WHO Histological Classification Research Articles

P1.16-002 Management of Local Recurrence after Segmentectomy for Stage IA Lung Cancer

Segmentectomy is thought to be able to spare lung parenchyma compared with lobectomy. On the other hand it might cause more local recurrences. The management of local recurrence after segmentectomy is thought to be an important issue. The aim of this study is to evaluate the management of local recurrence after segmentectomy. From June 2005 to March 2009 we performed segmentectomy for clinical stage IA lung cancer, 88 male and 91 female with mean age of 66 year-old (32-83). The histological types of 179 lung tumors according to WHO histological classification are as follows: atypical adenomatous hyperplasia (2), adenocarcinoma in situ (34), minimally invasive adenocarcinoma (27), invasive adenocarcinoma (96), Squamous cell carcinoma (2), adenosquamous carcinoma (4), and carcinoid (2), respectively. Median follow-up time was 2920 days. During follow up there were 15 recurrences. Of 15 cases with recurrence 6 cases had local recurrences without distant metastasis. Mean time to local recurrence after segmentectomy was 1595 ± 1027 days (356－2965). Of 6 cases with local recurrence 5 cases had micropapillary component more than 5%. The initial treatments for local recurrence were as follows: completion lobectomy (4), radiation (1), radiofrequency ablation (1), respectively. Three of 6 cases have been alive without evidence of disease since initial treatment for local recurrence of lung cancer. Management of local recurrence after segmentectomy is important. Local treatment, such as, completion lobectomy, radiation, or radio frequency ablation may effective for selected cases.

Risk factors of myasthenic crisis after thymectomy for thymoma patients with myasthenia gravis.

Total thymectomy should be performed on thymoma patients with myasthenia gravis. The aim of the present study was to investigate the risk factors of postoperative myasthenic crisis (POMC) occurrence in these patients. The clinical records of 127 thymoma patients with myasthenia gravis (68 men, 59 women; median age, 50 years) who underwent total thymectomy at our institution from 2005 to 2014 were retrospectively reviewed. The following factors were analysed in relation to POMC: gender, age, duration of symptoms, bulbar symptoms, smoking history, history of myasthenic crisis, comorbidities, perioperative pyridostigmine and prednisolone therapy, spirometric and blood gas parameters, Osserman stage, operation approach, major complications, World Health Organization (WHO) histologic classification, Masaoka stage and use of immunoglobulins or plasmapheresis. Thirteen patients (10%) experienced POMC and required intubation. All patients were weaned after 2-28 days (median 9 days) and were discharged. Univariate analysis revealed a correlation between POMC and Osserman-stage IIA-IV [odds ratio (OR) = 4.928, 95% confidence interval (CI) = 1.286-18.882, P = 0.01], bulbar symptoms (OR = 3.828, 95% CI = 1.112-13.176, P = 0.04), and forced expiratory volume in one second <70% pred forced expiratory volume in one second (OR = 4.856, 95% CI = 1.380-17.081, P = 0.02). In addition, more frequent POMC occurred in WHO type B2-B3 than in type A-B1 thymomas (OR = 8.118, 95% CI = 1.020-64.590, P = 0.03). Multivariate logistic regression analysis showed that WHO histologic classification B2-B3 (OR = 10.041, 95% CI = 1.228-82.090, P = 0.03) and Osserman-stage IIA-IV (OR = 5.953, 95% CI = 1.506-23.538, P = 0.01) independently predicted POMC. Osserman stage (IIA-IV) and WHO type B2-B3 thymomas are independent predictors of POMC in thymoma patients with myasthenia gravis who have undergone total thymectomy. Thus, adequate perioperative care should be provided to these patients.

Assessment of the ITMIG Statement on the WHO Histological Classification and of the Eighth TNM Staging of Thymic Epithelial Tumors of a Series of 188 Thymic Epithelial Tumors

IntroductionThymic epithelial tumors (TETs) are rare intrathoracic malignancies that are categorized histologically according to the WHO classification, which was recently updated in 2015 on the basis of a consensus statement of the International Thymic Malignancy Interest Group (ITMIG); at the same time, the standard Masaoka-Koga staging system is scheduled to be replaced by the eighth edition of the TNM staging classification by the American Joint Committee on Cancer/Union for International Cancer Control consortium. Our objectives were to analyze the feasibility of assessing ITMIG consensus major and minor morphological and immunohistochemical criteria and the eighth edition of the TNM staging classification in a routine practice setting. MethodsThis is a single-center study conducted at the Louis-Pradel Hospital of Lyon University, one of the largest centers for TETs in France. Overall, a large surgical series of 188 TETs diagnosed in 181 patients between 2000 and 2014 at our center were analyzed. ResultsThere were 89 men (49%) and 92 women (51%); 57 patients (31%) presented with myasthenia gravis at time of diagnosis. According to the WHO classification, there were nine type A thymomas (5%), 67 type AB thymomas (36%), 19 type B1 thymomas (10%), 46 type B2 thymomas (24%), 27 type B3 thymomas (14%), and 20 thymic carcinomas (11%). ITMIG consensus major criteria were identified in 100% of type A, AB, B1, and B2 thymomas. After restaging according to the eighth edition of the TNM staging classification, there were 127 stage I (84%), three stage II (2%), 17 stage IIIa (11%), no stage IIIb, two stage IVa (1%), and three stage IVb (2%) thymomas. Significant correlation between histological type and stage at diagnosis was maintained after restaging according the TNM classification. ConclusionComprehensive analysis of our well-characterized surgical series of 188 TETs indicates the feasibility and the diagnostic value of the ITMIG consensus statement on WHO histological classification and highlights the major switch in staging when the eighth edition of the TNM staging classification is applied.

Long term oncological outcome of thymoma and thymic carcinoma - an analysis of 235 cases from a single institution.

Background and objectivesThymoma has a variable long-term oncological outcome after surgical resection. Survival and tumor recurrence were analyzed to determine the predisposing factors for tumor recurrence.MethodsA total of 235 patients who underwent surgery for thymoma or thymic carcinoma from December 1997 to March 2013 were analyzed using Masaoka staging system and World Health Organization (WHO) histological classification. Surgical intervention included extended thymothymectomy via median sternotomy and thymomectomy via thoracotomy/ video-assisted thoracoscopic surgery (VATS).ResultsThe median duration of follow-up was 105 months (12–198 months). Among these 235 patients, recurrence was observed in 25 patients (10.7%). according to Masaoka stage I, IIA, IIB, III, IVA, IVB, recurrence rates were 1/65(1.5%), 8/106(7.5%), 1/32(3.1%), 6/20(30.0%), 8/10(80.0%), 1/1(100.0%), respectively. Disease or treatment-related mortality was observed in 13 patients. Overall survival rate was 94.4%. After univariate analysis, predisposing factors for tumor recurrence included Masaoka stage, WHO histologic type, tumor size, adjuvant therapy and margin status.ConclusionsDue to the indolent behavior of thymoma, tumor recurrence appears to be a better assessment of oncological outcome rather than survival. Factors associated with tumor recurrence include Masaoka stage, WHO histologic type, tumor size, adjuvant therapy and margin status.

Frequency of Ovarian Tumors According to WHO Histological Classification and Their Association to Age at Diagnosis

Ovarian tumors, or ovarian neoplasms, are benign or malignant tumors arising from the ovaries. They may arise from any of the three components of ovary i.e. surface epithelium, germ cells and the stroma of the ovary including sex cords. Tumors in the ovary can also be secondary or metastatic tumors.Objective: To determine the frequency of Ovarian Tumors according to WHO Histological classification and their relation to age at diagnosis in almost one year.Methods: A cross-sectional study was carried out, that included all the consecutive cases of ovarian neoplasms diagnosed at the Pathology department of a public sector university in Lahore from 1 January 2015 to 13 February 2016.Results: In 95 female patients diagnosed with ovarian tumors, the mean age was found to be 29.58 ±11.493 with a range of 3-65 years. Tumors were most common between the ages of 15 to 30 years. The highest rates of malignancy were in the 0-15 and 45-60 age groups (Figure 1). About 78.9% of the tumors (75/95) were benign, 1.1% (1/95) were borderline and 20% (19/95) were malignant (Figure 3), 72.6% (69/95) were epithelial tumors, 23.2% (22/95) were germ cell and 4.2% (4/95) were sex cord stromal tumors (Figure 4). Among the 95 cases, serous tumors were the most common (49.5%), followed by mucinous (16.8%) and teratomas (15.8%).Conclusion: According to our study, ovarian tumors were common between the age of 15 to 29 years. Benign neoplastic lesions were more common than malignant neoplastic lesions. The frequency of malignant and benign ovarian neoplasms found in our research differed from other studies conducted in Pakistan. There is a significant association of ovarian tumors in age less than 30 year as compared to older age groups (P &lt; 0.001).

Molecular analysis of thymic epithelial tumors (TETs): A report by The Cancer Genome Atlas (TCGA) research network.

8520 Background: Thymoma (T) and thymic carcinoma (TC) are the most common malignancies of the anterior mediastinum. Additionally, thymoma has an unique association with autoimmune disorders, notably myasthenia gravis (MG). Histologic classification of TETs has been largely based on the gross description of the epithelial cell appearance and the relative abundance of associated lymphocytes. A comprehensive molecular analysis of TETs has not heretofore been conducted. Methods: The TCGA Research Network conducted multi-platform analyses of 117 TETs (T = 105; TC = 10 and micronodular T = 2), which included whole-exome, transcriptome, methylome and targeted proteome analysis. Patient characteristics: median age = 60 years (range 17-84); M:F (%) = 52:48; Masaoka Stage (I-36, IIA-39, IIB-19; III-15; IVA-1; IVB-5); mg was present in 32 patients. No patient had prior therapy for metastatic disease, but 14 had prior chemotherapy and 39 had prior radiation therapy in adjuvant setting. WHO histologic classification (blinded review) revealed A = 10; A/B = 48, B1 = 12, B2 = 25, B3 = 10, micronodular T = 2 and TC = 10. Results: T has one of the lowest mutational loads of any tumor in the TCGA. A unique transcription factor, GTF2I, was the most commonly observed mutation in WHO Types A and A/B. All GTF2I mutations were exclusively at the amino acid 424 locus. This is the only tumor with this specific mutation within the entire TCGA database. HRAS, NRAS and TP53 mutations were less commonly noted among all TETs. Four distinct molecular-driven subtypes of TETs were identified that strongly correlated with the current WHO histologic classification. Increased aneuploidy and overexpression of muscle auto-antigens were associated with mg phenotype. Conclusions: Based on molecular analysis, four clusters were identified that correlated strongly with the current WHO Histologic Classification. Also identified was a unique mutation in GTF2I, which was associated with WHO Type A and A/B thymoma. This international effort represents the largest and most comprehensive molecular analysis of TETs conducted to date is expected to have important clinical and translational implications for this rare disease.

Long-term outcomes of 307 patients after complete thymoma resection

BackgroundThymoma is an uncommon tumor without a widely accepted standard care to date. We aimed to investigate the clinicopathologic variables of patients with thymoma and identify possible predictors of survival and recurrence after initial resection.MethodsWe retrospectively selected 307 patients with thymoma who underwent complete resection at the Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (Beijing, China) between January 2003 and December 2014. The associations of patients’ clinical characteristics with prognosis were estimated using Cox regression and Kaplan–Meier survival analyses.ResultsDuring follow-up (median, 86 months; range, 24–160 months), the 5- and 10-year disease-free survival (DFS) rates were 84.0% and 73.0%, respectively, and the 5- and 10-year overall survival (OS) rates were 91.0% and 74.0%, respectively. Masaoka stage (P < 0.001), World Health Organization (WHO) histological classification (P < 0.001), and postoperative radiotherapy after initial resection (P = 0.006) were associated with recurrence (52/307, 16.9%). Multivariate analysis revealed that, after initial resection, WHO histological classification and Masaoka stage were independent predictors of DFS and OS. The pleura (25/52, 48.0%) were the most common site of recurrence, and locoregional recurrence (41/52, 79.0%) was the most common recurrence pattern. The recurrence pattern was an independent predictor of post-recurrence survival. Patients with recurrent thymoma who underwent repeated resection had increased post-recurrence survival rates compared with those who underwent therapies other than surgery (P = 0.017).ConclusionsMasaoka stage and WHO histological classification were independent prognostic factors of thymoma after initial complete resection. The recurrence pattern was an independent predictor of post-recurrence survival. Locoregional recurrence and repeated resection of the recurrent tumor were associated with favorable prognosis.

Cystic lesions of the jaws: a retrospective clinicopathologic study of 2030 cases

The aim of this study was to perform an epidemiologic analysis of cases of jaw cysts treated from 1973 to 2012 at the Dentistry and Maxillofacial Surgery Unit of the Verona Hospital, Italy, and to compare the data obtained with those published in the literature. A retrospective survey of 2030 patients treated for jaw cysts from 1973 to 2012 was performed. The lesions were classified according to the 2005 World Health Organization histologic classification, and the following variables were analyzed: age, gender, histopathologic diagnosis, and site of onset. Of 2030 total lesions, there were 1970 odontogenic cysts (97.04%), 50 nonodontogenic cysts (2.46%), and 10 pseudocysts (0.49%). Of the patients, 314 were children (15.47%), and 1716 were adults (84.53%). Mean age was 37.24years, with a male/female ratio of 1.71:1. There is a wide variety of cysts, some of which are subject to variations according to gender, localization, and age.

Incidence trends in high-grade primary brain tumors in males and females.

The focus of the present review is to investigate whether there is a variation in the incidence rates between male and female patients with high-grade primary brain tumors and if there are altered incidence rates associated with the time at which they were diagnosed. Previous studies identified in internationally peer-reviewed journals were identified using a systematic search of the PubMed database. Due to the difficulties in data interpretation, studies that exclusively included patient data classified prior to the 2nd edition of the World Health Organization histological classification system of brain tumors were excluded. The overall incidence rates and incidence trends of male and female patients were analyzed separately. The mean age-adjusted overall incidence rate in the male population was 1.27 per 100,000 compared with 0.89 per 100,000 in the female population. The variance between the two genders differed and a Wilcoxon rank-sum test indicated that there was no significant difference in the incidence rate of high-grade primary brain tumors between males and females (P=0.3658). Furthermore, there was no significant difference in incidence rate trend between 1996-2004 and 2005-2010 for male or female populations (P=0.101 and P=0.472, respectively). The results from the present systematic review did not demonstrate a significant difference in incidence rate between the two genders. Therefore, the results from the current study are considered to be preliminary and further studies are required to elucidate this issue.

Higher IGFBP-1 to IGF-1 serum ratio predicts unfavourable survival in patients with nasopharyngeal carcinoma

BackgroundThe insulin-like growth factor (IGF) system plays an important role in the development and progression of cancer. However, little is known about the expression of the IGF system components and their clinicopathological significance and prognostic value in nasopharyngeal carcinoma (NPC).MethodsIGF system components (IGF-1, IGF-2, IGF-1SR, IGFBP-1, IGFBP-2, IGFBP-3, IGFBP-4 and IGFBP-6) were quantified from the plasma of NPC patients and healthy individuals using the RayBio Human Cytokine Antibody Array. IGFBP-1 and IGF-1 mRNA levels were quantified by real-time qPCR, and protein expression was detected by western blot in nine NPC cell lines and four immortalized nasopharyngeal epithelial (NPE) cell lines. Tissue-specific expression of IGFBP-1 and IGF-1 was detected by immunohistochemistry in paraffin-embedded NPC tissues. ELISA analysis was used to measure the serum levels of IGFBP-1 and IGF-1 in 142 NPC patients and 128 healthy controls and determine potential correlation with clinicopathological parameters.ResultsSignificantly higher levels of circulating IGFBP-1 and lower levels of IGF-1 and IGF-2 were detected in NPC patients compared to healthy controls by Cytokine Antibody Array analyses (P = 0.034, 0.012, 0.046, respectively). IGFBP-1 expression was detected in the majority of NPC cell lines, but not in NPE cell lines, and was shown to localize to the nucleus of tumour cells, in contrast to the cytoplasmic staining observed in normal cells. Importantly, IGFBP-1 expression was stronger in NPC tumour tissues compared to peritumoural tissues. In contrast, IGF-1 expression was weak or absent in NPC and NPE cell lines, with the exception of the EBV-infected C666 cell line, and was found to be expressed at lower levels in tumour tissues compared to tumour-adjacent normal tissue. Levels of serum IGFBP-1 were shown to be significantly higher in patients with NPCs compared to healthy control individuals (55.23 ± 41.25 μg/L vs. 32.08 ± 29.73 μg/L, P < 0.001), whereas serum levels of IGF-1 were significantly lower in NPC patients compared to healthy controls (98.14 ± 71.48 μg/L vs. 164.01 ± 92.08 μg/L, P = 0.001). Consistently, the IGFBP-1/IGF-1 serum ratio was shown to be significantly higher in NPC patients compared to healthy control individuals (P = 0.002). Serum levels of IGFBP-1 and the IGFBP-1/IGF-1 ratio significantly correlated with age (P = 0.020; P = 0.016), WHO histological classification (P = 0.044; P = 0.048), titre of EA (EB Virus Capsid Antigen-IgA) and NPC (P = 0.015; P = 0.016). In contrast, higher IGFBP-1 serum levels and IGFBP-1/IGF-1 ratio significantly correlated with poor RFS (P = 0.046; P = 0.037) and OS (P = 0.038; P = 0.009). Multivariate analysis revealed that the IGFBP-1/IGF-1 ratio, but not serum IGFBP-1 level, represents an independent risk factor for poor RFS (P = 0.044) and OS (P = 0.035).ConclusionsA higher IGFBP-1/IGF-1 serum ratio is significantly associated with poor prognosis in NPC patients.

Clinicostatistical observation of odontogenic tumors based on the WHO histological classification of 2005

Clinicostatistical observation of odontogenic tumors based on the WHO histological classification of 2005

Clinicopathologic characteristics and resection rates of papillary early gastric cancer removed by endoscopic submucosal dissection.

The aim of this study was to assess the: 1) clinicopathologic features of papillary early gastric cancer (PEGC) (13 cases) compared to tubular early gastric cancer (TEGC) (41 cases); 2) efficiency of endoscopic submucosal dissection (ESD) in treatment of PEGC. From January 2007 to February 2016, a total of 54 consecutive patients with early gastric cancer (EGC) underwent ESD at the Department of Gastroenterology of the Pomeranian Medical University in Poland. The histologic type of carcinoma was assessed according to the WHO histological classification of GC. The extension of GC into the submucosa was measured using the Aperio Scan Scope image analysis system tools. PEGCs were diagnosed in 24.1% of the cases of EGC. PEGCs were significantly more elevated in macroscopic examination and better demarcated tumors than TEGC. There were no significant differences between gender, tumor location, ulceration, tumor size, depth of invasion (T), presence of intestinal metaplasia and lymphocytic infiltrate. Curative resection was achieved in 87.1% of patients with EGCs treated with ESD. The lower rate of curative resection (R0) observed in PEGC (76.9%) vs TEGC (90.2%) was not statistically significant. Further studies will be necessary to confirm the clinical and morphological presentation of PEGCs.

Editorial on “assessment of the ITMIG statement on the WHO histological classification and of the 8th TNM staging of thymic epithelial tumors, of a series of 188 thymic epithelial tumors”

Thymic epithelial neoplasms are malignant tumors arising from the thymus that account for 0.2–1.5% of all malignancies but are the most common non-lymphomatous primary neoplasms of the anterior mediastinum (1,2).

Peripheral Complex Odontoma in the Gingiva: A Case Report of an 11 Year Old Boy and Review of Literature

According to the WHO histological classification of odontogenic tumours, odontomas originate from odontogenic epithelium and odontogenic ectomesenchyme, with or without hard tissue formation. They are generally classified into two types: complex and compound. Odontomas are usually intraosseous and often associated with delayed eruption of teeth. However, they can be extraosseous and are then referred to as either peripheral complex or compound odontoma. Peripheral odontomas are rare entities. We report a case of an 11 year old boy referred to the Department of Oral and Maxillofacial Surgery, Aarhus University Hospital by the boy’s dentist due to fibrous mass in the marginal gingiva in the anterior lower mandible. Removal of the mass revealed a peripheral complex odontoma and at the final 5-month postoperative inspection there was satisfying healing observed, a small, elevated, hyperplastic fibrous marginal gingiva.

小児の上顎洞内に進展した大きな複雑性歯牙腫の1例

Complex odontoma is classified as odontogenic epithelium with odontogenic ectomesenchyme with or without hard tissue formation according to the WHO histological classification of odontogenic tumors (2005). It rarely occurs in the maxillary sinus.

Ultrasound-guided fine needle aspiration cytology diagnosis of gall bladder lesions with application of WHO histological classification of tumors on cytoaspirate material

Introduction: Due to the increasing trend in gall bladder (GB) carcinoma in India, early diagnosis of GB lesion has become essential. Aim: It is to determine the accuracy of Ultrasonography (USG)-guided fine needle aspiration cytology (FNAC) and an attempt to classify the cytological material according to World Health Organization classification. Materials and Methods: This retrospective study for a span of 3 years was done in the Departments of Radiology and Pathology in Tertiary Teaching Hospital. US-guided FNAC of GB lesion and their histopathological finding were compared. Results: Sensitivity of US-guided FNAC was 98.6% and specificity 97.3%.

Lymph nodes metastases in thymic malignancies: we need prospective studies

Thymic epithelial tumors (TET) are rare malignancies of the anterior mediastinum with a wide spectrum of biologic behavior. It is generally accepted that thymomas become more invasive as their World Health Organization (WHO) histologic classification advances to B2 and B3.

Grading lung neuroendocrine tumors: Controversies in search of a solution.

Pathological grading of tumors is a way to measure biological aggressiveness. In lung neuroendocrine tumors (NET), grading is tautologically included into the current 2015 WHO histologic classification. Little is known, however, about alternative grading systems in lung NET. Through an extensive search of the English literature on lung NET (updated to April 2016), the following key questions were addressed: a) current concepts of grading; b) clinicians' requests for grading; c) functional parameters for grading; d) Ki-67 labeling index (LI) for grading; e) towards an effective pathology grading system. There is some room for inconsistency in the histologic classification of lung NET, likely due to the varying attribution of defining criteria. Innovative diffusion-weighted imaging upon magnetic resonance or molecular analysis could help separate indolent from aggressive lung NET, thus integrating a grading approach other than histology. Troubles in the clinical handling of metastatic or individual tumors when relying on morphology alone support the development of a lung-specific grading system for the more accurate prediction of prognosis and planning therapy in individual patients. To integrate the 2015 WHO classification using innovative grading based on Ki-67 LI, mitotic count and necrosis, a new proposal is emerging where three categories of lung NET are identified, namely Lu-NET G1, Lu-NET G2 and Lu-NET G3, which would allow tumors with similar behavior and therapy to be better handled according to their own biological potential. This new formulation of lung NET grading could have clinical relevance for the individual handling of patients.

Effect of World Health Organization (WHO) Histological Classification on Predicting Lymph Node Metastasis and Recurrence in Early Gastric Cancer.

BackgroundThe World Health Organization (WHO) histological classification for gastric cancer is widely accepted and used. However, its impact on predicting lymph node metastasis and recurrence in early gastric cancer (EGC) is not well studied.Material/MethodsFrom 1987 to 2005, 2873 EGC patients with known WHO histological type who had undergone curative resection were enrolled in this study. In all, 637 well-differentiated adenocarcinomas (WD), 802 moderately-differentiated adenocarcinomas (MD), 689 poorly-differentiated adenocarcinomas (PD), and 745 signet-ring cell adenocarcinomas (SRC) were identified.ResultsThe distribution of demographic and clinical features in early gastric cancer among WD, MD, PD, and SRC were significantly different. Lymph node metastasis was observed in 317 patients (11.0%), with the lymph node metastasis rate being 5.3%, 14.8%, 17.0%, and 6.3% in WD, MD, PD, and SRC, respectively. Univariate and multivariate analyses indicated that gender, tumor size, gross appearance, depth of invasion, and WHO classification were significantly associated with lymph node metastasis. Recurrence was observed in 83 patients (2.9%), with the recurrence rate being 2.2%, 4.5%, 3.0%, and 1.6% in WD, MD, PD, and SRC, respectively. Multivariate analysis confirmed that MD, elevated gross type, and lymph node metastasis were independent risk factors for recurrence in EGC. MD patients showed worse disease-free survival than non-MD patients (P=0.001).ConclusionsWHO classification is useful and necessary to evaluate during the perioperative management of EGC. Treatment strategies for EGC should be made prudently according to WHO classification, especially for MD patients.

Mise au point sur les classifications moléculaires et la nouvelle classification histologique du cancer de la vessie

Comment the new WHO histological classification of tumors of the urinary system and male genital organs 2016 and expose the state of art about urothelial carcinogenesis and molecular modifications of bladder cancer, with the consequences on the treatments. A systematic review of the literature search was performed from the data base PubMed, focused on the following keywords: "bladder cancer", "molecular", "subtypes". The new WHO histological classification of tumors of the urinary system 2016 confirm the importance of pathology in determining the care of patients, especially the grade, the histological type and the infiltration, while taking into account the difficulties. In 2014, the Cancer Genome Atlas reported genetic modifications of bladder cancer. Recently, several studies explored molecular anomalies of bladder cancer and elaborated molecular classifications, analyzing their predictive value. According to the groups, different molecular subtype had been defined: Urobasal A, Urobasal B, genomically unstable, infiltrated, squamous cell carcinoma-like and p53-like luminal bladder cancers. This latter subgroup seems to be chemoresistant. The molecular biology and classifications allow a better understanding of bladder cancer and could complete in near future histological data to improve patient management.