According to the tumor registries, 29,783 cases of prostate cancer were evaluated at Mayo Clinic from January 15, 1970, until January 2, 2009. Among these, only 9 cases of SRCC of the prostate were identified (), for an incidence of 30 per 100,000 cases of prostate cancer. Details of these cases follow.
Characteristics of Patients With Signet Ring Featuresa,b
A 58-year-old man presented with lower urinary tract symptoms. Fourteen years before presentation, he had had a perianal abscess and a rectocutaneous fistula that ultimately required an abdominoperineal resection and that proved benign on pathologic analysis. At the time of presentation, he was found to have left ureteral obstruction and underwent open left nephrostomy tube placement and transurethral resection of the prostate (TURP). Pathology demonstrated a grade 4 adenocarcinoma with signet ring cell features. The patient underwent radiation
therapy, the exact dosage of which could not be determined from a review of the record, followed by multiple resections of the prostate. He never underwent a formal GI work-up. He died 2 years later of peritoneal carcinomatosis of a primary tumor of unknown origin. The patient was treated at an outside facility immediately before his death. Thus, the pathology and events surrounding his death are unclear.
Three years after undergoing TURP (with findings of benign tissue), an 82-year-old man presented to an outside facility with back pain, hip pain, and abnormal findings on a digital rectal examination. He underwent a biopsy of the prostate, which revealed grade 4 adenocarcinoma of the prostate with signet ring cell features. The patient subsequently underwent bilateral orchiectomy. He died 5 months later of hypotensive shock as a result of pneumonia.
A 68-year-old man from Mexico presented with abrupt onset of serious bone pain that aroused suspicion for metastatic prostate cancer. The patient underwent a biopsy and was found to have a grade 3 to 4, stage VI adenocarcinoma of the prostate with signet ring cell features. The patient was initially treated with a dose of intramuscular luprolide and, after presenting to our institution, underwent a bilateral orchiectomy. One year later, the patient underwent palliative radiation therapy for osseous metastasis causing substantial pain. The patient died soon after radiation, within 11 months of diagnosis.
Eleven months after undergoing TURP (with findings of benign tissue), a 65-year-old man presented with recurrent obstructive symptoms. The patient underwent a second TURP and was found to have a grade 3 adenocarcinoma of the prostate with signet ring cell features. A bone scan demonstrated bony metastasis. The patient underwent bilateral orchiectomy and began taking stilbestrol. The patient died at an outside institution 2 years later from complications arising from metastatic SRCC of the prostate.
A 67-year-old man underwent a retropubic radical prostatectomy in 1988 at an outside institution. Pathology demonstrated a grade 3 of 4, a Gleason 3+5=8, N0, M0, stage C adenocarcinoma of the prostate with signet ring cell features. The patient developed a PSA recurrence and was treated initially with leuprolide. Two years later, he had a PSA failure on androgen blockade and was referred to our institution. The patient underwent contrast-enhanced computed tomography, the results of which were normal. There was no record of a colonoscopy, and a bone scan at the time of consultation (4 years after prostatectomy) was positive for distant metastases. The patient continued taking leuprolide and remained asymptomatic at his last follow-up in 1993. The patient died 9 years after his initial diagnosis of unknown causes.
A 67-year-old man who was being evaluated for a recurrent polyp in the hepatic flexure had abnormal findings on digital rectal examination. Biopsy of the prostate was performed, and pathology showed a Gleason 4+5=9 adenocarcinoma of the prostate with signet ring cell features involving 25% of the cores. The patient's pretreatment PSA level was 1.9 ng/mL (to convert to μg/L, multiply by 1). Other than the colonic polyp, no other evidence of malignancy was found on computed tomography, bone scans, and multiple colonoscopies. The patient elected to undergo hormone therapy while he underwent a right hemicolectomy for the polyp, which was found to be a tubular adenoma with high-grade dysplasia. The patient underwent external-beam radiation for a total dose of 7600 Gy in 38 fractions. After completing his radiation, he stopped his hormonal therapy. To date, he has no detectable PSA level.
A 79-year-old man presented with a 3-year history of intermittent gross hematuria. Cystoscopy revealed a 1.5-cm mass in his prostatic urethra. On biopsy, a grade 4/4 invasive adenocarcinoma of the prostate with signet ring cell features was discovered near the bladder neck. The patient's PSA level at the time of diagnosis was 5.9 ng/mL. The patient underwent a full work-up, including a colonoscopy with biopsy specimens negative for neoplasia. He then underwent cystoprostatectomy with ileal conduit secondary to the lesion location. Final pathologic diagnosis was T3bN1M0. The tumor was positive for cytokeratin 7 and 20 and for homeobox protein CDX2 but negative for PSA, making a prostatic origin less likely. However, because of the negative GI work-up and the presence of prostate cancer cells of normal appearance in addition to the signet ring cells, we elected to evaluate this patient in our series. The patient died within 4 months of complications from urosepsis.
A 51-year-old man presented with a history of a robotassisted radical prostatectomy (RARP) performed at an outside facility. He was found to have a Gleason 3+5=8, T3bN0MX adenocarcinoma with signet ring cell features and positive margins. The patient underwent a complete evaluation at the outside facility, including imaging and colonoscopy. However, only computed tomographic and bone scan findings were reviewed at our institution, which were negative for evidence of metastasis or for a primary tumor of a different origin. The patient underwent external-beam radiation therapy at an outside institution (dose unspecified) and is currently alive with no evidence of malignancy.
A 59-year-old man presented with an elevated PSA level of 4.8 ng/mL. He underwent a transrectal needle biopsy demonstrating a Gleason 4+4=8 adenocarcinoma with signet ring cell features (). A thorough GI work-up was performed; cystoscopy ruled out metastasis or a primary tumor of a different origin. Physical examination demonstrated an enlarged gland, with minimal induration on the left. The patient underwent a RARP with bilateral pelvic lymphadenectomy. Final pathologic stage was Gleason 4+4=8, T2bN0M0 with signet ring cell features. The patient began receiving adjuvant hormonal therapy and will continue this therapy for 2 years.
Signet ring cells seen on biopsy specimen (patient 9).
Twenty articles were identified in the English-language literature and are summarized in . In total, 42 patients with SRCC of the prostate were included in the review. Our experience added an additional 9 patients. A summary of the characteristics of all 51 patients is presented in . The PSA level varied widely, from 1.9 to 536 ng/mL. More patients (33%) presented with stage 4 cancer than with any other stage of cancer. The most common Gleason sum was 8 (33%), and a combination of surgery, radiation, and hormonal therapy was most often used (41%), followed closely by hormonal therapy alone (31%).
Summary of Cases from 20 Referencesa
Characteristics of 51 Patients With Primary Signet Ring Cell Carcinoma of the Prostatea,b
The minority of patients 31% (16/51) had a documented GI work-up to determine the primary SRCC source. For pathologic diagnosis, the most common stains performed were the periodic acid–Schiff stain, performed in 70% of patients; the prostate-specific acid phosphatase (PSAP) stain, performed in 70% of patients; and the Alcian blue stain, performed in 62% of patients. These were positive in 50% (18/36), 87% (34/39), and 44% (14/32) of cases, respectively. Carcinoembryonic antigen (39%) and mucicarmine (39%) were less commonly used and were positive in 20% (4/20) and 40% (8/20) of patients, respectively. The extent of signet ring cell involvement of the specimen was reported in 76% (39/51) of cases. Of these, 84% (33/39) documented more than 20% of the tumor-containing signet ring cells.
The mean overall survival was 28 months in the compiled group. Evaluating treatment-specific survival, the highest survival (mean, 45 months) was seen in the group receiving a combination of surgical and hormonal therapy, followed by the radiation and hormonal therapy group (mean, 37 months). The shortest survival was seen after surgical therapy alone, which reflected one patient who died of sepsis unrelated to his cancer 4 months after surgery.