Urachal Carcinomas of the Nonglandular type: Salient Features and Considerations in Pathologic Diagnosis

Urachal mixed adenocarcinoma and small cell neuroendocrine carcinoma with widespread metastasis and resistance to chemotherapy: a case report

Neuroendocrine carcinoma arising from the urachus is extremely rare. We describe a case of a 33-year-old gentleman who presented with hematuria and diagnosed to have a composite adenocarcinoma and small cell neuroendocrine carcinoma arising from the urachus. The patient also had widespread metastasis at the time of presentation, therefore, he was referred for chemotherapy. However, the disease showed progression despite treatment. Recognition of neuroendocrine carcinoma component in urachal tumors, although rare, is very essential as this histologic type carries poor prognosis with aggressive clinical outcome.

[Rare tumors and tumor types of the urinary system in the 5th edition of the WHO classification 2022]

The 5th edition of the World Health Organization (WHO) classification of tumors of the urinary tract and male genital organs introduced both general and specific changes in structure, classification, and nomenclature. This also applies to rarer tumors and tumor subtypes of the urinary system. Knowledge of these changes is relevant for routine histopathological work. This article provides an overview of the main new features of the rarer tumors and tumor subtypes of the urinary system in the new edition of the WHO classification.

Glandular Lesions of the Urinary Bladder: Diagnostic and Molecular Updates

Glandular lesions in the urinary tract or their associated pathologies can pose a diagnostic challenge. There is a variety of benign alterations and tumor types that need to be taken into account in differential diagnostic considerations. In recent times, efforts for better defining these alterations or lesions both on the histopathological and molecular levels have been undertaken. This article will provide an update on current diagnostic and molecular considerations of these lesions.

Urachal carcinoma: The journey so far and the road ahead

Urachal carcinoma, a rare cancer arising from urachus, accounts for about 1% of bladder cancer. The diagnosis at stage I shows about 63% 5-year survival whereas only 8% of the patients at stage IV shows a 5-year survival. Above 90% of urachal carcinomas are adenocarcinomas and most of the urachal carcinoma cases are invasive, showing a high resemblance to adenocarcinoma of various origins, making it hard for a conclusive diagnosis. Even though inconclusive, immunohistochemistry can play a significant role in identifying urachal carcinoma. Most cases show the biomarkers CK20 and CDX2, whereas CK7 and β-catenin are expressed at a lesser frequency. Due to the few cases available, there is a lack of evidence regarding specific markers differentiating urachal carcinoma from colorectal or primary bladder adenocarcinomas. In addition to immunohistochemistry, genomic characterization is emerging to play a role in the classification and treatment of the disease. Urachal carcinoma has been reported to have a molecular level similarity with colorectal malignancies regarding certain gene expressions. The TP53 mutations inactivating the tumor suppressor can probably be explored as a possible target in treating urachal carcinoma. Additionally, certain targets identified in gastric and breast cancer along with anti-HER2 treatment strategies can be explored. Immuno-oncology utilizes immune checkpoint inhibitors for the treatment of MSI-H tumors whereas a combination of tyrosine kinase inhibitors along with immune checkpoint inhibitors are being studied to treat MSI stable tumors. The article is an in-depth overview of urachal carcinoma addressing the current landscape with an emphasis on the future scenario.

Urachal Carcinoma, An Unusual Possibility of Hematuria; Case Report and Literature Review

Urachal cancer is very rare, accounting for only 0.5–2% of bladder-associated malignancies and 0.01% of all cancers in adults. It has an insidious appearance, an aggressive behavior and a poor prognosis. The most common symptoms are hematuria and the presence of a palpable hypogastric mass. The scarcity of cases and the low number of studies carried out explains the lack of an evidence-based management strategy, but it seems that surgical treatment (open, laparoscopy or robot-assisted) represents the gold standard, while neoadjuvant and adjuvant chemotherapy or radiotherapy has a limited impact on overall survival. Since mucinous cystadenocarcinoma of urachal origin is a very uncommon pathological condition the differential diagnosis may be difficult and pathological investigations have to elucidate this disorder. It is worth mentioning the psychological impact on the patient in addition to the medical aspects. A rare condition is associated with heightened risk for mental health and psychosocial difficulties and this must be taken into account in the subsequent follow-up of the patient. In order to increase awareness of this rare entity we report a case of a 40-year-old male with a urachal adenocarcinoma who was treated surgically, with a favorable outcome. We also perform a brief literature review about this type of tumor.

Clinical outcomes and patterns of population-based management of urachal carcinoma of the bladder: An analysis of the National Cancer Database

BACKGROUND

Given the low incidence of urachal carcinoma of the bladder (UCB), there is limited published data from contemporary population-based cohorts. This study aimed to describe demographic, clinicopathological features, and survival outcomes of patients diagnosed with UCB.

METHODS

The National Cancer Database (2004-2016) was queried for UCB patients. Descriptive analyses characterized demographics and clinicopathologic features. We assessed 5-year overall survival (OS) rates of the entire cohort and subgroups of localized/locally advanced and metastatic disease. We utilized Cox proportional hazards models to assess the association between covariates of interest and all-cause mortality and to examine the impact of surgical technique and chemotherapy.

RESULTS

We identified 841 patients with UCB. The most common histologic subtype was non-mucinous adenocarcinoma (39.6%). Approximately 50% had ≥cT2 disease, and 14.3% were metastatic at diagnosis. Altogether, partial cystectomy (60%) was most performed, and lymph node dissection was performed in 377 patients (44.8%), with specific temporal increase in utilization over the study period (p < 0.001). Overall, median OS was 59 months, and 5-year OS was 49%. In patients with localized/locally advanced disease, we found no association between partial and radical cystectomy (Hazards ratio [HR] 1.75; 95% CI 0.72-4.3) as well as receipt of perioperative chemotherapy (HR 1.97, 95% CI 0.79-4.90) and outcomes. Lastly, receipt of systemic therapy was not associated with survival benefit (HR 0.785, 95% CI 0.37-1.65) in metastatic disease cohort.

CONCLUSION

This large population-based cohort provides insight into the surgical management and systemic therapy, without clear evidence on the association of chemotherapy and survival in the perioperative and metastatic setting.

Clinical and Radiological Features of Urachal Carcinoma and Infection

PURPOSE

To explore the clinical and radiological differences between urachal carcinoma and urachal infection.

METHODS

Clinical and imaging information for 13 cases of urachal carcinoma and 14 cases of urachal infection confirmed by pathology were retrospectively analyzed. The size, location, shape, margin, lesion composition, calcification, T1 and T2 signal intensity, peripheral lymph nodes, degree of enhancement, adjacent bladder wall, and apparent diffusion coefficient (ADC) value were examined in both groups, and distinguish features were determined. The student t-test or Mann-Whitney U test was used for quantitative data, and Fisher's exact test was used for qualitative data. Kappa coefficient consistency test was used to evaluate the interobserver agreement.

RESULTS

Sex, hematuria, abdominal pain, calcification, and thickening of adjacent bladder wall can distinguish between urachal carcinoma and urachal infection (p < 0.05). There were no statistical differences in age (p = 0.076), size (p = 0.797), location (p = 0.440), shape (p = 0.449), margin (p = 0.449), lesion composition (p = 0.459), T1 signal intensity (p = 0.196), T2 signal intensity (p = 0.555), peripheral lymph nodes (p = 0.236), degree of enhancements (p = 0.184) and ADC value (p = 0.780) between two groups.

CONCLUSION

The following clinical and imaging features help distinguish urachal carcinoma from urachal infection: sex, hematuria, abdominal pain, calcification, and thickening of the adjacent bladder wall.

Clinical, Pathological, and Prognostic Analysis of Urachal Carcinoma

OBJECTIVE

The aim of this study was to improve understanding the clinical, pathologic, and prognostic features of urachal carcinoma (UrC), a retrospectively descriptive study was done in 2 clinical centers.

METHODS

After excluding the 2 missed patients, the clinical and pathological data of 59 patients with UrC, who were diagnosed or treated at 2 clinical centers between 1986 and 2019, was retrospectively analyzed. SPSS 22.0 (IBM) and GraphPad Prism 8.0.1 were used for statistics and data visualization. Survival data were analyzed by the Kaplan-Meier method and Log-rank tests. Cox proportional hazards regression were performed for find risk factors on predicting the prognosis.

RESULTS

Of all 59 patients, 47 were male and 12 were female. The median age at diagnosis was 51.6 years (range: 22-84 years). Gross hematuria was the most common symptom (79.66%). The majority of urachal neoplasms were adenocarcinomas (94.92%). Forty-two patients (72.41%) underwent extended partial cystectomy with en bloc resection of the entire urachus. The mean follow-up was 52 months (3-277 months). Median overall survival was 52.8 months (4-93 months). The 3-year cancer-specific survival (CSS) rate and 5-year CSS rate were 69.1% and 61.2%. There was no significant difference among localized T stage, tumor histologic grade and surgical procedures in determining prognosis by survival analyze. While patients with high-risk TNM stage (local abdominal metastasis, lymph node metastasis, or distant metastasis) (p = 0.003) and positive surgical margin (p < 0.001) had significantly worse prognosis.

CONCLUSIONS

The results indicate that high-risk TNM stage and positive surgical margin are risk predictors of prognosis. Localized T stage, histologic grade, and surgical procedure cause no significant effect on patient prognosis. The extended partial cystectomy is the recommended surgical approach for patients with UrC. Active multimodal treatments may improve the survival of patients with recurrent and metastatic disease.

Clinicopathological features of malignant urachal tumor: A hospital-based cancer registry data in Japan

OBJECTIVES

To identify the clinicopathological features of malignant urachal tumor in Japan, and analyze the 5-year overall survival of malignant urachal tumor patients.

METHODS

We used the hospital-based cancer registry data to extract malignant urachal tumor cases that were diagnosed in 2008-2009 and 2012-2015, histologically confirmed, and received the first course of treatment. We analyzed the 5-year overall survival using the 2008-2009 cohort's data.

RESULTS

We identified 456 patients, and malignant urachal tumor accounted for 0.4% of all malignant bladder cancers. The median age was 61 years (range 2-97), and 66% were men. The most common histology was adenocarcinoma (80%), followed by urothelial carcinoma (11%) and squamous cell carcinoma (3%). The proportions of patients were: 19% Ta/Tis/T1N0M0, 55% T2-3N0M0, 13% T4/N+ and 13% M+. Regarding the initial treatment, the proportions of surgery alone were 79% and 33% in cases of T3 or less N0M0 and T4/N+, respectively. The proportion of combination therapy including surgery and chemotherapy were 13% and 44% in T2-3N0M0 and T4/N+, respectively. Radiation therapy was not common at any stage. In the 2008-2009 cohort, the 5-year overall survival rate in Ta/Tis/T1N0M0, T2-3N0M0, T4/N+ and M+ were 60%, 64%, 63% and 12%, respectively.

CONCLUSIONS

Malignant urachal tumors are quite rare in Japan, and most of those without metastasis are likely to be treated by surgery alone, even at advanced stages. A standard of care must be established for malignant urachal tumor patients at advanced stages or with metastasis, as the prognosis of these patients can be poor.

[Urachal Cancer: an update of current molecular findings]

BACKGROUND

Urachal cancer is a rare type of cancer, often following a clinically aggressive course. Due to its rarity, knowledge about its molecular background is still limited. In addition, no sufficiently reliable diagnostic markers are available.

OBJECTIVES

The aim of the present study is to give an overview of our recent molecular projects on urachal cancer and to connect it with current literature in the field.

MATERIALS AND METHODS

Three projects are introduced. The first project identified and validated diagnostic biomarkers in urachal adenocarcinomas compared to colorectal adenocarcinomas and primary adenocarcinomas of the bladder using various proteomic methods. In the second project, the most relevant differential diagnostic markers between urachal adenocarcinomas and colorectal adenocarcinomas compared to normal tissue (urachal remnants) were determined by analyzing a miRNA panel. Sequence analyses were performed in the third project. The focus was on molecular differences to colorectal adenocarcinomas and urothelial carcinomas.

RESULTS AND CONCLUSIONS

We detected potential biomarker candidates for the immunohistochemical differential-diagnosis and generated a miRNA-based diagnostic scoring system with a potentially high differential-diagnostic significance. The sequence analyses data confirm the molecular autonomy of the urachal adenocarcinomas compared to other entities.

Urachal cancer-current concepts of a rare cancer

Urachal cancer is a rare but aggressive disease. In addition to the non-glandular tumors, non-cystic urachal adenocarcinomas are nowadays distinguished from the primary cystic variant. (Immunohistochemical) markers are only of minor differential diagnostic value and, therefore, the diagnosis is primarily established in a multidisciplinary approach. The non-cystic variant accounts for the majority of cases (83%), is more common in men (63%), shows a median age at diagnosis of 51 years and has a 5-year survival rate of about 50%. In organ-confined disease, usually a partial cystectomy of the tumor in the bladder dome, including the median umbilical ligament and umbilicus, is performed. In advanced stages, systemic therapy is needed while 5‑fuorouracil (5-FU) containing regimes have been shown to be more effective. Due to the rarity of the tumor, targeted therapy approaches based on a biological rationale are becoming increasingly relevant. As molecular data are still sparse, we compiled and analyzed the largest urachal cancer cohort to date. In 31% of the cases, MAPK-/PI3K signaling pathway alterations were detected (especially in K-/NRAS) with implications for anti-EGFR therapy approaches. Further potentially therapeutic alterations were detected in FGFR1, MET, PDGFRA, and erbB2/HER2. Additionally, PD-L1 tumor cell expression (clone: 22C3) was demonstrated in 16% of cases, therefore making anti-PD-1/PD-L1 immuno-oncological approaches worth considering despite the absence of mismatch repair deficiency (MMR-d) and/or high microsatellite instability (MSI-h). Finally, urachal adenocarcinomas seem to be a distinct entity on the molecular level with closer resemblance to colorectal adenocarcinomas than to urothelial carcinomas.

Urachal Mucinous Cystic Tumor of Low Malignant Potential with Concurrent Sigmoid Colon Adenocarcinoma

Urachal mucinous tumors are rare neoplasms with behaviour that can range from relatively benign to malignancy that can spread distantly or throughout the peritoneum as pseudomyxoma peritonei or peritoneal carcinomatosis. Here we describe a unique case of urachal mucinous cystic tumor of low malignant potential confined to an intact cyst at the dome of the urinary bladder, without rupture or peritoneal spread. The urachal mucinous tumor was an incidental finding on a staging CT scan performed for sigmoid colon adenocarcinoma. We believe that this case illustrates a potential diagnostic pitfall which could have prognostic and therapeutic implications. Due to the intestinal phenotype of these neoplasms, a urachal tumor of low malignant potential could be mistaken for metastatic spread from a colonic adenocarcinoma in the rare situation such as this case, where the two neoplasms occur concurrently.

[Urachal cancer - current concepts of a rare cancer (German version)]

Urachal cancer is a rare but aggressive disease. In addition to the non-glandular tumors, non-cystic urachal adenocarcinomas are nowadays distinguished from the primary cystic variant. (Immunohistochemical) markers are only of minor differential diagnostic value and, therefore, the diagnosis is primarily established in a multidisciplinary approach. The non-cystic variant accounts for the majority of cases (83%), is more common in men (63%), shows a median age at diagnosis of 51 years and has a 5-year survival rate of about 50%. In organ-confined disease, usually a partial cystectomy of the tumor in the bladder dome, including the median umbilical ligament and umbilicus, is performed. In advanced stages, systemic therapy is needed while 5‑fuorouracil (5-FU) containing regimes have been shown to be more effective. Due to the rarity of the tumor, targeted therapy approaches based on a biological rationale are becoming increasingly relevant. As molecular data are still sparse, we compiled and analyzed the largest urachal cancer cohort to date. In 31% of the cases, MAPK-/PI3K signaling pathway alterations were detected (especially in K-/NRAS) with implications for anti-EGFR therapy approaches. Further potentially therapeutic alterations were detected in FGFR1, MET, PDGFRA, and erbB2/HER2. Additionally, PD-L1 tumor cell expression (clone: 22C3) was demonstrated in 16% of cases, therefore making anti-PD-1/PD-L1 immuno-oncological approaches worth considering despite the absence of mismatch repair deficiency (MMR-d) and/or high microsatellite instability (MSI-h). Finally, urachal adenocarcinomas seem to be a distinct entity on the molecular level with closer resemblance to colorectal adenocarcinomas than to urothelial carcinomas.

Mucinous Cystadenoma of the Urachus and Review of Current Classification of Urachal Mucinous Cystic Neoplasms

Urachal neoplasms are uncommon and represent a minor portion of bladder tumors. According to the recently updated World Health Organization classification (2016), these tumors are classified as adenomas, adenocarcinomas, nonglandular neoplasms, and mixed carcinomas. The mucinous cystic neoplasms represent a small percentage of urachal tumors with morphologic spectrum ranging from benign mucinous cystadenoma to borderline mucinous cystic tumor of low malignant potential and to malignant mucinous cystadenocarcinoma. Benign urachal mucinous cystic adenomas are exceedingly rare, and only a few cases have been reported in the literature to date. The goal of this review is to summarize the clinical features, histopathologic characteristics, treatment, and prognosis of urachal mucinous cystadenoma in light of differentiating them from mucinous cystic tumor of low malignant potential and mucinous cystadenocarcinoma.

Biomarkers in Urachal Cancer and Adenocarcinomas in the Bladder: A Comprehensive Review Supplemented by Own Data

Urachal cancer (UrC) is a rare but aggressive cancer. Due to overlapping histomorphology, discrimination of urachal from primary bladder adenocarcinomas (PBAC) and adenocarcinomas secondarily involving the bladder (particularly colorectal adenocarcinomas, CRC) can be challenging. Therefore, we aimed to give an overview of helpful (immunohistochemical) biomarkers and clinicopathological factors in addition to survival analyses and included institutional data from 12 urachal adenocarcinomas. A PubMed search yielded 319 suitable studies since 1930 in the English literature with 1984 cases of UrC including 1834 adenocarcinomas (92%) and 150 nonadenocarcinomas (8%). UrC was more common in men (63%), showed a median age at diagnosis of 50.8 years and a median tumor size of 6.0 cm. No associations were noted for overall survival and progression-free survival (PFS) and clinicopathological factors beside a favorable PFS in male patients (p = 0.047). The immunohistochemical markers found to be potentially helpful in the differential diagnostic situation are AMACR and CK34βE12 (UrC versus CRC and PBAC), CK7, β-Catenin and CD15 (UrC and PBAC versus CRC), and CEA and GATA3 (UrC and CRC versus PBAC). Serum markers like CEA, CA19-9 and CA125 might additionally be useful in the follow-up and monitoring of UrC.

High-grade neuroendocrine carcinoma of the urachus-report of 3 cases

Most urachal malignancies are composed of pure adenocarcinoma with mucin production. Urachal neuroendocrine carcinoma (NEC) is extremely rare, with only a few cases reported in the literature. Here we report 3 cases of urachal NEC, the largest series of this rare disease from a single institution. The patients were young, with a mean age of 27 years (range, 23-34). The urachal tumors showed 2 distinct components: high-grade NEC and enteric-type adenocarcinoma. The urachal NECs were composed of small cell carcinoma (n=2) or large cell NEC (n=1). The subsequent resection specimens showed that all the tumors were at advanced Sheldon stages. All 3 patients developed metastases, which were composed of NEC exclusively. Two patients died from disease in 10 and 31 months, respectively, and the third patient was alive with widespread metastases at 21 months. Our findings suggest that urachal NEC is an aggressive variant with an overwhelming growth advantage over conventional adenocarcinoma. The presence of high-grade NEC in the urachus is associated with poor prognosis.

Genetics and biological markers in urachal cancer

Urachal cancer (UraC) is a rare tumor entity that usually develops at the basis of the remnant embryologic urachus. Consisting of mostly adenocarcinomas, most patients present with secondary symptoms due to an advanced stage with urinary bladder infiltration. One third of patients are already metastasized at presentation rendering them unsuitable for curative surgical treatment. In order to improve staging, treatment and follow-up, adequate knowledge about the genetic origin and potential markers is necessary. This paper reviews the English literature until December 2015. Pathologists argue for and against metaplasia or remnant enteric cells as origin for the adenomatous tissue found in UraC. Mutations in KRAS, BRAF, GNAS and Her2 have been associated with UraC. Immunohistochemical (IHC) markers like CEA, 34βE12, Claudin-18 and RegIV are indicative for mucous producing UraC. So far, IHC markers fail as prognosticators when matched to clinical data. Little is known about serum markers for UraC. CEA, CA19-9, CA125 and CA724 are mentioned as being elevated in UraC by some reports. Regarding the literature for biological markers in UraC, knowledge is mostly derived from case reports or cohort studies mentioning markers or predictors. More genetic research is needed to show whether UraC stems from progenitor cells of the cloaca or is due to metaplasia of transitional cells. Few IHC markers have shown indicative potential for UraC. A useful panel for differential diagnostics and clinicopathologic prognostication needs to be developed. Serum markers show very little potential for neither diagnosis nor follow-up in UraC. Further research on larger cohorts is necessary.

Urachal adenocarcinoma that metastasized to breast was misinterpreted as primary breast mucinous carcinoma: A rare case report and literature review

BACKGROUND

The urachus is a vestigial tubular structure that connects the urinary bladder to the allantois during early embryonic development. Urachal carcinoma develops in the urachus, which is an embryological remnant of the urogenital sinus and allantois. The estimated annual incidence of urachal carcinoma in the general population is 0.01% of all cancers in adults. Moreover, urachal carcinoma accounts for 0.34% to 0.7% of all bladder carcinoma cases. And breast metastasis is extremely rarer.

METHODS AND RESULTS

A 42-year-old woman was admitted to our hospital with a palpable mass in the outer upper quadrant of the right breast, which was misinterpreted as a carcinoma that originated from the breast. Subsequently, she underwent surgery without any further meticulous examination. Immunohistochemistry analysis revealed positivity for CK20, Villin, and CDX-2 and negativity for CK7. After further inspection, a mass was found in the bladder dome using 18F-fluorodeoxyglucose positron emission tomography and computed tomography. The mass was surgically removed.

CONCLUSION

Pathologic and immunohistochemical examination confirmed that the mass was urachal mucinous adenocarcinoma and mucinous adenocarcinoma to the right breast. The patient has been followed up without recurrence for 8 months.

Urachal adenocarcinoma incidentally discovered in a young woman at elective caesarean section

Urachal adenocarcinoma is a rare non-urothelial malignancy that represents only 0.5% of all vesical cancers. Urachal adenocarcinoma most commonly occurs in the 5th to 7th decade. We describe a case of a 35-year-old woman (G3P1) who presented at 20 weeks pregnancy with two episodes of post-coital bleeding. Ultrasound demonstrated a uterine mass measuring 59×43×56 mm, presumed to be a leiomyoma. The decision was made to proceed to caesarean section at 38 weeks, given the progression of the presumed leiomyoma. A 2 cm bladder dome mass was incidentally discovered at the time of the caesarean section and an urgent intraoperative urology consult was sought. Resultantly, the bladder mass was dissected to the dome, and pathology returned urachal adenocarcinoma. This case report considers the treatment decisions involved when faced with urachal adenocarcinoma and reviews the literature surrounding this rare malignancy.

Small cell carcinoma of the urinary bladder: changing trends in the current literature

Background Extrapulmonary small cell carcinoma (SmCC), also known as oat cell carcinoma or small cell neuroendocrine carcinoma, is characterized by an aggressive clinical course with early metastasis pattern and a short life expectancy. So far, there is no prospective, data-based case-control study due to its low incidence. The purpose of this paper is to discuss the epidemiology, morphopathology, clinical characteristics, differential diagnosis and treatment of bladder SmCC in the light of the literature. Scope PubMed and American Society of Clinical Oncology Meeting abstracts were searched according to the following keywords: 'extrapulmonary SmCC', 'bladder cancer', and 'therapeutic approach'. The last search was performed on 1 October 2015. Some additional papers were determined by reviewing references of the appropriate articles. Most of the data regarding small cell carcinoma of the urinary bladder (SmCCB) were found to be based on the retrospective trials. Findings Bladder SmCC is more frequent in men and usually appears in the seventh to eighth decades. Macroscopic hematuria is the most common clinical symptom. The diagnosis of SmCCB is performed based on the same criteria determined by the WHO classification for the diagnosis of small cell lung carcinoma (SCLC). Prognosis is closely correlated with the stage at presentation. Although the prognosis of the disease is poor, a long survival can be achieved particularly by radical surgery following neoadjuvant chemotherapy in patients with early stage tumors. Cystectomy is still the current standard local treatment. However, cystectomy alone is not sufficient. Chemotherapy and definitive radiotherapy should be preferred for limited disease in patients who are not candidate for surgery. Conclusion Considering the poor prognosis of the disease, further studies are needed to determine the optimal treatment options and new molecular markers in the way of early diagnosis and favorable outcomes. Prospective, multicenter, randomized studies are required to evaluate the role of neoadjuvant chemotherapy followed either by surgery or radiotherapy.

"Mucin"-secreting papillary renal cell carcinoma: clinicopathological, immunohistochemical, and molecular genetic analysis of seven cases

Mucin and mucin-like material are features of mucinous tubular and spindle renal cell carcinoma (MTS RCC) but are rarely seen in papillary renal cell carcinoma (PRCC). We reviewed 1311 PRCC and identified 7 tumors containing extracellular and/or intracellular mucinous/mucin-like material (labeled as PRCCM). We analyzed these using morphological, histochemical, immunohistochemical, and molecular genetic methods (arrayCGH, FISH). Clinical data were available for six of the seven patients (five males and one female, age range 61-78 years). Follow-up was available for four patients (2-4 years); one patient died of widespread metastases. Tumor size ranged from 3 to 5 cm (mean 3.8). Of all cases, histological architecture showed a predominantly papillary pattern. Mucin or mucin-like was extracellular in one, intracellular in three, and both intra/extracellular in three cases. All tumors were positive for AMACR, vimentin, and OSCAR, while CK7 was positive in four. Mucicarmine stain was positive in all cases, PAS in six and Alcian blue in three cases. Five tumors were positive for MUC 1, but none were positive for MUC 2, MUC 4, or MUC 6. In only four cases, genetic analysis could be performed. Gain of chromosomes 7 and 17 was found in two cases; gain of 17 only was found in one case. Loss of heterozygosity of 3p was found in one case together with polysomy of chromosomes 7 and 17. No abnormalities of VHL, fumarate dehydrogenase, and TFE3 genes were detected. We conclude that PRCCM is a rare but challenging subtype of RCC that deserves to be further studied. In all the tumors, the mucin-like material was found in those stained with mucicarmin, but other conventional and immunohistochemical stains did not reveal consistent features of a single mucin. The molecular-genetic profile of these tumors was most consistent with that of typical papillary RCC, although one case had mixed genetic features of papillary and clear RCC. PRCCM has metastatic potential, as evidenced by one case with widespread metastases. It remains to be determined whether PRCCM represents a unique tumor subtype, deserving to be distinguished from other subtypes of PRCC.

Updates in the Pathologic Diagnosis and Classification of Epithelial Neoplasms of Urachal Origin

Since the publication of the World Health Organization "blue book" in 2004, several recent studies have provided new insights on the pathologic aspects of urachal neoplasms. The proposed updates include modified criteria for the diagnosis of urachal carcinoma. A uniform nomenclature for cystic tumors was lacking, and it is recommended that urachal mucinous cystic tumors should be separated and classified in a manner similar to ovarian mucinous neoplasms. The spectrum includes mucinous cystadenoma, mucinous cystic tumor of low malignant potential, mucinous cystic tumor of low malignant potential with intraepithelial carcinoma, and microscopically or frankly invasive mucinous cystadenocarcinoma, with 65% of cystic tumors classified as mucinous cystic tumor of low malignant potential. Most importantly, it has been shown that progression-free survival of noninvasive mucinous cystic tumors is significantly better than noncystic invasive adenocarcinoma. This development, along with prior descriptions of urachal villous adenoma, has also reaffirmed the occurrence of benign tumors of urachal epithelial origin. For noncystic (usual) invasive adenocarcinomas, the traditionally described histologic subtypes of enteric, mucinous, signet ring cell, not otherwise specified, and mixed remain appropriate, with 50% of tumors classified as mucinous subtype. Although this subtyping is helpful in diagnosis and differential diagnosis, the clinical significance of subtyping adenocarcinoma is still uncertain. Rare nonglandular morphologies such as urothelial, squamous, and neuroendocrine carcinoma in urachal carcinomas have been described in detail with proposals for their own set of diagnostic criteria. These criteria are based on unique features of urachal nonglandular carcinomas. Among the immunomarkers studied, only β-catenin and CK7 may be of help in the distinction of urachal from colorectal adenocarcinoma. Awareness of the expression profile of immunomarkers such as CDX2, P504S (racemase), PSMA, claudin-18, and REG IV in urachal tumors and in tumors in the differential diagnosis is important to avoid overreliance of these markers in the diagnosis. Limited studies have identified KRAS mutations interestingly only in mucinous adenocarcinoma and exclusive of MSI loss, and mutations in BRAF are not present. Several alternative tumor staging approaches (eg, Mayo, Ontario, TNM systems) different from the traditional staging proposed by Sheldon are used that provide better tumor distribution across stages; however, the prognostic utility of the stage substratification has yet to be validated in large prospective studies. Evidence though suggests that staging urachal cancer is most pertinent when dichotomized to tumors that have spread outside versus within the perivesical tissue. Only high tumor stage and residual tumor after surgery have been shown to be independent predictors of outcome. This review updates the contemporary classification of urachal epithelial tumors, which has informed the upcoming 2016 classification of World Health Organization tumors. We provide modified criteria for diagnosing urachal adenocarcinomas, which remains a clinico-pathologic exercise. The role of ancillary diagnostic methodology and issues pertaining to staging and prognostication are presented.

Urachal carcinoma: a pathologic and clinical study of 46 cases

Urachal carcinoma is a rare tumor that has not been well studied. To determine the pathologic and clinical features of this disease, we retrospectively evaluated 46 cases from our surgical pathology files. The patients included 16 women and 30 men, with a mean age of 53.4 years (range, 28-82 years). Forty patients had undergone cystectomy, and the remaining 6 had undergone transurethral bladder biopsy. Most tumors were located at the dome (n = 44); only 2 were located at both the dome and anterior wall. All tumors consisted of adenocarcinoma, including mucinous (n = 36), enteric (n = 7), not otherwise specified (n = 2), and signet ring cell (n = 1) types. Focal areas of signet ring cell features were present in 23 cases, but urothelial carcinoma in situ was not identified in any cases. The tumors invaded the muscularis propria (n = 8), perivesical adipose tissue (n = 27), and abdominal wall (n = 3). Twenty-five patients had died of cancer at a mean of 32 months (range, 12-74 months), and 21 patients were alive at a mean of 65 months (range, 7-230 months). The median cancer-specific survival time of urachal adenocarcinoma patients was 45 months, which was significantly longer than that of bladder urothelial carcinoma patients with similar-stage disease (P = .047). Patients' cancer-specific survival was associated with tumor stage according to the Sheldon, Mayo, and TNM staging systems. In conclusion, urachal carcinomas are predominantly composed of invasive adenocarcinomas, which commonly demonstrate mucinous features. Most tumors present at advanced stages but are still associated with a better survival rate than bladder urothelial carcinomas.

Treatment Outcome and Relevance of Palliative Chemotherapy in Urachal Cancer

BACKGROUND

Urachal cancer is a rare malignancy that accounts for <1% of bladder cancers. There is currently no consensus on the diagnosis and management of urachal cancer and there are very few reports on palliative chemotherapy for unresectable disease. We delineate the clinical features and treatment outcome of urachal cancer, in particular the relevance of palliative chemotherapy in recurrent, metastatic disease.

METHODS

The clinicopathologic variables and treatment outcome of patients who were treated for urachal cancer were retrospectively reviewed.

RESULTS

Among 28 eligible patients, 25 had localized disease and 3 had metastatic disease at initial diagnosis. All patients with localized disease underwent curative resection and there was disease recurrence in 10. Out of 13 patients with metastatic disease either at initial diagnosis or during follow-up, the lung was the most common metastatic site (n = 5), followed by the liver, bone and peritoneum. Ten patients received palliative chemotherapy. A total of 24 chemotherapeutic regimens were administered; regimens with a base of fluoropyrimidine (5-FU), taxane and gemcitabine were the most common. The overall response rate of all chemotherapeutic regimens was 16.7%. The 5-FU-based regimens showed a good response, with 2 of 4 patients who received these showing a partial response. One tumor with a partial small-cell component showed a partial response to both an etoposide-based regimen and a taxane-based regimen.

CONCLUSIONS

In urachal cancer, curative surgery is still the recommended treatment with respect to overall survival. A 5-FU-based chemotherapy regimen could be considered for metastatic recurrent disease.

Prognostic factors for urachal cancer: a bayesian model-averaging approach

Purpose

This study was conducted to evaluate prognostic factors and cancer-specific survival (CSS) in a cohort of 41 patients with urachal carcinoma by use of a Bayesian model-averaging approach.

Materials and Methods

Our cohort included 41 patients with urachal carcinoma who underwent extended partial cystectomy, total cystectomy, transurethral resection, chemotherapy, or radiotherapy at a single institute. All patients were classified by both the Sheldon and the Mayo staging systems according to histopathologic reports and preoperative radiologic findings. Kaplan-Meier survival curves and Cox proportional-hazards regression models were carried out to investigate prognostic factors, and a Bayesian model-averaging approach was performed to confirm the significance of each variable by using posterior probabilities.

Results

The mean age of the patients was 49.88±13.80 years and the male-to-female ratio was 24:17. The median follow-up was 5.42 years (interquartile range, 2.8-8.4 years). Five- and 10-year CSS rates were 55.9% and 43.4%, respectively. Lower Sheldon (p=0.004) and Mayo (p<0.001) stage, mucinous adenocarcinoma (p=0.005), and larger tumor size (p=0.023) were significant predictors of high survival probability on the basis of a log-rank test. By use of the Bayesian model-averaging approach, higher Mayo stage and larger tumor size were significant predictors of cancer-specific mortality in urachal carcinoma.

Conclusions

The Mayo staging system might be more effective than the Sheldon staging system. In addition, the multivariate analyses suggested that tumor size may be a prognostic factor for urachal carcinoma.

Non-invasive, low-grade papillary urothelial carcinoma in the urachus

The urachus is a duct connecting the allantois with the fetal bladder, forming the median umbilical ligament; it usually obliterates during fetal life. Carcinomas arising from urachal remnants are rare but associated with a poor prognosis. We present one case of non-invasive urachal papillary urothelial carcinoma, and through a systematic literature search, we identified 12 additional cases of urachal urothelial carcinoma reported in English literature in the past 20 years. The cases were compared according to the Sheldon Staging System and the Mayo Staging System presented by Ashley et al in 2006, and both Staging Systems tend to predict clinical outcome. The urachal carcinoma is an important differential diagnosis in patients presenting with haematuria or an infraumbilical mass, because the symptoms may be sparse and diagnosis at an early stage is essential for successful treatment.

[Urachal cancers]

Urachal cancer is a rare pathology (less than 1% among all bladder tumors) with a poor prognosis for all stages, because of clinical delay leading to a late diagnosis, difficult differential diagnosis with bladder cancer, and no consensus for the treatment, mostly about the chemotherapy for advanced stages, because there are no data from prospective studies. A surgical treatment can be performed for the localized stages, but there are no real guidelines for local relapses and metastatic progression treatment. Those cancers are not radio- or chemosensitive; nevertheless data from fundamental research are missing. As this pathology is really uncommon, there are no clinical studies with targeted therapies. The purpose of this review is to introduce the most important clinical and paraclinical features of those cancers, and the usual treatment performed.