Case Report: Prostate Adenocarcinoma With Mucinous Features of Normal-Level Serum PSA, Atypical Imaging, Biopsy-Negative, and Peculiar Urethrocystoscopic Manifestation

Prostate Adenocarcinoma with Signet-Ring Cells and Features of Mucin: A Clinical Case and Literature Review

Introduction: Signet-ring cells are typically associated with mucin-secreting epithelium; thus, they are most commonly found in the gastrointestinal tract, but not exclusively. Primary signet-ring cell carcinoma of the prostate is a rare and poorly differentiated, aggressive acinar adenocarcinoma variant with a grim prognosis. Clinical Case: In June of 2023, a 54-year-old Caucasian male presented with a complaint of lower urinary tract obstructive symptoms with occasional macrohematuria, non-specific body aches, and shortness of breath. A prostate specimen obtained in transurethral resection of the prostate was sent for histopathological examination. After a series of extraprostatic diagnostic workups, including fibrogastroduodenoscopy, colonoscopy computed tomography imaging, and immunohistochemical studies, the patient was diagnosed with primary prostatic signet-ring cell adenocarcinoma stage IV. Unfortunately, due to the advanced stage of the disease, PE, and third-degree thrombocytopenia, the patient was not a candidate for chemotherapy and died of cardiopulmonary insufficiency later that week. Discussion: Prostatic signet-ring cell carcinoma accounts for 0.02% of all prostate adenocarcinoma cases. Due to its nature and epidemiology, a diligent extraprostatic investigation has to be carried out. The disease often presents with unremarkable clinical symptoms and variable serum prostate-specific antigen results, which may contribute to its late diagnosis. Inconsistent immunohistochemical findings and an unpredictable response to hormonal treatment together pose both diagnostic and therapeutic challenges that negatively affect the prognosis. Conclusions: This study highlights the importance of a multidisciplinary approach and the need for diagnostic and therapeutic consensus within the research community in search of the primary site of the disease, which may positively influence the prognosis.

Primary renal mucinous adenocarcinoma masquerading as a giant renal cyst: a case report

Mucinous adenocarcinoma of the kidney is rarely reported in the literature. We present a previously unreported mucinous adenocarcinoma arising from the renal parenchyma. A 55-year-old male patient with no complaints showed a large cystic hypodense lesion in the upper left kidney on contrast-enhanced computed tomography (CT) scan. A left renal cyst was initially considered, and a partial nephrectomy (PN) was performed. During the operation, a large amount of jelly-like mucus and bean-curd-like necrotic tissue was found in the focus. The pathological diagnosis was mucinous adenocarcinoma, and further systemic examination revealed no clinical evidence of primary disease elsewhere. Then the patient underwent left radical nephrectomy (RN), and the cystic lesion was found in the renal parenchyma, while neither the collecting system nor the ureters were involved. Postoperative sequential chemotherapy and radiotherapy were administered, and no signs of disease recurrence were observed over 30 months of follow-up. Based on a literature review, we summarize the lesion with rarity and the associated dilemma in preoperative diagnosis and treatment. Given the high degree of malignancy, a careful history analysis accompanied by dynamic observation of imaging and tumor markers is recommended for the diagnosis of the disease. Comprehensive treatment based on surgery may improve its clinical outcomes.