# Renal-Type Clear Cell Carcinoma of the Prostate: A Histopathological Case Report of a Rare and Underrecognized Variant

## TL;DR

This case report describes a rare type of prostate cancer that resembles kidney cancer and highlights the need for careful diagnosis.

## Contribution

The paper presents a rare histopathological variant of prostate cancer not recognized by the WHO.

## Key findings

- A 73-year-old male was diagnosed with renal-type clear cell carcinoma of the prostate after biopsy and imaging.
- The tumor's morphology resembled renal cell carcinoma, requiring careful differential diagnosis.
- Immunohistochemistry confirmed the diagnosis after ruling out concurrent kidney cancer.

## Abstract

Background and Clinical Significance: Prostatic malignancies are amongst the leading malignancies in incidence. They represent a mixed group of conditions, predominantly characterized by adenocarcinomas, which are themselves predominantly acinar. Case Presentation: Herein, we present a morphological case report of a 73-year-old male who underwent transrectal ultrasound-guided needle biopsy due to elevated PSA levels (18.61 ng/mL). Histopathology of the biopsy specimen was represented by pleomorphic cells with predominantly clear cytoplasm, with relatively eccentric, pyknotically appearing nuclei with hyperchromatic chromatin and no visible nucleoli. After imaging excluded concomitant renal malignancy and confirmatory immunohistochemistry was carried out, the patient was diagnosed with renal-type clear cell carcinoma of the prostate. Conclusions: While unrecognized by the WHO due to its rarity, renal-type clear cell acinar adenocarcinoma of the prostate is a unique type of prostatic malignancy, which, due to its morphological appearance, necessitated careful differential diagnosis.