Urachal Signet Ring Cell Carcinoma: A Clinicopathological Analysis of 28 Cases

TL;DR

This study finds that urachal signet ring cell bladder cancer is rare, aggressive, and has worse survival outcomes compared to other types of urachal cancer.

Contribution

The study identifies urachal signet ring cell carcinoma as a distinct subtype with a strong independent poor prognosis.

Findings

Signet ring cell subtype is associated with advanced disease at diagnosis and higher recurrence rates.

Patients with signet ring cell carcinoma had lower five-year cancer-specific survival rates.

Adjuvant chemotherapy was more frequently used in signet ring cell cases despite worse outcomes.

Abstract

Urachal carcinoma of the bladder is a rare malignancy that develops from urachal remnants. The signet ring cell subtype is a particularly rare and aggressive subtype that often presents a diagnostic challenge. This study analyzed a multi-institutional cohort of 75 patients, comparing 28 cases of urachal signet ring cell carcinomas with 47 cases of different urachal carcinomas subtypes. Our results show that the signet ring cell subtype is associated with advanced disease at diagnosis and a higher recurrence rate compared to the control group. Despite aggressive surgical management and chemotherapy, patients with this subtype had lower survival rates. Overall, the presence of signet ring cells is a strong independent predictor of poor prognosis. These results highlight the importance of implementing dedicated clinical strategies and therapeutic interventions targeted to this specific histological profile.

Background: Urachal carcinoma is a rare malignancy comprising less than 1% of all bladder cancers. The signet-ring cell subtype is particularly aggressive and poses significant diagnostic and therapeutic challenges. Methods: A retrospective review of urachal carcinoma cases from 1989 to 2023 was conducted using data from BC Cancer and MD Anderson Cancer Center. The study analyzed 75 patients, including 28 signet-ring cell carcinoma (SRCC) cases and a control group of 47 non-SRCC cases, to compare survival patterns, treatment outcomes, and histopathological features. Results: Clinically, the SRCC subtype was associated with advanced stage at presentation (pT3/pT4) and a higher recurrence rate (82% vs. 53%; p = 0.01). Survival analysis demonstrated worse outcomes for the SRCC cohort, with a five-year cancer-specific survival (CSS) of 39% compared to 64% in the non-signet group (p = 0.053). Partial cystectomy remained the primary surgical approach for both cohorts. Adjuvant chemotherapy was administered more often in SRCC cases (86% vs. 47%). Conclusions: By providing a comprehensive multi-institutional analysis, this study establishes urachal SRCC as a distinct clinical entity with a strong independent prognostic significance. Despite aggressive multimodal management, it carries a poorer prognosis compared to urachal non-SRCC, emphasizing the need for subtype-specific therapeutic guidelines.

Figures