Primary carcinoma of prostate with squamous cell features and includes pure squamous cell carcinoma (SCC) and adenosquamous carcinoma (ASC) or adenocarcinoma mixed with squamous cell carcinoma
Very rare, only ~55 cases SCC and ~30 cases ASC reported.
Diagnosis requires exclusion of secondary prostate SCC from other organs.
Both SCC and ASC can arise de novo or preceded by prior prostate adenocarcinoma with or without prior radiation or hormonal treatment.
Serum PSA or PSAP typically normal, even with advanced disease.
Generally poor response to surgical, hormonal, chemotherapeutic, or radiation therapies.
Pure SCC is similar to SCC of other anatomic sites (e.g. keratin formation, intercellular desmosomes, etc.) (image A) & (image B).
Well to poorly differentiated (Broder's grading).
Glandular component of ASC similar to acinar adenocarcinoma.
SCC is PSA- and PSAP- and HMWK+.
Glandular component of ASC is PSA+ and PAP+ and HMWK-.
Do not confuse this with squamous metaplasia adjacent to an infarct (much more common diagnosis).
Behave more aggressively than prostate adenocarcinoma.