaying positivity for chromogranin A, silver staining by the Grimelius and less by the Sevier-Munger method, and by neuron specific enolase. Using the Masson-Hamperl argentaffin method, positive cells were only exceptionally found. The cells positive for protein 1, and particularly chromogranin A, and characterized by Grimelius positivity, contained different amounts of neuroendocrine granules and varied in size and shape. The majority of these cells had contact with the lumen of male and female prostatic ducts (open type of neuroendocrine cells). In some cases of the male and female urethra and of the great paraurethral ducts, a remarkably high number of cells containing protein 1 corresponded to cells only containing neuron-specific enolase but not chromogranin A and other neuroendocrine markers. These cells can be considered stem cells responsible for the renewal of the uroepithelium of the urethra and prostatic ducts. Protein 1 may thus be a further, though presumably not specific marker for the identification of cells of the neuroendocrine system in the prostate of the male and female. This marker could well be used to study uroepithelium maturation. The corresponding immunohistochemical distribution of human protein 1 in neuroendocrine and other cells of the male and the female prostate provides another analogous functional and morphological parameter of prostatic tissue in both sexes and further evidence supporting the non-vestigial concept of the prostate in the female.

Neuroendocrine differentiation in prostate cancer: enhanced prediction of progression after radical prostatectomy

It is controversial whether neuroendocrine (NE) differentiation in adenocarcinoma of the prostate is associated with more aggressive behavior. Most studies included patients with tumors of a wide range of grades and stages and an end point of disease-specific survival, a relatively insensitive marker of progression. The authors studied completely embedded radical prostatectomy specimens from 104 patients with clinically organ-confined carcinoma and no history of adjuvant or neoadjuvant therapy. Progression was marked by a serum prostate-specific antigen (PSA) concentration greater than or equal to 0.2 ng/mL. Seventy-six men did not progress, with a mean follow-up period of 8.0 years (range = 7 to 10 years). Forty-eight men progressed at a mean time after surgery of 3.6 years (range = 1 to 8 years). Twenty-one percent of the tumors were organ confined: 79% had capsular penetration. Seminal vesicles and lymph nodes were negative in all cases. A representative section through the main tumor mass was stained for chromogranin A. Reactive neoplastic cells were counted subjectively as well as individually enumerated. Gleason grade, pathological stage, and degree of NE differentiation all correlated with progression. Only grade and extent of NE differentiation predicted progression in a multivariate analysis. NE differentiation did not correlate with stage or grade. Extent of NE differentiation separated patients (59 cases) with tumors of Gleason sum less than or equal to 6 into groups with high and low risks for progression (P < .008) independent of Gleason sum. Extent of NE differentiation provides prognostic information in addition to that provided by grade in cases of early prostate cancer treated by radical prostatectomy.

Neuroendocrine differentiation in metastatic prostatic adenocarcinoma

Neuroendocrine differentiation of prostatic adenocarcinoma has received considerable attention in recent years. The objectives of this study were to characterize the incidence, pattern of distribution and peptide hormone immunoreactivities of neuroendocrine differentiated tumor cells in prostatic carcinoma metastases; determine the correlation of neuroendocrine differentiation and deoxyribonucleic acid content in lymph node metastases, and determine the prognostic role of neuroendocrine differentiation of metastases in stage D1 cancer. We examined immunohistochemically 62 metastatic lesions (41 pelvic lymph nodes and 21 bone metastases) for the presence of chromogranin-A expressing tumor cells. Of 41 lymph nodes and 21 bone metastases 19 (46%) and 11 (52%), respectively, contained chromogranin-A immunoreactive cells. These cells were commonly found to comprise the minority of tumor cells in the metastases and typically were distributed in a dispersed pattern. Serotonin and peptide hormone immunocytochemistry in 19 cases (12 lymph nodes and 7 bone metastases) demonstrated neuroendocrine cells containing thyroid-stimulating hormone and serotonin in 17 (89%) and 10 (53%), respectively. All 7 bone metastases contained thyroid-stimulating hormone immunoreactive cells. The presence of chromogranin-A positive cells did not correlate statistically with deoxyribonucleic acid content of lymph node metastases nor with disease specific survival in patients with stage D1 prostate cancer. Our results indicate that a substantial proportion of prostate cancer metastases contain a subpopulation of cells expressing a neuroendocrine phenotype similar to primary tumors. These cells are capable of elaborating certain biogenic amines and peptide hormones. However, in stage D1 prostate cancer nodal lesions expressing neuroendocrine differentiation do not appear to have significant prognostic value.

Paneth cell-like change in prostatic adenocarcinoma represents neuroendocrine differentiation: report of 30 cases

Paneth cell-like change (PCLC) of the prostatic epithelium is considered to be a distinct form of neuroendocrine differentiation characterized by isolated cells or small groups of cells with prominent eosinophilic cytoplasmic granules. We evaluated 300 serially sectioned radical prostatectomy specimens from patients with prostatic adenocarcinoma who had not received prior adjuvant therapy (pathologic stages T2NOMO [177 patients], T3NOMO [100 patients], and TxN1MO [23 patients]). Paneth cell-like change was identified in 30 cases (10%), ranging from 1 to 20 high-power fields/positive case (mean, 4.1 high-power fields/case). There was no correlation of PCLC with prostate volume, prostate weight, Gleason grade, nuclear grade, lymph node metastases, serum prostate-specific antigen levels, cancer volume, area or presence of capsular perforation, seminal vesicle invasion, or glandular mucin (all P > .05), although a positive correlation was seen with cribriform pattern (r = 0.50, P = .0015). Immunohistochemistry revealed cytoplasmic immunoreactivity within cells of PCLC for chromogranin (seven of seven cases), neuron-specific enolase (seven of seven cases), serotonin (six of seven cases), prostate-specific antigen (five of seven cases), and prostatic acid phosphatase (four of seven cases); lysozyme was negative (seven cases). Our findings indicate that PCLC is more common than previously reported, but that it is not associated with tumor grade, serum PSA levels, or pathologic stage. This study also shows that PCLC represents neuroendocrine differentiation, suggesting that the term "Paneth cell-like change" be deleted from the pathologist's lexicon in relation to prostatic adenocarcinoma; a more appropriate term might be "neuroendocrine cells with large eosinophilic granules."

CCK-containing paraneurons in human adenomatous prostate

The presence of CCK-containing neuroendocrine cells in human adenomatous prostates, and the colocalization of CCK together with serotonin in the same cell, have been demonstrated by means of an immunohistochemical technique and by a double labeling immunofluorescent staining. CCK-containing neuroendocrine cells had a focal distribution in the prostates and sometimes showed dendrite-like cytoplasmic processes. The major part of CCK (96.55%) colocalized with serotonin. CCK probably stimulates muscle contraction and endocrine/exocrine secretions in the urogenital tract.

Reproduction and the APUD system

Substantial evidence for involvement of the APUD system in the normal reproductive tract is limited to the prostate gland and uterine cervix. Most supportive data simply documents the presence of neuro-endocrine cells in these tissues. A biological product(s) or role(s) remains to be discovered, but appears likely in the prostate. Tumors possessing cells with APUD characteristics have been described in many reproductive tissues including the prostate, cervix, endometrium, ovary, and testes. These tumors are generally aggressive in behavior, and optimum therapy needs to be determined.

The neuroendocrine cell population of the human prostate gland

Neuroendocrine cells have been reported in up to 50% of all prostatic adenocarcinomas. These cells appear to influence the prognosis of these tumors. The distribution of the neuroendocrine cell population in the normal prostate gland, through all stages of development, has not been documented previously. We define the distribution of this cell population and describe 4 cellular morphological variants. The neuroendocrine cells of the peripheral zone appear to respond to factors present at birth and at puberty, while those of the periurethral glands and prostatic duct system are not influenced by this factor. It is postulated that this factor may be the levels of circulating androgens. The presence of at least 2 functionally distinct populations of neuroendocrine cells raises the possibility of 2 different embryonic origins. The study documents the distribution of calcitonin-producing cells but fails to detect the presence of somatostatin.

Characterization of neuroendocrine differentiation in human benign prostate and prostatic adenocarcinoma

BACKGROUND

This report describes an immunohistopathologic analysis characterizing the incidence, pattern of distribution, and hormonal content of neuroendocrine (NE) cells in human benign prostate and prostatic adenocarcinoma.

METHODS

Formaldehyde-fixed, paraffin-embedded material from 15 benign prostates, 31 primary prostatic adenocarcinomas, 16 metastatic lesions, 21 primary tumors treated with short-course diethylstilbestrol (DES), and 10 specimens from hormone-refractory patients were examined. NE cells were identified using silver histochemistry and a panel of immunohistochemical NE markers (chromogranin-A, serotonin, neuron-specific enolase), and specific peptide hormone antibodies.

RESULTS

NE cells were identified in all benign prostates. NE cells were identified in 77% of primary untreated adenocarcinomas with no significant differences with respect to pathologic stage. NE cells were found isolated and dispersed in the tumor, composing the minority of malignant cells. Double-labeling and serial section immunohistochemistry demonstrated the coexpression of prostate-specific antigen (PSA) in NE cells. In addition to serotonin, some tumors expressed multiple hormone immunoreactivities. NE cells were identified in 56% of metastatic deposits, with a similar pattern of distribution. In DES-treated cases, NE cells were found consistently in the adjacent benign epithelium, whereas 52% of tumors contained NE cells. Hormone-refractory tumors contained NE cells in 60% of cases.

CONCLUSIONS

This analysis demonstrates that a significant proportion of primary and metastatic prostatic adenocarcinomas contain a subpopulation of NE cells, the expression of which does not appear to be suppressed with androgen ablation and does not correlate with pathologic stage. Furthermore, NE cells coexpress PSA, suggesting a common precursor cell of origin. The elaboration of biogenic amines and neuropeptides suggests that NE cells dispersed in prostatic carcinoma may play a paracrine growth-regulatory role.

Composite enteric-type adenocarcinoma-carcinoid of the nasal mucosa

The authors describe a patient whose nasal neoplasm demonstrated histological characteristics of both a moderately differentiated intestinal-type adenocarcinoma and an atypical carcinoid (well-differentiated neuroendocrine carcinoma). The adenocarcinoma displayed a predominantly papillary architecture, immunohistochemically positive staining for intestinal markers, and ultrastructural features (microvilli with long roots) characteristic of intestinal differentiation. The carcinoid component was argyrophilic, was immunoreactive with chromogranin, gastrin, and serotonin, and displayed ultrastructurally characteristic G and EC cells. The neoplasm recurred twice, and the tumor tissue from the second recurrence was composed only of neuroendocrine cells, indicating that this component was more resistant to the therapy (surgery and radiotherapy) employed. The patient died from an intracranial recurrence 5 months after the last combined surgical and radiotherapic treatment. Because of its unfavorable prognosis, a neuroendocrine-exocrine tumor should not be grouped with typical carcinoids or with well-differentiated papillary sinonasal adenocarcinomas, which seem to be less aggressive.

Neuroendocrine differentiation in carcinoma of the prostate. Diagnostic, prognostic, and therapeutic implications

Endocrine-paracrine cells of the prostate (also known as APUD or neuroendocrine cells) constitute, in addition to the basal and exocrine secretory cells, a third population of highly specialized epithelial cells in the prostate gland. These endocrine-paracrine cells contain, and most likely secrete, serotonin and calcitonin, as well as variety of other peptides. Little is known of the functional role of these cells, but they probably subserve a paracrine or local regulatory role. They may also regulate via endocrine, lumencrine, or neurocrine mechanisms. These endocrine-paracrine cells probably play a significant role during prostatic growth and differentiation as well as regulating the secretory process of the mature gland. Neuroendocrine differentiation in prostatic carcinoma occurs in the form of the relatively rare small cell carcinoma and carcinoid or carcinoid-like tumor, but most commonly as focal neuroendocrine differentiation in a conventional prostatic adenocarcinoma that is a very frequent, if not ubiquitous phenomenon, and reflects tumor cell heterogeneity mimicking the normal differentiation process. The world's literature on neuroendocrine differentiation in prostatic carcinoma is reviewed. Neuroendocrine differentiation in all types of prostatic carcinoma appears to correlate with a poor prognosis. This correlation is probably multifactorial and may relate to a positive correlation with grade, a direct resistance to hormonal manipulation, and/or autocrine/paracrine growth factor activity due to the secretion of neuroendocrine products. Neuron-specific enolase and chromogranin, as well as other neuroendocrine products, may be useful as serum markers in patients with prostatic carcinoma with neuroendocrine differentiation. New therapeutic strategies need to be developed to treat these tumors. This includes the use of specialized protocols that have been effective against neuroendocrine carcinomas arising in other organ systems.

Small cell carcinoma of prostate: effectiveness of hormonal versus chemotherapy

Small cell carcinoma of the prostate is rare and associated with a rapidly fatal course. Since 1977, 47 cases have been reported in the world literature with data from 3 additional cases presented herein. The purpose of our review was to determine the effectiveness of hormonal versus chemotherapy. Thirty-four of the 50 cases have known clinical histories. Four patients were not treated, and all were dead of their disease within an average of 2.75 months. Six patients were eliminated from our review because small cell carcinoma was discovered at autopsy. Another 5 cases were omitted because hormonal +/- chemotherapy had already been given for a previous diagnosis of adenocarcinoma, but no specific therapy was given once the small cell carcinoma developed. Of the remaining 19 cases, only 2 have survived. One is still alive forty-three months after hormonal treatment, and another is alive with disease six months after the initiation of hormonal therapy and chemotherapy. Five patients were given hormonal therapy only, and none of them responded. In 4 patients chemotherapy was given after hormonal therapy had failed, and they too died of their disease within a short period of time. However, an additional 8 patients were treated with immediate chemotherapy +/- hormonal therapy and had substantially longer clinical remissions. Therefore, although small cell carcinoma is a uniformly fatal disease, immediate chemotherapy should be considered to promote better clinical remissions.

Neuroendocrine differentiation in human prostatic carcinoma

Endocrine-paracrine (APUD, neuroendocrine) cells are located in the prostatic ductal and acinar epithelium. These cells are of the open and closed type and have dendritic processes. There is a wide range of secretory granule morphology presumably indicating a variety of different cell "types." Secretory immunoreactive peptides include serotonin, calcitonin (and related peptides), somatostatin, bombesin-like, thyroid-stimulating hormone-like (beta chain), and alpha-glycoprotein chain-like. These cells may function by endocrine, paracrine, neurocrine, and lumencrine mechanisms and play an important regulatory role both during growth and differentiation of the prostate as well as in the secretory process of the mature gland. Neuroendocrine differentiation in prostatic carcinoma is a frequent occurrence and manifests itself in several forms, including (1) small cell carcinoma, (2) carcinoid and carcinoid-like tumors, and (3) conventional adenocarcinoma with focal neuroendocrine differentiation. This latter pattern is the most common, and there is evidence that all or nearly all prostatic adenocarcinomas show at least some focal neuroendocrine differentiation. A review of the world's literature on this topic is included. Neuroendocrine differentiation generally portends a poorer prognosis but may also correlate directly with the grade. There is some evidence to suggest that neoplastic cells with neuroendocrine differentiation are resistant to hormonal therapy. Eutopic and ectopic hormone production may allow screening for prostatic carcinoma and/or monitoring for recurrence of prostatic carcinomas. Finally, the more basic implications of endocrine-paracrine cells and neuroendocrine differentiation are speculated on in reference to prostatic carcinogenesis and autocrine/paracrine tumor growth factor activity.

Elevated plasma chromogranin-A concentrations in prostatic carcinoma

Chromogranin-A is considered a sensitive immunohistochemical tissue marker in neuroendocrine prostatic carcinoma. We report that the plasma chromogranin-A level was elevated in 48% of 25 patients with stage D2 prostate cancer, and suggest that this marker can be used to monitor the clinical course of these patients.

Paraganglioma of urethra

Paraganglioma of the urethra is a rare tumor; only 4 cases have been reported previously. We report a fifth case of urethral paraganglioma and review the literature.

Production of calcitonin gene related peptide, calcitonin and PTH-related protein by a prostatic adenocarcinoma

PTH and calcitonin are the two major hormones controlling calcium metabolism. Recently two new substances related to these hormones have been isolated: calcitonin gene related peptide (CGRP) and PTH-related protein (PTHrP). CGRP is a potent vasodilator and stimulant of intestinal secretion while PTHrP is probably the agent responsible for humoral hypercalcaemia of malignancy. We report here a patient with a prostatic tumour presenting with vasodilation, diarrhoea and hypercalcaemia. Our investigations revealed that the primary prostatic and liver secondary tumour contained CGRP, calcitonin and PTHrP. Most of the immunoreactive CGRP in the tumour and plasma co-eluted with the biologically active form of CGRP. The circulating levels of CGRP correlated with the presence of the diarrhoea. PTHrP concentration in the tumours was one of the highest reported for any tumour although previous studies may have utilized less than optimal extraction procedures. The somatostatin analogue, octreotide (SMS 201-995), did not reduce the plasma CGRP or the diarrhoea, a finding similar to that seen in patients with medullary thyroid carcinoma and high plasma CGRP. The hypercalcaemia was also unaffected by octreotide administration. This is the first report of a prostatic tumour associated with over-production of calcitonin, PTHrP and CGRP. The major life-threatening effects of this unusual case of prostatic carcinoma were diarrhoea and hypercalcaemia. Both these effects could be tentatively ascribed to newly discovered substances, CGRP and PTHrP. With the greater availability of assays to measure CGRP and PTHrP in plasma, a detailed examination of the incidence of over-production of these substances in various cancers will be possible.

Small cell carcinoma of the prostate

This report details clinical and pathologic aspects of a patient with small cell undifferentiated carcinoma of the prostate and systemic hyperglucagonemia. A panel of potential serologic markers was evaluated in order to document additional evidence of ectopic hormonal production. Immunocytochemical markers were sought in tissue samples from the primary neoplasm and a lung metastasis. Stains were positive for corticotropin (ACTH) and gastrin in both the prostate and in the lung, but no evidence of excess secretion was documented. These findings are consistent with the notion that neuroendocrine activity is common in undifferentiated small cell carcinomas, regardless of their site of origin.

Prostatic carcinoma: histological and immunohistological factors affecting prognosis

Neuro-endocrine or paracrine cells of the human prostate and urethra have been identified by various methods, predominantly silver stains and immunocytochemistry. The incidence of neuro-endocrine differentiation in prostatic carcinoma has varied considerably from 10 to 100%, but has not been studied previously as an independent factor affecting prognosis. Nucleolar organiser regions (NORs) are loops of ribosomal RNA occurring in the nucleoli of cells which ultimately process RNA genes. NORs have been demonstrated by silver (Ag) staining techniques and have been studied in numerous malignant tumours. A pilot study from this laboratory has shown a distinct and significant difference in AgNOR staining between prostatic carcinoma and benign prostatic epithelial hyperplasia. A retrospective study was performed with at least 6 years' follow-up. This confirmed the presence of neuro-endocrine cells in more than half of the patients under investigation. A significant correlation between survival and the absence of neuro-endocrine cells was demonstrated. AgNOR staining was shown to be of no prognostic value.

The endocrine-paracrine cells of von Brunn's nests and glandular metaplasia in the supramontanal prostatic urethra

Endocrine-paracrine (EP) cells are normal cellular constituents of the human genitourinary tract. We examined the distribution and immunostaining profile of EP cells in von Brunn's nests and glandular metaplasia in the supramontanal (proximal) prostatic urethra of adult males and in prostatic ducts of the male fetal urethra. In 15/17 transurethral prostatic resection specimens there were argyrophilic cells and/or serotonin and neuronspecific enolase containing cells in von Brunn's nests/glandular metaplasia and in the supramontanal prostatic urethra. All seven fetal specimens examined contained EP cells and five had focal calcitonin immunoreactivity in prostatic ducts and ductal buds. One adult resection specimen had focal staining for human chorionic gonadotrophin and no case showed staining for somatostatin. These results further support the contention that von Brunn's nests and glandular metaplasia are probably normal urothelial variants in the adult supramontanal prostatic urethra.

Basal epithelial cells of human prostate gland are not myoepithelial cells. A comparative immunohistochemical and ultrastructural study with the human salivary gland

The hypothesis that basal epithelial cells of the human prostate are of myoepithelial origin was investigated using immunohistochemical and ultrastructural methodologies. The immunohistologic analyses show significant phenotypic differences between prostatic basal cells and myoepithelial cells of the salivary gland. Although both cell types stain intensely with the 312C8-1 monoclonal antibody, only true myoepithelial cells demonstrated significant amounts of muscle-specific actin as decorated by the HHF35 monoclonal antibody. Furthermore, using double-labeling experiments, the prostatic basal cells were strongly decorated with a fluorescein-tagged basal cell-specific keratin but were negative with the rhodamine-tagged phalloidin, a chemical that binds specifically to actin microfilaments. Ultrastructural studies also showed an absence of thin microfilament bundles, dense bodies, and micropinocytotic vesicles in the prostatic basal cells. The current investigations show that the prostatic acini do not have a basal myoepithelium. Although some authors have suggested a stem cell role for prostatic basal cells, the weight of experimental work argues against this hypothesis. The exact role of the basal epithelial cells of the prostate is not known, although they may serve endocrine, paracrine, or other regulatory functions and may be involved in modulating signals between prostatic stroma and epithelium.

Unusual prostatic carcinomas

Over 90% of malignant epithelial tumors of the prostate are common carcinomas. Uncommon or rare prostate carcinomas can histogenetically be related to 4 epithelial types of the prostate: the secretory epithelium, the basal cells, the endocrine cells and the transitional epithelium. The rare, purely mucinous carcinoma and the ductal papillary carcinoma belong to the type of secretory epithelium. The latter is rarely seen in the large central prostatic ducts, it develops more frequently in peripheral ducts and is combined with common prostate carcinoma. The so-called endometrioid carcinomas of the utriculus described in the literature are probably ductal prostate carcinomas. To date no carcinoma has been found in the utriculus. The adenoid cystic carcinoma of the prostate is a basal cell tumor with preponderantly good prognosis. Endocrine cells are disseminated in most common prostate carcinomas. Thereby mixed forms showing both portions of a common adenocarcinoma and of a carcinoid may occur. Pure carcinoids of prostate are rare findings. The small cell carcinoma of the prostate is the highly malignant variant of the endocrine cell type. Immunohistochemically, a multitude of proteohormones are demonstrable in endocrine tumor cells. The ectopic ACTH production with Cushing's syndrome is of particular clinical significance.

Amphicrine carcinoma of the lung. Diagnosis by fine needle aspiration cytology

A case of pulmonary carcinoma with dual (glandular and endocrine) differentiation diagnosed by fine needle aspiration cytology is reported. By light microscopy, the neoplastic cells showed mucicarmine, periodic-acid Schiff, and Grimelius silver positivity. On immunostaining, neuron specific enolase, chromogranin, calcitonin and serotonin were demonstrated. Electron microscopy revealed two different types of distinctive cytoplasmic inclusions in the same cell, namely: carcinoid type of neurosecretory granules and mucin droplets. Diagnostic criteria and possible histogenesis of this rare tumour entity are discussed.

Selected ultrastructural aspects of urothelial and prostatic tumors

Ultrastructural techniques have been widely applied in the study of urothelial and prostatic tumors. In the common proliferative diseases affecting the lower urogenital tract, electron microscopy has provided us with a greater understanding of the pathobiology and morphology of these disease processes. Specific diagnostic application, however, has been limited. In the unusual tumors affecting urothelium and prostate such as neuroendocrine carcinoma, carcinosarcoma, and sarcomas, electron microscopy has provided some practical diagnostic information of value in patient management. This paper provides a survey of the fundamental and practical contributions of ultrastructural studies in the prostatic and urothelial areas.

Endocrine differentiation in inflamed urinary bladder epithelium with metaplastic changes

Several types of metaplasia can occur in human bladder epithelium under certain pathological conditions. We investigated 65 cases of cystitis, associated with different types of metaplasia, for the presence of endocrine cells, using histochemical and immunocytochemical methods. Tissues were obtained at cystoscopy and were routinely fixed in 10% buffered formalin. Endocrine cells were demonstrated, between the epithelial cells, in 40 out of 50 cases of cystitis glandularis or cystica. These cells were positive by the Grimelius' silver impregnation technique and were immunoreactive for protein gene product (PGP 9.5), a new general neuroendocrine marker, chromogranin and serotonin. No endocrine cells were detected in any of the specimens of normal epithelium nor those showing squamous metaplasia. Eighteen of these cases showed prominent nerve bundles in the subepithelial tissue, as revealed by PGP immunoreactivity.

Neuroendocrine differentiation in prostatic carcinoma

Specimens from 53 cases of prostatic carcinoma obtained during total prostatectomy or transurethral resection of prostate were analyzed for neuroendocrine differentiation with immunocytochemical tests for serotonin, neuron-specific enolase, and chromogranin as well as with the Churukian-Schenk argyrophil reaction. Forty-seven per cent (25 of 53) of the prostatic carcinomas were positive for neuroendocrine differentiation, usually with an overlapping combination of these techniques. Nine per cent (five cases) contained areas with numerous neuroendocrine cells, 11 per cent (six cases) had focal scattered neuroendocrine cells, and 26 per cent (14 cases) had rare neuroendocrine cells. The positive cases spanned the histologic spectrum of prostatic adenocarcinoma; histologically none resembled a carcinoid tumor or a small cell carcinoma. Positive cases were further studied with a battery of antisera to 12 polypeptide hormones. Immunoreactivity to only bombesin (one case) and calcitonin (two cases) was detected. In five cases, neuroendocrine differentiation was studied by electron microscopy and verified at the ultrastructural level.

Endocrine cells producing regulatory peptides

Recent data on the immunolocalization of regulatory peptides and related propeptide sequences in endocrine cells and tumors of the gastrointestinal tract, pancreas, lung, thyroid, pituitary (ACTH and opioids), adrenals and paraganglia have been revised and discussed. Gastrin, xenopsin, cholecystokinin (CCK), somatostatin, motilin, secretin, GIP (gastric inhibitory polypeptide), neurotensin, glicentin/glucagon-37 and PYY (peptide tyrosine tyrosine) are the main products of gastrointestinal endocrine cells; glucagon, CRF (corticotropin releasing factor), somatostatin, PP (pancreatic polypeptide) and GRF (growth hormone releasing factor), in addition to insulin, are produced in pancreatic islet cells; bombesin-related peptides are the main markers of pulmonary endocrine cells; calcitonin and CGRP (calcitonin gene-related peptide) occur in thyroid and extrathyroid C cells; ACTH and endorphins in anterior and intermediate lobe pituitary cells, alpha-MSH and CLIP (corticotropin-like intermediate lobe peptide) in intermediate lobe cells; met- and leu-enkephalins and related peptides in adrenal medullary and paraganglionic cells as well as in some gut (enterochromaffin) cells; NPY (neuropeptide Y) in adrenaline-type adrenal medullary cells, etc.. Both tissue-appropriate and tissue-inappropriate regulatory peptides are produced by endocrine tumours, with inappropriate peptides mostly produced by malignant tumours.

Prostate-specific acid phosphatase in carcinoid tumors

Although prostate-specific acid phosphatase (PASP) has been recognized as a specific marker of tissue of prostatic origin, several investigators have pointed out that some of the carcinoid tumours and islet cell tumours of the pancreas reacted immunohistochemically to PSAP. We investigated 50 cases immunohistochemically comprising 44 carcinoids of the G-I tract, 3 of the bronchus, 1 each of the ovary, kidney and middle ear. PSAP positive cases were, 30 in G-I tract, one each in ovary and kidney. Eighty percent of tumours of hindgut origin were positive. Apart from the immunohistochemical study, the content of PSAP in preoperative serum and tumour tissue was estimated in a case with a rectal carcinoid. Extremely elevated PSAP was confirmed in both the serum and tumour tissue. Neuroendocrine tumours such as pheochromocytoma, medullary thyroid carcinoma, and islet cell carcinoma were investigated as controls. No cells immunoreactive to PSAP were observed in these control cases. Prostate specific antigen was definitely negative in carcinoids. We would emphasize that PSAP may be an excellent marker of carcinoids especially when derived from hindgut.

Prostatic adenocarcinoma evolving into carcinoid: selective effect of hormonal treatment?

Two patients, aged 72 and 65 years, each underwent two prostatic resections spaced four and two years apart, respectively. In both cases the earlier procedure showed widespread adenocarcinoma with only occasional endocrine cells, while tissue from the later operations showed prostatic carcinoids. It is suggested that the conventional adenocarcinomas were sensitive to hormonal manipulations used in treatment, but that the originally sparse carcinoid components were resistant to this form of treatment and hence became the predominant tumours. These findings imply that endocrine differentiation in prostatic carcinoma leads to lack of sex steroid sensitivity.