Prostatic origin of metastases: immunoperoxidase localization of prostate-specific antigen

Practical Applications in Immunohistochemistry: Carcinomas of Unknown Primary Site

CONTEXT

-Identification of the site of origin of carcinoma of unknown primary using immunohistochemistry is a frequent requirement of anatomic pathologists. Diagnostic accuracy is crucial, particularly in the current era of targeted therapies and smaller sample sizes.

OBJECTIVES

-To provide practical guidance and suggestions for classifying carcinoma of unknown primary using both proven and new antibodies, as well as targeting panels based on integration of morphologic and clinical features.

DATA SOURCES

-Literature review, the authors' practice experience, and authors' research.

CONCLUSIONS

-With well-performed and interpreted immunohistochemistry panels, anatomic pathologists can successfully identify the site of origin of carcinoma of unknown primary. It is crucial to understand not only the diagnostic uses of the many available antibodies but also the potential limits and pitfalls.

Structural heterogenity of intraluminal content of the prostate: a histochemical and ultrastructural study

Intraluminal contents of benign and malignant prostatic tissue are associated with varying forms of acellular structures. These include corpora amylacea, prostatic calculi, and prostatic crystalloids. There are relatively few microscopy studies about the characterization of intraluminal structures from benign and malignant prostatic glands and little is known about their chemical composition. In the present study, we used a combination of special histochemical methods, immunohistochemistry, and transmission electron microscopy to characterize intraluminal contents of benign and malignant prostate glands. The study was done on 33 radical prostatectomy and four transurethral resections of prostate specimens. Histochemical methods such as von Kossa, autometallography (AMG), as well as PSA immunohistochemistry and transmission electron microscopy were performed to characterize intraluminal contents of benign and malignant prostate glands. Von Kossa staining was observed in acellular structures, corpora amylacea, prostatic calculi, and calcified blood vessels. AMG staining was observed in the lumen of small glands, in the epithelium lining prostate glands, and corpora amylacea. PSA staining showed prostatic glands with both positive and negative corpora amylacea and epithelial cells. Ultrastructural observation revealed the presence of a variety of highly heterogeneous aggregates composed of fibrillar elements that were similar to those of amyloid.

The source of pretreatment serum prostate-specific antigen in clinically localized prostate cancer--T, N, or M?

PURPOSE

Prostate-specific antigen (PSA) is an important marker for prostate cancer and has been shown to be secreted from the primary tumor and from metastases. However, the relative contribution of the primary and micrometastatic disease to the serum level of PSA in patients with clinically localized disease has not been delineated. This study addresses the source of pretreatment serum PSA in patients with clinically localized disease.

METHODS AND MATERIALS

The fall in serum PSA level following radical prostatectomy (280 patients; 105 T1, 165 T2, 10 T3) or definitive radiotherapy (427 patients; 122 T1, 147 T2, 158 T3/T4) was analyzed with the assumption that any fall in PSA following local treatment reflects the fraction of PSA produced in the prostate and its primary tumor.

RESULTS

Serum PSA level became undetectable in 277 of the 280 (99%) patients within 6 months of radical prostatectomy. The three patients who did not achieve undetectable levels had postsurgical values < or = 0.9 ng/ml. Following definitive radiotherapy, nadir serum PSA values were between < or = 0.3 and 20.3 ng/ml, with mean and median values of 1.9 and 1.2 ng/ml, respectively. Nadir PSA was undetectable in 52 patients (12%). Four patients' PSA did not fall, but rose from the start, and each developed metastatic disease within 9 months, and in each metastases appeared to contribute to pretreatment serum PSA. In the remaining patients, the maximal factor by which PSA fell to its nadir was higher the higher the pretreatment PSA level. We present arguments that this is most consistent with the hypothesis that virtually all detectable pretreatment serum PSA derives from the primary tumor. Confirmatory evidence that little of the pretreatment serum PSA came from metastases was obtained by extrapolating the rising PSA profile in 97 patients back to pretreatment time. Back-extrapolated PSA contributed a mean of 7% and a median of 5% to the pretreatment serum value. Because such back-extrapolated values estimate the potentially maximal micrometastatic contribution, metastatic disease at diagnosis contributes little to pretreatment serum PSA.

CONCLUSION

In patients with clinically localized prostate cancer, putative micrometastatic disease contributes negligibly to the pretreatment serum PSA level even when the latter is high. Most likely such patients, when they have metastases, have a very low metastatic burden.

Prostate specific antigen and gleason grade: an immunohistochemical study of prostate cancer

Prostate cancer is histologically heterogeneous as reflected in the 5 patterns of the Gleason grading system. Gleason grade correlates with volume, extent and prognosis. Serum prostate specific antigen (PSA) levels also correlate with tumor volume but the degree to which grade correlates with PSA has not been precisely defined. To quantify this relationship further, we prepared maps of each grade of cancer in 86 radical prostatectomy specimens from patients with clinical stage T2 cancer. The median per cent of the volume of cancer per prostate composed of grade 1 was 0%, while it was 1% for grade 2, 84% for grade 3, 5% for grade 4 and 0% for grade 5. We stained 95 cancer foci (grades 1 to 5) in 40 of these specimens for PSA. The presence and intensity (0 to 3+) of staining in more than 33,000 acini (or cells) correlated inversely with grade (p < 0.0001). Nearly all acini in grade 1 and most in grade 2 stained positive (2 to 3+) for PSA; 87% were positive but with less intensity in grade 3. While many grade 4 (79%) and grade 5 (49%) cells were positive, the intensity of staining was weak. Serum PSA levels correlated with total tumor volume (r = 0.67) but serum PSA levels per cm.3 of cancer decreased with increasing grade (r = -0.24 and p < 0.02). These studies confirm the strong inverse correlation between Gleason grade and the PSA content of prostate cancer. Since more than 85% of grade 3 acini stained for PSA and grade 3 made up the largest portion (84%) of cancer, the predominant contributor to serum PSA levels from prostate cancer was Gleason grade 3. The other grades contribute relatively little to the serum PSA levels either because of the small volume (grades 1 and 2) or the diminished PSA content (grades 4 and 5).

Splenic metastasis in hairy cell leukemia

BACKGROUND

Splenic metastasis is uncommon and usually occurs in the setting of widespread visceral metastasis. Splenic metastasis as an initial manifestation of disease and sole site of metastasis has not been reported previously.

METHODS

The authors describe a patient with hairy cell leukemia (HCL) with the unexpected finding of metastatic adenocarcinoma in the spleen. Direct inspection at the time of laparotomy and subsequent radiographic studies did not show a primary or additional metastatic tumor. Eventually, he manifested evidence of pulmonary and hepatic metastases and died with fungal sepsis.

RESULTS

The splenectomy specimen showed HCL and metastatic adenocarcinoma. Immunohistochemical studies showed adenocarcinoma with diffuse cytoplasmic staining for prostate-specific antigen and focally positive results with prostatic acid phosphatase antigen. Postmortem examination 9 months later showed HCL and widespread metastatic adenocarcinoma. No primary tumor was identified, and multiple tissue blocks of the prostate had negative findings for tumor.

CONCLUSIONS

The immunohistologic features of the metastatic adenocarcinoma were interpreted as prostatic in origin. The pattern of isolated metastatic disease in the absence of primary tumor appears to represent another possible atypical disease presentation of prostatic cancer. Hairy cell-induced structural and immunologic alterations within the splenic microenvironment may have contributed to this unique clinical presentation.

Prostate specific antigen: a critical assessment of the most useful tumor marker for adenocarcinoma of the prostate

PSA is a kallikrein-like, serine protease that is produced exclusively by the epithelial cells of all types of prostatic tissue, benign and malignant. Physiologically, it is present in the seminal fluid at high concentration and functions to cleave the high molecular weight protein responsible for the seminal coagulum into smaller polypeptides. This action results in liquefaction of the coagulum. PSA is also present in the serum and can be measured reliably by either a monoclonal immunoradiometric assay or a polyclonal radioimmunoassay. The calculated half-life of serum PSA ranges from 2.2 to 3.2 days and the metabolic clearance rate of this tumor marker follows first-order kinetics. Digital rectal examination, cystoscopic examination and prostate biopsy all can cause spurious elevations of the serum PSA concentration. Conditions such as bacterial prostatitis and acute urinary retention also can falsely elevate the serum PSA level. Because approximately 25% of the patients with BPH only will have an elevated serum PSA concentration and BPH tissue contributes to this PSA value in a variable manner from patient to patient, it is unlikely that PSA by itself will become an effective screening tool for the early diagnosis of prostate cancer. However, if combined with digital rectal examination and/or transrectal ultrasound it may become a vital part of any early detection program. Prostatic intraepithelial neoplasia also may be associated with moderately elevated serum PSA levels. Although there is a direct correlation between the serum PSA concentration and clinical stage, PSA is not sufficiently reliable to determine the clinical stage on an individual basis. This finding also applies to pathological stage. As a result, the preoperative serum PSA concentration cannot be used to decide whether to recommend radical prostatectomy for potential cure. Low preoperative serum PSA concentrations in patients with previously untreated prostate cancers are predictive of a negative bone scan. Thus, in these select patients a staging bone scintigram may not be necessary. With respect to monitoring patients after definitive therapy, PSA is an exquisitely sensitive tumor marker. Irrespective of the treatment modality (radical prostatectomy, radiation therapy or antiandrogen treatment), PSA reflects accurately the tumor status of the patient and is prognostic of eventual outcome; this tumor marker is capable of predicting tumor recurrence months before its detection by any other method. PSA is also a most useful immunocytochemical marker. Its sensitivity and specificity to identify tissue of prostatic origin approach 100%. When compared to PAP, PSA is a more precise and meaningful marker in all clinical situations.(ABSTRACT TRUNCATED AT 400 WORDS)

Combined immunohistochemical study of tissue polypeptide antigen and cancer antigen 125 in human ovarian tumours

An indirect immunoperoxidase method was used to study the expression of tissue polypeptide antigen (TPA) and cancer antigen 125 (CA 125) in 47 benign and malignant ovarian tumours. Tissue polypeptide antigen and CA 125 antigen were expressed respectively in 22 (73%) and 16 (53%) of the 30 adenocarcinomas and in five (29%) and four (23%) of the 17 benign tumours. Co-expression of TPA and CA 125 antigen occurred in 12 (40%) malignant and four (23%) benign tumours. Ultrastructurally, TPA and CA 125 antigens were located at the cell surface and microvillous surfaces. Evaluation of combined TPA and CA 125 antigen results revealed a remarkable improvement in the positivity rate and a significant decrease (P less than 0.05) in the negativity rate of ovarian carcinomas as compared with the result of each one separately. These findings provide complementary evidence for the previous results on the plasma levels of TPA and CA 125 antigen and suggest that specific combinations of tumour markers may be more effective for the diagnosis and monitoring of ovarian carcinomas, than the use of any single marker.

Serum prostate-antigen levels in patients with benign prostatic hypertrophy treated with leuprolide

We studied serum prostate-specific antigen levels in 12 men with benign prostatic hypertrophy treated with a long-acting GnRH analogue, leuprolide, 1 mg (0.2 mL) sc. daily for six months. The average decrease in prostate size measured by ultrasound was 45 percent after six months with concomitant improvement in the obstructive symptoms of prostatism. There was a steady decline in serum PSA levels which paralleled the decrease in prostate size. One patient who discontinued treatment after six months demonstrated both a regrowth of his prostate and a rise in serum PSA levels to pretreatment levels four months post-discontinuation of treatment. We conclude that treatment with a GnRH analogue caused reversible involution of prostatic epithelial cells with parallel effects on serum PSA levels. Consideration of the initial prostate size together with the serum PSA levels can help predict the response to medical castration in men with BPH.

Mucinous Adenocarcinoma of the Prostate Presenting as a Retrovesical Cyst

A 63-year-old man presented with acute urinary retention due to a retrovesical cystic tumor. Investigation revealed mucinous prostatic adenocarcinoma with metastatic involvement of testis and epididymis. He was treated with retrovesical tube drainage, bilateral orchiectomy and epididymectomy and cyproterone acetate.

Immunocytochemical localisation of prostate-specific antigen: specificity and application to clinical practice

An immunocytochemical method to localise prostate-specific antigen (PSA) in paraffin sections was used to establish the prostatic origin of both primary and metastatic tumours. The specificity of the technique was confirmed in 65 known primary (63 PSA-positive) and 17 metastatic prostatic carcinomas (16 PSA-positive). Thirteen non-prostatic primary carcinomas and a series of benign proliferative and malignant conditions which might be considered in the morphological differential diagnosis of prostatic adenocarcinoma were PSA-negative. The technique has now been applied diagnostically to tumour tissue resected from 21 patients. These neoplasms of the base and neck of the bladder could not be categorised as prostatic or urothelial in origin by clinical and endoscopic assessment or by conventional histopathology. In 11 patients such tumours were PSA-positive, indicating a prostatic origin. In two further patients, the prostatic origin of lymph node secondaries was confirmed in the absence of a clinically apparent primary. The technique is a valuable adjunct to conventional histopathology.

Immunohistochemical localization of T antigen-like substance in benign hyperplasia and adenocarcinoma of the prostate

Peanut agglutinin was used in a lectin-anti-lectin immunoperoxidase technique to assess the status of T antigen-like substance in histological sections of benign hyperplasia and adenocarcinoma of the prostate. Of 30 benign lesions 26 (86.7 per cent) had negative staining in the glandular epithelia and 4 showed uneven staining of the epithelial cells in a small proportion of the glands. Additionally, 15 of 30 benign lesions (50 per cent) had positive staining restricted to the basal myoepithelial cells in a variable proportion of the glands. All benign lesions demonstrated the presence of normal cryptic T antigen after neuraminidase digestion. Of 25 adenocarcinomas 14 (56 per cent) were positive and 7 (25 per cent) were negative for T antigen but demonstrated the presence of normal cryptic T antigen after neuraminidase digestion, and 4 (16 per cent) were negative for T and cryptic T antigens. Of 8 grade 1, 9 grade 2 and 8 grade 3 tumors, and 9 tumors from patients with bone metastases 3 (37.5 per cent), 8 (88.9 per cent), 7 (87.5 per cent) and 7 (77.8 per cent), respectively, were positive for T antigen or negative for T and cryptic T antigens. The results show a correlation between the status of T antigen-like substance and tumor grade as well as metastasis in patients with prostatic carcinoma.