Publications by authors named "Sean Williamson"

Intrarenal hemangiomas lack concise clinicopathologic information, due to the predominance of single case reports and inclusion of other vascular neoplasms and hemangiomas of perirenal, hilar, and renal vein origin. Herein, in this multi-institutional study we evaluate clinicopathologic features of 39 intrarenal hemangiomas. The median age was 62 years (range = 27-94 years; 2:1 male to female ratio), with left-sided predominance (left = 21, right = 13; one case was bilateral).

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Juxtaglomerular cell tumor (JxGCT) is a rare type of renal neoplasm demonstrating morphologic overlap with some mesenchymal tumors such as glomus tumor (GT) and solitary fibrous tumor (SFT). Its oncogenic drivers remain elusive, and only a few cases have been analyzed with modern molecular techniques. In prior studies, loss of chromosomes 9 and 11 appeared to be recurrent.

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Objectives: Urothelial carcinoma in situ (CIS) with early papillary formation is terminology sometimes used to suggest incipient high-grade papillary urothelial carcinoma (PUC) but may lead to confusion between true CIS and lateral flat spread of PUC.

Methods: It remains unclear how pathologists and urologists interpret this scenario, so a survey was circulated to 68 pathologists (group 1 = 28 academic genitourinary pathologists; group 2 = 17 pathologists with a self-reported genitourinary focus; group 3 = 23 pathologists self-reported as not genitourinary specialists) and 32 urologists.

Results: Regarding atypical urothelial lesions that appear mainly flat but contain possible papillae, group 3 was more likely to label this as CIS compared with groups 1 and 2 (35% for group 3 vs 13% for groups 1 and 2), while groups 1 and 2 more often adopted another descriptive diagnosis, such as "CIS with early papillary features" (38% for groups 1 and 2 vs 13% for group 3).

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  • Pathogenic mutations in genes associated with tuberous sclerosis complex (TSC) affect various types of kidney tumors like eosinophilic solid and cystic renal cell carcinoma (ESC RCC) and oncocytic tumors.
  • A study validated a TSC2 immunohistochemistry (IHC) assay on tissues from renal tumors to assess the presence of TSC2 mutations, achieving high predictive values for diagnosing these tumors.
  • The findings highlight that TSC2 IHC can help identify renal tumors linked to TSC/mTOR pathway mutations, supporting its use in diagnostic processes.
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  • Synovial sarcoma (SS) is a rare type of cancer, primarily found in genitourinary tissues, commonly linked to the SS18::SSX gene fusion, and its paratesticular occurrence is extremely uncommon, with only 4 documented cases prior to this study.
  • This research details the characteristics and genetic profile of the largest cohort of paratesticular SS patients, analyzing data from 14 individuals aged 15 to 47, all of whom underwent surgical removal of the tumors and some received chemotherapy.
  • The findings indicate a generally poor prognosis for paratesticular SS even after aggressive treatment, emphasizing the need for thorough diagnostic methods to differentiate it from similar conditions, and supporting the use of SS18-SS
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  • The study investigates the occurrence of rete hyperplasia and hyaline globules in germ cell tumors, with a focus on their potential to mimic yolk sac tumors, noting a significant misdiagnosis risk over the years.
  • Out of 348 evaluated orchiectomies, 30% showed rete hyperplasia and/or hyaline globules, often without any yolk sac tumor component, suggesting a complexity in tumor classifications.
  • The findings highlight the importance of accurately identifying these histological features, as they may indicate underlying testicular obstruction due to the tumor, which is crucial for proper treatment decisions.
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  • Pure intertubular seminoma (PITS) is a rare type of testicular cancer where seminoma cells are found in testicular interstitium without forming a noticeable mass or diffuse growth, leading to challenges in diagnosis.
  • This condition often goes unnoticed and is usually diagnosed incidentally during evaluations for testicular pain, infertility, or other issues, with only a minority of cases presenting with metastasis.
  • A study involving 15 patients revealed that the average age at presentation was 29, and common symptoms included undescended testis, testicular pain, and infertility, while most patients had normal serum markers and no visible tumors at the time of diagnosis.
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  • - Oncocytic renal neoplasms pose significant diagnostic challenges, yet are generally nonaggressive, prompting discussion about the necessity of differentiating emerging subtypes like eosinophilic solid and cystic renal cell carcinoma and others.
  • - A survey of 63 urologic pathologists revealed that many encounter complex oncocytic tumors frequently, with 70% agreeing that eosinophilic solid and cystic renal cell carcinoma should be recognized as a distinct category, while opinions were more divided on other types.
  • - Diagnostic approaches varied among pathologists, with 60% hesitant to diagnose oncocytoma through needle biopsies, and a near split on the routine use of immunohistochemistry; common genetic testing was
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  • This study investigates the characteristics of 10 rare primary renal perivascular epithelioid cell tumors (PEComas) that have a specific genetic alteration (Xp11.2 translocation), focusing on their presentation and outcomes.
  • The patient group included both genders aged 14-65, with positive outcomes for most after surgical treatment, and showed consistent expression of certain markers (TFE3 being the most significant) while lacking others typically seen in similar tumors.
  • The findings reveal the genetic variety among these tumors, with unique TFE3 fusion partners identified, and emphasize the importance of TFE3 immunohistochemistry for diagnosis and differentiation from other kidney cancers.
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  • Cowper glands can sometimes be mistaken for prostatic adenocarcinoma in prostate biopsies, especially when the tissue samples are incomplete or distorted.
  • Immunohistochemistry can help differentiate between the two, but traditional prostate-specific markers may show positive results in Cowper glands, which can lead to confusion.
  • This study found that basal markers like high molecular weight keratin and p63 are more reliable for identifying Cowper glands, while prostate-specific markers should be used cautiously to avoid misdiagnosis.
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  • * The survey received an 85% response rate from 98 uropathologists, revealing strong agreement on distinguishing between luminal and basal UC types, but varied opinions on the importance of certain genetic tests like FGFR3 and TERT promoter mutations.
  • * Most uropathologists acknowledged the aggressive nature of tumors with micropapillary features and favored further evaluation and specific molecular testing for aggressive subtypes, indicating a need for improved consensus in UC classification and treatment strategies.
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  • Pathologic re-review of TURBT specimens at a tertiary care center was evaluated to understand its impact on disease risk stratification for bladder cancer patients.
  • Out of 173 patients whose specimens were re-reviewed, changes in grade, clinical stage, and risk stratification were observed, particularly in those with less advanced (
  • The study found that re-review by a GU pathologist affected more than 20% of patients' risk assessments, highlighting its importance in potentially altering patient management strategies.
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Acquired cystic disease associated renal cell carcinomas (ACD-RCC) are rare and their molecular and histopathological characteristics are still being explored. We therefore investigated the clinicopathologic and molecular characteristics of 31 tumors. The patients were predominantly male (n = 30), with tumors mainly left-sided (n = 17), unifocal (n = 19), and unilateral (n = 29) and a mean tumor size of 25 mm (range, 3-65 mm).

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Juxtaglomerular cell tumor (JGCT) is a rare neoplasm, part of the family of mesenchymal tumors of the kidney. Although the pathophysiological and clinical correlates of JGCT are well known, as these tumors are an important cause of early-onset arterial hypertension refractory to medical treatment, their molecular background is unknown, with only few small studies investigating their karyotype. Herein we describe a multi-institutional cohort of JGCTs diagnosed by experienced genitourinary pathologists, evaluating clinical presentation and outcome, morphologic diversity, and, importantly, the molecular features.

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  • Chromophobe renal cell carcinoma (RCC) can display various morphological patterns, but a new subtype resembling upper urothelial tract micropapillary carcinoma (MPC) has been identified, marked by extensive stromal retraction.
  • A study reviewed 12 nephrectomies of MPC-like chromophobe RCC, predominantly affecting older men, with tumors averaging 6.4 cm, and a diverse range of pathological stages.
  • Molecular testing revealed a high prevalence of chromosomal losses and mutations in notable genes, yet follow-up indicated that patients generally showed no evidence of disease, emphasizing the importance of recognizing this variant to prevent misdiagnosis.
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Urothelial carcinoma and prostatic adenocarcinoma can have overlapping histologic features and in some instances pose challenges to pathologists. GATA binding protein 3 (GATA3) immunohistochemistry (IHC) is a well-established tool to aid in this specific diagnostic dilemma as it has been shown to be a sensitive marker for urothelial carcinoma and a putatively specific marker in excluding prostatic adenocarcinoma. However, in encountering an index tumor of prostatic adenosquamous carcinoma positive for GATA3, herein we sought to investigate this potential diagnostic pitfall in a larger series of tumors.

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After hatching, sea turtles leave the nest and disperse into the ocean. Many years later, they return to their natal coastlines. The period between their leaving and their returning to natal areas, known as the "Lost Years", is poorly understood.

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  • Inflammation in prostate cancer involves changes in T and B cell levels, and the study investigates how these changes affect disease progression.
  • The research analyzed 73 prostate cancer cases, measuring lymphocyte counts in pre- and postoperative samples from benign and malignant tissue using specific staining techniques.
  • Findings indicate that higher levels of CD20+ lymphocytes in benign tissue adjacent to tumors are linked to a lower risk of cancer recurrence, highlighting the importance of immune response modulation in cancer prognosis.
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Introduction: As the list of histologic parameters to include in surgical pathology reports of prostate cancer biopsies grows, some pathologists include this information in the microscopic description or summary sections of the report, whereas others include it in the "topline" or final diagnosis section. This prompted us to develop a multi-institutional survey to assess reporting trends among genitourinary (GU) pathologists.

Methods: A survey instrument was shared among 110 GU pathologists via surveymonkey.

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Aims: The 2022 WHO classification for kidney tumours recently downgraded clear cell tubulopapillary (also known as clear cell papillary) renal cell carcinoma (RCC) to a benign neoplasm (i.e. clear cell tubulopapillary renal cell tumour) based on the overwhelmingly banal nature of this neoplasm.

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  • The rise of new types of kidney tumors, especially those defined by specific molecular characteristics, is creating challenges for pathology labs due to their rarity and lack of clear features.
  • Diagnosing these tumors requires identifying specific molecular changes, which many labs are not equipped to handle due to limited resources or cost issues.
  • Pathologists need to stay informed about the latest developments in renal neoplasms and understand the constraints of their current diagnostic capabilities.
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Mechanistic target of rapamycin kinase (mTOR) is a member of the phosphatidylinositol-3-hydroxide kinase (PI3 K)-related protein kinase family that functions as a central regulator of cell growth, metabolism, proliferation, and survival. The role of the TSC-mTOR signaling pathway in kidney tumors has been implicated in some hamartoma syndromes; however, with the advent and wide utilization of molecular studies, a growing number of kidney tumors have been linked to somatic or germline mutations involving genes that encode for this pathway, including eosinophilic solid and cystic renal cell carcinoma, low-grade oncocytic tumor, eosinophilic vacuolated tumor, renal cell carcinoma with fibromyomatous stroma and angiomyolipoma, among others. Herein, we review the contemporary developments of mTOR pathway-related renal neoplasia, focusing on the clinicopathologic features of the tumor entities.

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  • Neoadjuvant chemotherapy (NACT) is recommended for treating muscle-invasive bladder cancer, but the current guidelines for examining specimens after treatment are unclear.
  • A survey conducted among pathologists and their assistants revealed that gross tumors are often not identified, with 29% of cases showing no gross lesions at all.
  • There is a strong interest among responders for standardized protocols in examining and reporting post-NACT cystectomies to improve consistency in practice.
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