Acinar adenocarcinoma is a malignant tumor that develops from prostatic gland cells. It is a subtype of prostate cancer (PCa) and accounts for about 5% of all PCa. It is a very rare and aggressive subtype of PCa. Most of the time, acinar adenocarcinoma occurs in combination with prostate ductal adenocarcinoma. Prostate adenocarcinoma of acinar type usually grows more slowly than ductal adenocarcinoma and is associated with lower PSA levels, but the exact reason for this is not fully understood.
Most patients with acinar adenocarcinoma have nonspecific symptoms, such as frequent urge to urinate and pain during urination. Occasionally, the cancer may be accompanied by blood in the semen. The presence of a tumor is usually detected by routine prostate needle core biopsy done for elevated PSA.
The most common treatment for acinar adenocarcinoma of the prostate is radical prostatectomy (RP). However, this procedure can lead to side effects like urinary problems and erectile dysfunction. Another option is active surveillance, in which the patient is monitored closely by his doctor for any changes in PSA and other signs of cancer.
In some cases, a physician may recommend a more intensive form of therapy, such as a combination of radiation and drugs. However, this can be risky for the patient and is generally reserved only when the patient is healthy enough to tolerate it.
A rare but potentially serious side effect of acinar adenocarcinoma in the prostate is that it can spread to surrounding tissues. This is called extraprostatic extension (EPE) and occurs in about 6% of acinar adenocarcinomas. EPE is associated with a poorer prognosis than acinar adenocarcinoma.
Another potential side effect of acinar adenocarcinoma can be the obstruction of the bile duct (biliary stricture). This occurs in about 12 percent of acinar adenocarcinomas.
A man in his late 60s was diagnosed with Gleason score 3 + 3 = 6 acinar adenocarcinoma and classified as low risk based on biopsy. During RP, the operative specimen showed a large tumor mass with organ confined disease (stage pT2c) and extraprostatic extension involving the periprostatic soft tissue and nerves (Stage pT4N0M1c). A second lesion was found in a lateral horn of the prostate and had Gleason pattern 5 and 7 (Figure 1). This additional tumour focus was differentiated from the other one by its cuboidal and columnar cell morphology. This led to a change in the staging of the prostate cancer to pT4N0M1c, stage IVB according to AJCC 8th edition.
