Primary Adenosquamous Carcinoma of the Prostate: A Rare Aggressive Tumor

Case report: Adenosquamous carcinoma of the prostate with greater than 20 month response to multimodal therapy

“…Histologically, both glandular and keratinizing squamous patterns are present. Squamous components are often negative for PSA and PSAP immunostains; patients with large squamous fractions may have normal PSA 3 , 4 . The tumors are usually large, sometimes replacing a substantial portion of the prostate.…”

“…Prostate ASC is clinically aggressive 2 . Locally advanced disease may be common at relatively low PSA levels depending on the extent of the squamous component 4 . Therefore, preoperative counseling regarding the possibility of adjacent organ involvement and need for extensive resection should be considered even if disease appears to be clinically localized.…”

“…There is a paucity of data regarding systemic chemotherapy or immunotherapy. While no regimens are currently recommended, 4 a recent case report demonstrated short-term response at 6 weeks to external beam radiation therapy (EBRT) and PD-1 inhibitor therapy in metastatic prostate ASC (Table 1).…”

Squamous cell carcinoma of the prostate with concomitant adenocarcinoma in the absence of prior androgen deprivation therapy

“…[4-6, 8, 9] Additionally, the squamous component can be differentiated by lack of staining with low molecular weight keratins, such as CAM 5.2 which will stain the glandular component. [6,9] Squamous cell carcinomas in the prostate have additionally been noted to stain positive with racemase/AMACR, but this is not helpful in determining the origin because cancers of urothelial origin also stain with AMACR. [5] Bassler [8] noted that in areas where adenocarcinoma and squamous components intermingled, the nuclei became larger and more pleomorphic like squamous carcinoma but maintained an immunohistochemical profile similar to adenocarcinoma.…”

“…[3] Prostate cancers with squamous differentiation frequently present with lower urinary tract symptoms, often without elevation of PSA. [9] Wang [2] suggests that squamous carcinomas, in contrast to adenocarcinomas, occur more often around the prostatic urethra as opposed to the peripheral zone. Therefore, most squamous carcinomas present with obstructive symptoms that are thus initially treated with transurethral resection of the prostate, which is how many of them are initially diagnosed.…”