Secondary signet-ring cell tumour of the prostate derived from a primary gastric malignancy

FDG PET/CT in Prostate Metastasis From Gastric Cancer

ABSTRACT

Prostate metastasis from gastric cancer is rare. We report MRI and FDG PET/CT findings in a case with prostate metastasis from gastric cancer. In this case, the prostate metastasis was the first manifestation of the gastric cancer. This case demonstrates the usefulness of FDG PET/CT in identifying the primary gastric cancer and its contribution for an accurate staging. Familiarity with the FDG PET/CT findings of the prostate metastasis may be useful for the differential diagnosis of the hypermetabolic prostate lesions.

Mucinous and secondary tumors of the prostate

Primary mucinous tumors and secondary tumors involving the prostate gland are relatively uncommon, however they have important diagnostic, therapeutic, and prognostic implications. The primary mucinous tumors of the prostate include mucinous (colloid) adenocarcinoma of the prostate, prostatic adenocarcinoma with mucinous features, and mucinous adenocarcinoma of the prostatic urethra (mucin-producing urothelial-type adenocarcinoma of the prostate). Mucinous adenocarcinoma of the prostate is defined as a primary prostatic acinar tumor characterized by the presence of at least 25% of the tumor composed of glands with extraluminal mucin. This diagnosis can only be made in radical prostatectomy specimens. Recent studies have shown that these tumors have a similar or in some cases better prognosis than conventional prostatic adenocarcinoma treated by radical prostatectomy. The preferred terminology for tumors that are composed of <25% extraluminal mucinous component in radical prostatectomy specimens is 'prostatic adenocarcinoma with mucinous features.' All cases of prostatic adenocarcinoma with extraluminal mucinous components in prostate needle core biopsies or transurethral resection of the prostate specimens are also referred to as 'prostatic adenocarcinoma with mucinous features.' Mucinous adenocarcinoma of the prostatic urethra (mucin-producing urothelial-type adenocarcinoma of the prostate) as the name implies, does not arise from prostatic acini or ducts, and is a distinct entity that arises from the prostatic urethra usually from urethritis glandularis or glandular metaplasia with malignant transformation, and is analogous to adenocarcinoma with mucinous differentiation arising from the urinary bladder. This tumor is aggressive and has a relatively poor prognosis. The most common secondary tumors that arise from adjacent organs and spread (direct extension or metastasis) to the prostate gland, include urothelial carcinoma of the bladder and colorectal adenocarcinoma. Other secondary tumors that may involve the prostate include metastatic epithelial tumors from several other sites, malignant melanoma and soft tissue tumors.

Rediscovering Secondary Tumors of the Prostate in the Molecular Era

Metastatic involvement of the prostate from noncontiguous solid tumors is a rare event occurring by means of vascular dissemination. The reported cases of biopsy and surgical samples with metastatic involvement have increased; however, a comprehensive understanding of secondary tumors of the prostate is currently missing. Metastases to the prostate carry a dismal prognosis and may pose serious diagnostic challenges to both clinicians and pathologists, with crucial therapeutic implications. Secondary tumors of the prostate spread more frequently from the digestive tract, the lung, and the kidney. The integration of clinicoradiologic data with appropriate pathologic and immunohistochemical analyses is essential for the identification and the characterization of secondary tumors of the prostate, whereas molecular analyses could provide additional and complementary information, enabling precise diagnosis and appropriate clinical management. Patients with solitary metastases could benefit from prostatic resection and adjuvant therapy, whereas in cases of disseminated diseases, symptom control may be obtained with palliative procedures. The purpose of this review was to assess the current state of knowledge of secondary tumors involving the prostate gland and to discuss short-term future perspectives, while providing a practical approach to these uncommon conditions for pathologists and oncologists.

Gastric adenocarcinoma: prostatic metastasis

Secondary prostatic neoplasms are usually the result of direct invasion by neighboring organs or infiltration from hematological malignancies. Gastric adenocarcinoma metastasizing in the prostate is extremely rare and to our knowledge only seven cases have been documented in the literature. We report another case of a patient who underwent transurethral resection of the prostate for bladder outflow obstruction which incidentally revealed an occult metastatic adenocarcinoma from an undiagnosed gastric cancer.

Metastatic signet ring cell adenocarcinoma of the bladder: responsive to treatment?

Signet ring cell variant of mucinous adenocarcinoma of the urinary bladder is an exceptionally rare urologic malignancy, generally felt to be resistant to chemotherapy and radiotherapy. We describe a case of this malignancy with unusual sites of metastasis and an unexpectedly good response to treatment.

Case report: gastric adenocarcinoma metastatic to the prostate gland

Metastasis to the prostate gland from gastric cancer is exceedingly rare. We have presented a rare case of gastric malignancy metastasizing to the prostate diagnosed by transrectal ultrasound guided prostate biopsy.