Carcinoid tumor of the prostate associated with adenocarcinoma

Morphologic Spectrum of Neuroendocrine Tumors of the Prostate: An Updated Review

CONTEXT.—

The incidence of neuroendocrine tumors of the prostate increases after hormonal therapy. Neuroendocrine tumors possess a broad spectrum of morphologic features and pose challenges in the pathologic diagnosis and clinical management of patients.

OBJECTIVE.—

To present a brief updated summary of neuroendocrine tumors of the prostate with an overview of their histopathologic and immunohistochemical profiles and differential diagnoses.

DATA SOURCES.—

Literature review, personal experience in the daily practice of pathologic diagnosis, and laboratory research.

CONCLUSIONS.—

Our understanding of neuroendocrine tumors of the prostate classification and diagnosis continues to evolve. These advances benefit the risk stratification and management of prostate cancer.

Phenotypic appearances of prostate utilizing PET-MRI and PET-CT with 68Ga-PSMA, radiolabelled choline and 68Ga-DOTATATE

The objective of this study was to highlight the role of multimodality imaging and present the differential diagnosis of abnormal tracer accumulation in the prostate and periprostatic tissue. Our departments have performed molecular imaging of the prostate utilizing PET-CT and PET-MRI with a range of biomarkers including F-FDG, radiolabelled choline, Ga-DOTATATE PET-CT and Ga-PSMA images. We retrospectively reviewed the varying appearances of the prostate gland in different diseases and incidental findings in periprostatic region. The differential diagnosis of pathologies related to prostate and periprostatic tissue on multimodality imaging includes malakoplakia, rhabdomyosarcoma, lymphoma, prostate cancer, neuroendocrine tumours, uchida changes, rectoprostatic fistula, synchronous malignancies, lymphocoele and schwanoma. There exists a wide differential for abnormal tracer accumulation in the prostate gland. As a radiologist and nuclear medicine physician, it is important to be aware of range of prostatic and periprostatic pathologies.

Proposed morphologic classification of prostate cancer with neuroendocrine differentiation

On July 31, 2013, the Prostate Cancer Foundation assembled a working committee on the molecular biology and pathologic classification of neuroendocrine (NE) differentiation in prostate cancer. New clinical and molecular data emerging from prostate cancers treated by contemporary androgen deprivation therapies, as well as primary lesions, have highlighted the need for refinement of diagnostic terminology to encompass the full spectrum of NE differentiation. The classification system consists of: Usual prostate adenocarcinoma with NE differentiation; 2) Adenocarcinoma with Paneth cell NE differentiation; 3) Carcinoid tumor; 4) Small cell carcinoma; 5) Large cell NE carcinoma; and 5) Mixed NE carcinoma - acinar adenocarcinoma. The article also highlights "prostate carcinoma with overlapping features of small cell carcinoma and acinar adenocarcinoma" and "castrate-resistant prostate cancer with small cell cancer-like clinical presentation". It is envisioned that specific criteria associated with the refined diagnostic terminology will lead to clinically relevant pathologic diagnoses that will stimulate further clinical and molecular investigation and identification of appropriate targeted therapies.

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.

Primary carcinoid tumor of the prostate with concurrent adenocarcinoma: a case report

Prostatic adenocarcinomas commonly exhibit neuroendocrine differentiation as demonstrated by immunohistochemistry. However, true carcinoids of the prostate are rare. We describe herein a case of a primary carcinoid occurring synchronously with a conventional adenocarcinoma in the prostate of a 66-year-old man. The carcinoid measured 0.2 x 0.2 cm and did not show contiguity with adjacent conventional, moderately differentiated adenocarcinoma. Immunohistochemical stains for chromogranin and neuron-specific enolase were strongly immunoreactive in the carcinoid but not in the adenocarcinoma. Both neoplasms demonstrated positive staining for prostatic acid phosphatase and prostate-specific antigen. Owing to the relatively minute size of the carcinoid, the possibility that this tumor will impact negatively on the patient's overall prognosis is not anticipated.

Primary carcinoid tumour with ossification masquerading as calyx stone in a horseshoe kidney

A case of renal carcinoid tumour arising within a teratoma in a horseshoe kidney in a 23-year-old male is reported. The presenting symptom was abdominal pain, and bone tissue within the tumour was initially misinterpreted as a calyx stone, leading to unsuccessful attempts at extracorporeal shock-wave lithotripsia and percutaneous lithotripsia. This unusual tumour is over-represented in patients with horseshoe kidney and other congenital developmental renal defects.

Primary carcinoid of the kidney

A rare case of primary renal carcinoid tumour is presented. The diagnosis was based on immunohistochemically diffuse cytoplasmic positivity for chromogranin A and neuron-specific enolase, in addition to histologic findings. Only 14 previous cases of this tumour have been documented in the literature.

Neuroendocrine cells in the normal, hyperplastic and neoplastic prostate

Neuroendocrine cells can be demonstrated in normal, hyperplastic and neoplastic prostatic tissues. The products secreted by these cells can be used as tissue and/or serum markers but may also have biological effects. Neuroendocrine cells in prostate cancer most probably do not contain the androgen receptor and are therefore primarily androgen independent. Some of the neuropeptides secreted by the neuroendocrine cells may act as growth factor by activation of membrane receptors in an autocrine-paracrine fashion or by ligand-independent activation of the androgen receptor in neighboring non-neuroendocrine cells. Evidence is accumulating from experiments with tumor models that neuropeptides indeed can influence the growth of prostatic tumor cells. Future research on neuroendocrine differentiation may answer some questions concerning the biological behavior of clinical prostatic tumors.

Composite glandular-endocrine cell carcinoma of the extrahepatic bile duct: immunohistochemical study

A composite glandular-endocrine cell carcinoma of the extrahepatic bile duct in a 64 yr old Japanese man is reported. A nodular polyp measuring 1.9 x 1.1 cm was located in the confluence of the extrahepatic bile duct. Histologically, the tumor was composed of well differentiated tubular adenocarcinoma and small cell neuroendocrine carcinoma with a transition between the 2 components. The 2 areas of the tumor immunohistochemically revealed a clear-cut difference in functional differentiation. Tumor cells in the glandular component were immunoreactive to both carcinoembryonic antigen (CEA) and CAM 5.2, while those in the small cell area were immunoreactive to neuroendocrine markers such as neuron specific enolase (NSE), chromogranin A and serotonin. These results suggest that the tumor arose from a multipotential stem cell capable of differentiation in 2 directions.

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.

Primary urinary cytodiagnosis of a bladder small-cell carcinoma

A small-cell undifferentiated tumor of the bladder in a 69-yr-old man with asymptomatic hematuria is described. Urine cytology showed abundant, small, round-to-oval hyperchromatic cells with coarse chromatin, nuclear molding, and high nuclear/cytoplasmic ratios. A primary cytodiagnosis of small-cell undifferentiated cancer with associated severe urothelial atypia was made. Immunohistochemical stains were negative for neuron-specific enolase, leukocyte common antigen, chromogranin, epithelial membrane antigen, prostatic acid phosphatase, and prostate-specific phosphatase. The diagnosis was confirmed histologically by studies performed on cystoscopic bladder biopsy material.

Grossly elevated serum prostatic acid phosphatase in a patient with carcinoid

We report a case of carcinoid, diagnosed histochemically and biochemically, which was associated with grossly elevated serum prostatic acid phosphatase and normal serum prostate specific antigen.

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 tumor of the vulva

We resected a vulvar tumor, present for five years, from a 75-year-old female, and performed light and electron microscopy. Simultaneous proliferation of exo-, endo- and amphicrine cells was demonstrated. Based on histological evidence, the case is considered as a hitherto undescribed amphicrine tumor of the vulva.

Primary carcinoid tumor of kidney. Light and electron microscopy, and immunohistochemical study

We present a case of primary renal carcinoid tumor with the appearance of type B carcinoid with trabecular and ribbon-like structure. All the immunohistochemical stains were negative. Electron microscopy revealed numerous cytoplasmic granules with polar distribution and masses of intermediate microfilaments. We believe only 8 cases have been reported in the literature.

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.

Objective response of malignant carcinoid to radiation therapy

In a retrospective review, we were able to identify records for 18 patients who were treated for malignant carcinoid in our Departments of Radiation Oncology from 1974-1985. At postmortem examination, one was found not to have malignant carcinoid. In 4 cases irradiation was administered postoperatively to patients whose subsequent courses did not permit assessment of objective response. Using standard criteria for objective response, an objective response rate of 54% was observed in the 13 cases whose records were adequate to make this assessment. Of the 7 responses, 3 were complete within the treated field as judged by clinical findings (2 patients) or postmortem examination (1 patient). Of the 6 nonresponders, 2 interrupted treatment prematurely, 2 were treated to a planned dose of only 2000 and 2500 cGy, and 2 were treated palliatively to limited ports which included only partial volumes of tumor. We conclude that radiation therapy is an effective treatment modality with a high rate of objective response in the management of those patients with malignant carcinoid tumors who require non-surgical, anti-neoplastic therapy.

Peptide-hormone- and serotonin-immunoreactive tumour cells in carcinoma of the prostate

In order to establish the extent of neuroendocrine differentiation and the occurrence of neurohormonal peptides in the neoplastic cells of prostatic carcinomas, silver-staining and immunocytochemical techniques were used. All gave satisfactory results. The incidence of the neuroendocrine cells seemed to be higher in the fresh "Bouin-fixed" biopsy specimens than in the conventionally "formalin-fixed" specimens from archival paraffin blocks. All carcinomas demonstrated argyrophil cells as an integral element of the tumour. In highly differentiated carcinomas (grade I) these cells were scattered focally, intermingled with non-argyrophil cells in typical adenocarcinomas; their incidence was estimated to be about the same as in benign prostatic hyperplasia. Most of them were immunoreactive with antisera raised against serotonin and/or TSH (thyroid stimulating hormone). In moderately and poorly differentiated (grades II-III) carcinomas, however, the argyrophil cells were more numerous and showed greater variation in growth pattern; only occasionally they displayed a typical carcinoid-like structure. Moderately and poorly differentiated carcinomas also showed a greater variation in the number and kinds of peptide immunoreactivities than the highly differentiated carcinomas. In addition to serotonin- and TSH-immunoreactive cells as the most prevalent type, now also human chorionic gonadotrophin (HCG-alpha), adrenocorticotropic hormone (ACTH), leu-enkephalin, beta-endorphin, somatostatin, glucagon and calcitonin immunoreactive cells could be found within certain tumour areas and often with a distinctly patchy distribution. In two cases, where the tumour cells in the metastases were also investigated, they were found to be both argyrophil and immunoreactive with the same antisera as those of the primary tumour. Our findings emphasise the fact that prostatic carcinomas are more complex and heterogenous than previously thought, exhibiting endocrine differentiation as an integral element of virtually all prostatic adenocarcinomas.

Small cell carcinoma of the prostate. Part I. A clinicopathologic study of 20 cases

Clinical information and histological slides of 20 cases of small cell carcinoma of the prostate seen at The University of Texas M. D. Anderson Hospital and Tumor Institute at Houston over a 23-year period were reviewed. Patient's ages ranged from 30 to 89 years (median, 67 years). In nine cases, pure adenocarcinoma of the prostate preceded recognition of the small cell component by 7 months to 8 years (median, 18 months); five of these were initially at Stage A. There was a small cell component at presentation in 11 cases (10, Stage D). Small cell carcinoma was merging with the adenocarcinoma in 11 cases and represented 30% to 90% of total tumor volume. Eleven of 20 patients died of their disease. Those presenting initially with a pure adenocarcinoma survived between 7 months and 9 years (median, 24 months). After the recognition of the small cell carcinoma component, regardless of a prior history of adenocarcinoma, death followed within 1.5 years (median, 5 months). This study suggests a biologic difference in behavior in prostatic carcinoma containing a small cell carcinoma component. The small cell component may manifest early or late in the disease.

Argyrophilic adenocarcinoma of the prostate with Paneth cell-like granules

A prostatic adenocarcinoma with argyrophilia and many Paneth cell-like granules in a 91-year-old man is reported. The initial symptom was pollakisuria, and the laboratory data showed no significant abnormality except for moderate anemia. Through radiologic examinations a right hydronephrosis and metastatic cancer of the lumbar vertebra were suspected. Because prostatic cancer was suspected, a needle biopsy of the prostate was performed. Routine histologic examinations revealed a moderately differentiated adenocarcinoma of the prostate. By hematoxylin and eosin stain, eosinophilic large granules like those of Paneth cells were found in many cancer cells. In addition, argyrophilic cancer cells were seen by Grimelius' stain. Immunoperoxidase staining elucidated a definite reactivity for lysozyme in the granules like Paneth cells. Ultrastructurally, the granules of Paneth cell-like cancer cells were electron-dense spherical bodies with a medium diameter of 540 nm. Prostatic adenocarcinoma with argyrophilia is rare, and the argyrophilic adenocarcinoma with Paneth cell-like granules is very rare in the prostate.

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.

Small cell carcinoma of the prostate gland with inappropriate antidiuretic hormone secretion: morphological, immunohistochemical and clinical expressions

Small cell carcinomas of the prostate gland are rare, and their histogenesis and clinical behavior remain poorly defined. We report a case with antidiuretic hormone secretion, which demonstrates direct transformation of the adenocarcinoma into the small cell component. The adenocarcinoma reacted positively for prostatic antigen, and negatively for carcinoembryonic antigen and neuron specific enolase, whereas the small cell component was negative for prostatic antigen, and positive for carcinoembryonic antigen and neuron specific enolase. At biopsy this was interpreted as denoting 2 separate tumors: one of prostatic and the other of nonprostatic origin. The clinical course was rapidly fatal but otherwise manifested the metastatic pattern of prostatic carcinoma. We caution that immunohistochemical reactions may be misleading if not interpreted in the context of other findings in the case. This case is labeled as a small cell carcinoma rather than a poorly differentiated adenocarcinoma of the ordinary type because the tumor exhibited morphological, immunohistochemical and biological features typical for that neoplasm.

Argyrophilic prostatic carcinoma. Case report with literature review on prostatic carcinoid and "carcinoid-like" prostatic carcinoma

An unusual prostatic neoplasm characterized by a carcinoid-like light microscopic pattern together with argyrophilia of tumor cells is described. Immunoperoxidase stain for prostatic specific antigen, however, was positive, indicating that this neoplasm was an argyrophilic prostatic carcinoma. Although the clinical significance of a carcinoid-like pattern and/or argyrophilia in prostatic carcinoma is currently unknown, pathologic recognition of these features is of paramount importance because prostatic carcinoma with these features has to be distinguished from true primary prostatic carcinoid tumor or, in areas of metastasis, from metastatic carcinoid originating from other sites such as the gastrointestinal or respiratory tracts. The value of the immunoperoxidase technique for prostatic specific antigen as well as prostatic acid phosphatase in this differentiation is stressed.

Histopathology of prostate carcinoma. Diagnosis and differential diagnosis

The prognosis of prostate cancer depends largely on the degree of differentiation. Therefore the pathologist plays an important part in diagnosis and therapeutic decisions. There are three different growth patterns: glandular, cribriform, and solid-undifferentiated. In the glandular pattern, well and poorly differentiated forms are to be distinguished. Well differentiated adenocarcinomas are observed predominantly in benign nodular hyperplasia as incidental carcinomas. In case of differentiation from benign proliferations, the behaviour of the cellular nucleus--size, form, and characteristics of nucleolus--is decisive. Inflammatory stromal reaction is always absent. The growth pattern and degree of nuclear atypia determine the degree of malignancy to be demonstrated in a score. In clinically manifest carcinomas, pluriform patterns are prevailing. The lowest degree of differentiation of each case counts for the grading. In incidental carcinomas, the extension of the carcinoma has to be determined by the resection material. Here the nodular carcinoma represents a special form primarily located in the centre and obviously developing from a nodular hyperplasia. The differential diagnosis of prostatic cancer may cause great problems. Primary and secondary--postatrophic--hyperplasias may be similar to a glandular and cribriform carcinoma. Atypical hyperplasias of irregular nuclear pattern are present. Carcinoma in situ is not the proper term for such proliferations. Concerning rare types of prostate carcinomas, the urothelial carcinoma, the carcinoma with argentaffine cells, so-called endometrioid carcinomas, and squamous cell carcinomas are of importance. Following conservative, antiandrogen and radio-therapy characteristic regressive alterations can be observed in the prostate carcinoma. Response and resistance to therapy of the local tumor growth may be assessed during follow-up. A grading system is proposed for this purpose. Among all markers immunohistochemically demonstrable, only the presence of acid prostate phosphatase and prostate-specific antigen is of practical diagnostic importance in prostate cancer up to now.

Insular carcinoid of ovary associated with malignant mucinous tumors

Ovarian carcinoids are frequently encountered in association with mucinous cysts and occasionally with mucinous cystadenomas. From a series of more than 200 ovarian carcinoids, this report describes 2 cases of insular carcinoid, 1 of which arose in a cystadenoma of borderline malignancy and the other in a mucinous adenocarcinoma. Histogenesis, histologic patterns, and natural history of carcinoid are discussed.

Endocrine-paracrine cells of the prostate and prostatic urethra: an ultrastructural study

A remarkable morphologic diversity among the endocrine-paracrine (EP) cells of the prostate and prostatic urethra was found in this study. Based on granule morphology, a wide variety of EP cell "types" was discerned, although many intermediate and mixed cells, forming a continuum, were also observed. The EP cells were of both the open (containing luminal borders) and closed types. The latter often had long dendritic processes. Prominent lamellar bodies, possibly representing a form of crinophagy, were present in some EP cells. The variety and morphologic complexity of these prostatic and urethral EP cells suggest that they play an important role in both normal and pathologic conditions.

Prostatic adenocarcinoma with carcinoidal features producing adrenocorticotropic syndrome. Immunohistochemical study and review of the literature

An autopsy case of disseminated, military-type, composite adenocarcinoma and carcinoid tumor associated with adrenocorticotropic syndrome is discussed. Prostatic origin and functional activity were demonstrated by immunohistochemical techniques. Of interest in this case is that the tumor had the characteristics of amine precursor uptake and decarboxylation (APUD) cells and also kept the antigenicity of its prostatic origin. The APUD system perhaps should be considered as one form of functional differentiation of cells of different origin rather than an exclusive derivative of the neural crest.

Tumors of the diffuse endocrine system, histochemical and electron-optic aids, and pitfalls in diagnosis

Tumors of the Diffuse Endocrine System are a heterogeneous group of malignant neoplasms which have rather characteristic light microscopic and cytologic features. These are, however, not diagnostic and their identification with separation from non-neuroendocrine carcinomas require important adjunctive evaluations including histochemical analysis, immunocytochemical characterization and electron-optic identification of endocrine secretory products and paracrine effects in the cytoplasm of the neoplastic cells. The importance of proper classification cannot be over-emphasized because of the often considerable biologic and prognostic differences between neuroendocrine carcinomas and other types of carcinoma, notably metastatic carcinomas from the breast and the prostate. Furthermore, the separation of these lesions into two groups; a small cell type and those with large cells (carcinoid type) appears to have clinical significance in both diagnosis and response to therapy.

Endocrine cells in the prostate gland, urothelium and Brenner tumors. Immunohistological and ultrastructural studies

Endocrine cells are a normal constituent of the prostate gland, prostatic urethra and urinary bladder mucosa. Positive results using immunohistochemical technics were obtained only with antiserotonin antibodies. In normal tissues, there was a close similarity between the distribution of argyrophilic cells (Grimelius) and serotonin-storing cells. Some striking features were the patchy distribution of endocrine cells, the presence of slender cytoplasmic processes occasionally reaching the luminal surface and the paucity of specialized cells in bladder mucosa. It is unlikely that endocrine cells participate in conventional neoplasms of prostate and bladder. Exceptions are lobular hyperplasia, certain adeno-carcinomas of prostate and inverted papilloma of bladder. An ultrastructural study permitted the distinction of two types of endocrine cells characterized by a different morphology of their granules. Another relevant finding was the presence of serotonin-storing cells in Brenner tumors. The latter observation emphasizes the close similarity between this neoplastic epithelium and urothelium. This implies that endocrine cells may be of mesodermal derivation.

Carcinoid tumor of the gallbladder associated with adenocarcinoma

A case of carcinoid tumor of the gallbladder associated with adenocarcinoma in a 56-year-old man is reported and a review of the literature is made. The tumor was a polypoid mass with a size of 5.5 X 4.0 X 2.8 cm. Histologically, the tumor showed carcinoid and adenocarcinoma with areas of mucous change. Tumor cells containing argyrophil granules were observed in both carcinoidal and adenocarcinomatous areas, but no argentaffin granules were detected in either of the neoplastic areas. Some of the tumor cells had both argyrophil granules and mucin in the same cytoplasm. The electron microscopic study revealed several tumor cells containing neurosecretory granules; however, no clinical signs of hormonal activities of the tumor were observed. The patient died of generalized bone metastases 16 months after surgery. This appears to be the second case of composite tumor of the gallbladder.

Primary anaplastic small cell (oat cell) carcinoma of the larynx. Review of the literature and report of 18 cases

Anaplastic small cell (oat cell) carcinoma is a neoplasm commonly arising in the lungs. However, it may also occur, though rarely, in the larynx. A series of 43 cases is presented (ten cases from the Armed Forces Institute of Pathology, eight from the Department of Otolaryngology of the Padua University, and 25 from the literature). The tumor often presents in the sixth and seventh decades of life and appears to be highly aggressive, and metastases develop early. The most common presenting symptom is hoarseness. As in pulmonary small cell carcinoma, prognosis is poor and does not seem to depend upon therapeutic modalities, tumor location or the extent of initial local disease. The tumor seems to derive from the Kulchitsky cell present not only in the bronchial mucosa but also in the laryngeal lining. Like pulmonary anaplastic small cell carcinoma, small cell carcinoma of the larynx should be treated with systemic chemotherapy and radiotherapy. The association of small cell carcinoma with squamous carcinoma of the larynx is also reported and problems connected with the histogenesis of this mixed tumor are discussed.

Carcinoidal tumor of the kidney

Two cases of primary renal carcinoidal tumor are reported. One was discovered in a 32-year-old pregnant woman. The other tumor was retrospectively diagnosed 3 years after nephrectomy in a 65-year-old woman who was hospitalized with a metastatic lesion in her lumbar spine. Both tumors are compared with 5 other cases previously reported in the literature, and hypotheses about the cause of renal localization of this tumor are reviewed.

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

Two types of endocrine-paracrine (EP) cells have been detected histochemically and ultrastructurally in normal and hyperplastic prostates; i.e. type I cells resembling intestinal EC (enterochromaffin) cells and type 2 cells similar to urethral EP cells previously reported by Casanova et al. (1974). About one-third of the 40 prostatic carcinomas studied contained EP cells: two of these were composite tumours exhibiting both adenocarcinomatous and carcinoid patterns. These four tumours have also been studied histochemically and ultrastructurally. ACTH and beta-endorphin immunoreactive cells, ultrastructurally resembling pituitary corticotrophic cells, have been identified in three tumours. Cells identical with type I and type 2 cells of the normal prostate were detected in two cases and in a further case, respectively.

Cervical carcinoid ("argyrophil cell" carcinoma) associated with an endocervical adenocarcinoma: a light and ultrastructural study

On microscopic examination of a cervical carcinoid removed from a 29-year-old woman, foci of endocervical adenocarcinoma in situ (AIS) and severe squamous dysplasia were present immediately adjacent to the invasive carcinoid tumor. Cells of the carcinoid tumor contained abundant intracytoplasmic argyrophilic granules and numerous neurosecretory granules (NSG) on ultrastructural study. Neoplastic cells of the endocervical AIS were devoid of argyrophilic granules and contained no NSGs. The present neoplastic process appeared similar to cases of a "mixed" type neoplasm composed of a carcinoid tumor and an adenocarcinoma, which have been reported from several areas of the body but only once previously from the cervix. The possible mechanisms accounting for such an unusual neoplastic process are discussed.