Small cell-like change in prostatic intraepithelial neoplasia, intraductal carcinoma, and invasive prostatic carcinoma: a study of 7 cases

Small cell-like change in prostatic adenocarcinoma and intraductallesions – neuroendocrine or not?

Background

Small cell-like change in prostatic neoplasia (both invasive adenocarcinoma and intraepithelial lesions) is described in three previous reports. None of them to date proved to be associated with overt prostate neuroendocrine carcinoma.

Case presentation

We report findings from a radical prostatectomy of 80-year-old patient (adenocarcinoma GG5 pT3b with 10% involvement of the gland) with small cell-like change in intraductal carcinoma and in the invasive component. An additional 3.5-mm focus of poorly differentiated carcinoma was observed (PSA, TTF1, chromogranin and CD56 negative; synaptophysin positive in scattered cells; and a Ki67 label index of 50%).

Conclusion

Our case expands the data accumulated on small cell-like change in prostate neoplasia. As most of other reported cases, there was no expression of neuroendocrine markers or high proliferative index in small-cell like areas. On the other hand, for the first time, a transition morphology between acinar adenocarcinoma and neuroendocrine carcinoma was observed in a prostate with small cell-like change.

Intraductal Carcinoma of the Prostate as a Cause of Prostate Cancer Metastasis: A Molecular Portrait

Simple Summary

Most men with prostate cancer will live as long as those who do not have prostate cancer. However, some men will die early of their disease due to a particular type of prostate cancer associated with recurrence and metastasis: intraductal carcinoma of the prostate. In this review, we discuss the associations between intraductal carcinoma of the prostate and metastasis, and the contemporary knowledge about the molecular alterations of intraductal carcinoma of the prostate.

Abstract

Intraductal carcinoma of the prostate (IDC-P) is one of the most aggressive types of prostate cancer (PCa). IDC-P is identified in approximately 20% of PCa patients and is associated with recurrence, metastasis, and PCa-specific death. The main feature of this histological variant is the colonization of benign glands by PCa cells. Although IDC-P is a well-recognized independent parameter for metastasis, mechanisms by which IDC-P cells can spread and colonize other tissues are not fully known. In this review, we discuss the molecular portraits of IDC-P determined by immunohistochemistry and genomic approaches and highlight the areas in which more research is needed.

Small Cell-like Change in Central Zone Histology-A New Observation Mimicking Cribriform Intraductal Prostatic Adenocarcinoma

A small cell-like change in prostate has been described in high-grade prostatic intraepithelial neoplasia (PIN), intraductal prostatic adenocarcinoma, and invasive prostate cancer. It occurs when these processes have a cribriform architecture. To date, small cell-like change has not been described in benign glands. Herein, I describe such a change in cribriform central zone histology from a radical prostatectomy with a spatially remote treatment naïve Grade Group 3 prostate cancer. The cancer did not have cribriform morphology or intraductal prostatic adenocarcinoma. The small cell-like change was positive for racemase in PIN-4 cocktail and no nuclei were highlighted by Ki-67. This is the first report of a small cell-like change in benign prostate tissue. Although rare, such finding in cribriform architecture of central zone histology can potentially be misinterpreted as a neoplastic process.

Neuroendocrine Differentiation of Prostate Cancer-An Intriguing Example of Tumor Evolution at Play

Our understanding of neuroendocrine prostate cancer (NEPC) has assumed a new perspective in light of the recent advances in research. Although classical NEPC is rarely seen in the clinic, focal neuroendocrine trans-differentiation of prostate adenocarcinoma occurs in about 30% of advanced prostate cancer (PCa) cases, and represents a therapeutic challenge. Even though our knowledge of the mechanisms that mediate neuroendocrine differentiation (NED) is still evolving, the role of androgen deprivation therapy (ADT) as a key driver of this phenomenon is increasingly becoming evident. In this review, we discuss the molecular, cellular, and therapeutic mediators of NED, and emphasize the role of the tumor microenvironment (TME) in orchestrating the phenotype. Understanding the role of the TME in mediating NED could provide us with valuable insights into the plasticity associated with the phenotype, and reveal potential therapeutic targets against this aggressive form of PCa.

Evolving concepts in prostatic neuroendocrine manifestations: from focal divergent differentiation to amphicrine carcinoma

Prostatic neuroendocrine manifestations encompass a heterogeneous spectrum of morphologic entities. In the era of evidence-based and precision-led treatment, distinction of biologically relevant clinical manifestations expanded the evolving clinical role of pathologists. Recent observations on the occurrence of hormone therapy-induced aggressive prostatic cancers with neuroendocrine features have triggered the need to refine the spectrum and nomenclature of prostatic neuroendocrine manifestations. Although the morphologic assessment still remains the basis of the diagnostic workup of prostatic neoplasms, the application of ancillary biomarkers is crucial in the accurate classification of such presentations. This review provides a diagnostic roadmap for the practicing pathologist by reviewing the characteristic morphologic, immunohistochemical, and molecular correlates of various faces of prostatic neuroendocrine manifestations.

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.