Prostate squamous cell carcinoma developing 11 years after external radiotherapy for prostate adenocarcinoma

INTRODUCTION: Secondary bladder, colon, and rectal cancers are relatively common after prostate radiotherapy. However, secondary squamous cell carcinoma of the prostate is rare. CASE PRESENTATION: An 85‐year‐old man presented with dysuria and low‐serum prostate‐specific antigen levels. His medical history included localized prostate adenocarcinoma (Gleason score of 4 + 5) treated with combined three‐dimensional conformal radiotherapy and androgen deprivation therapy, 11 years ago. Urethroscopy and magnetic resonance imaging showed a bulging mass around the prostatic urethra. Transurethral resection of the prostate performed for histopathological diagnosis revealed squamous cell carcinoma. CONCLUSION: Hereby, a rare case of secondary squamous cell carcinoma of the prostate after radiotherapy for adenocarcinoma was reported, which was found after 11 years of radiotherapy with symptom of dysuria including urinary hesitancy, difficulty, pain during urination, and low‐serum prostate‐specific antigen levels.