Cytomorphology, immunoprofile, and clinicopathologic correlation of metastatic prostatic carcinoma

Exploring the efficacy of AMACR, ERG, and AR immunostains in prostatic adenocarcinoma and their association with novel grade groups

The study examines the utility of AMACR, ERG, and AR immunostains in diagnosing prostatic adenocarcinoma (PCa) and assessing prognosis in comparison to the Gleason score and new WHO grading groups. Seventeen PCa biopsies and five benign prostatic hyperplasia (BPH) biopsies were analyzed. Immunoreactivity, scored from 1 to 3 based on percentage of positive cells and intensity of expression, was assessed, revealing 76.47% positivity for AMACR, 35.29% for ERG, and 94.12% for AR in PCa cases, with variable scores and intensity among markers and grade groups. AMACR sensitivity and ERG specificity were noted. Higher-grade PCa exhibited increased positivity for both markers, indicating prognostic significance. In BPH cases, AMACR showed positivity in 2 cases, ERG in 1, and AR in all cases, albeit with lower expression. Differential expression was observed among immunomarkers and grade groups of malignancy. AMACR and ERG stains serve as sensitive and specific markers for PCa diagnosis and prognosis. Their increasing positivity with higher-grade groups underscores prognostic value. These findings highlight the importance of immunostains in refining PCa diagnosis and prognostication.

Experience and Lessons Learned in the Treatment of Transforming Small Cell Neuroendocrine Carcinoma of the Prostate: A Case Report and Literature Review

Introduction

Small cell neuroendocrine carcinoma of the prostate (SCNECP) is a rare and highly malignant tumor that commonly transforms into conventional prostate adenocarcinoma (CPAC). Most of SCNECP cases cannot be detected and diagnosed early, and SCNECP is often diagnosed when there is liver and lung metastasis. Therefore, the early detection of the process from CPAC to SCNECP is crucial.

Case Report

We present a case of a 73-year-old man who was initially admitted to our hospital with metastatic CPAC. He was administered goserelin acetate 3.6 mg combined with bicalutamide tablets (50 mg) once daily for endocrine therapy and docetaxel (100 mg) combined with prednisone (5 mg) twice a day. After treatment, the prostate-specific antigen (PSA) level decreased significantly, but the CEA, CA199, and CA125 levels began to increase progressively after a short decline. However, no solid tumor recurrence was observed in multiple reexaminations. It was not until 9 months after the elevation of tumor markers that multiple metastatic lesions appeared in the liver, which finally confirmed the diagnosis of metastatic SCNECP. After chemotherapy with etoposide 360 mg combined with carboplatin 200 mg, the tumor size was significantly reduced, and tumor markers decreased. However, the remission time was only 3 months. The patient's liver metastases continued to grow, and CEA, CA199, and CA125 levels continued to increase.

Conclusion

During CPAC treatment, PSA levels continued to decrease, whereas CEA, CA199, and CA125 levels continued to increase. This suggests the possibility of the transformation of CPAC into SCNECP.

The Application and Pitfalls of Immunohistochemical Markers in Challenging Diagnosis of Genitourinary Pathology

CONTEXT.—

The morphologic features of different entities in genitourinary pathology overlap, presenting a diagnostic challenge, especially when diagnostic materials are limited. Immunohistochemical markers are valuable when morphologic features alone are insufficient for definitive diagnosis. The World Health Organization classification of urinary and male genital tumors has been updated for 2022. An updated review of immunohistochemical markers for newly classified genitourinary neoplasms and their differential diagnosis is needed.

OBJECTIVE.—

To review immunohistochemical markers used in the diagnosis of genitourinary lesions in the kidney, bladder, prostate, and testis. We particularly emphasized difficult differential diagnosis and pitfalls in immunohistochemistry application and interpretation. New markers and new entities in the 2022 World Health Organization classifications of genitourinary tumors are reviewed. Recommended staining panels for commonly encountered difficult differential diagnoses and potential pitfalls are discussed.

DATA SOURCES.—

Review of current literature and our own experience.

CONCLUSIONS.—

Immunohistochemistry is a valuable tool in the diagnosis of problematic lesions of the genitourinary tract. However, the immunostains must be carefully interpreted in the context of morphologic findings with a thorough knowledge of pitfalls and limitations.