Uncommon invasive lobular carcinoma with papillary architecture-clinicopathologic and molecular characterization with review of the literature.

Breast cancer is the most common malignancy in woman, and its associated mortality is still rising worldwide. Among all the different subtypes of breast cancer, invasive lobular carcinoma (ILC) is the second most frequent. Several histological variants of ILC currently exist such as solid, alveolar, pleomorphic, tubulo-lobular, and mixed types. Recently, a new variant of ILC with a papillary growth pattern has been described. Here, we make a review of the literature and report the sixth case of a woman suffering from this very uncommon variant. Of note, she had a concomitant axillary lymph node metastasis, a manifestation not yet described so far. Molecular analysis showed CDH1 and PIK3CA mutations, along with similar quantitative chromosomal alterations in both primary and metastasis. Because ILC and papillary carcinoma are managed differently, our aim here is to raise awareness among the pathologists to avoid misdiagnosis of this unusual variant and subsequent inappropriate treatment.

Diagnostic Challenges and Pitfalls of Mammary Pleomorphic Adenoma Illustrated by a Case Report.

Mammary pleomorphic adenoma is a biphasic tumor, characterized by epithelial-myoepithelial components with myxochondroid stroma, resembling the prototypic pleomorphic adenoma of the salivary glands. We report the multiple diagnostic pitfalls raised by a mammary pleomorphic adenoma, initially diagnosed as mucinous carcinoma on fine-needle aspiration (FNA) cytology and invasive carcinoma on needle core biopsy. The final diagnosis was made on the surgical specimen. As the term "pleomorphic" suggests, this tumor can present various phenotypes, some of which might be misleading on both FNA cytology or needle core biopsy. Rearrangements in PLAG1 and HMGA2 genes have not been detected in our patient. Mammary pleomorphic adenoma is considered a benign tumor, despite rare local recurrence and malignant behavior. Its correct identification, despite the difficulties, is essential to avoid unnecessary aggressive treatment.

Phenotypic discordance between primary and metastatic breast cancer in the large-scale real-life multicenter French ESME cohort.

Expression of hormone receptor (HR) for estrogens (ER) and progesterone (PR) and HER2 remains the cornerstone to define the therapeutic strategy for breast cancer patients. We aimed to compare phenotypic profiles between matched primary and metastatic breast cancer (MBC) in the ESME database, a National real-life multicenter cohort of MBC patients. Patients with results available on both primary tumour and metastatic disease within 6 months of MBC diagnosis and before any tumour progression were eligible for the main analysis. Among the 16,703 patients included in the database, 1677 (10.0%) had available biopsy results at MBC diagnosis and on matched primary tumour. The change rate of either HR or HER2 was 27.0%. Global HR status changed (from positive = either ER or PR positive, to negative = both negative; and reverse) in 14.2% of the cases (expression loss in 72.5% and gain in 27.5%). HER2 status changed in 7.8% (amplification loss in 45.2%). The discordance rate appeared similar across different biopsy sites. Metastasis to bone, HER2+ and RH+/HER2- subtypes and previous adjuvant endocrine therapy, but not relapse interval were associated with an HR discordance in multivariable analysis. Loss of HR status was significantly associated with a risk of death (HR adjusted = 1.51, p = 0.002) while gain of HR and HER2 discordance was not. In conclusion, discordance of HR and HER2 expression between primary and metastatic breast cancer cannot be neglected. In addition, HR loss is associated with worse survival. Sampling metastatic sites is essential for treatment adjustment.

Multifocal in situ mantle cell neoplasia of the ileocecal region: a case report with simultaneous nodal and extranodal involvement.

In situ mantle cell neoplasia (ISMCN) is a rare entity of disputed clinical significance. We report an additional case, unusual by its presentation in the large intestine and its multifocal involvement of several nodal and extranodal sites. The diagnosis was made in a 46-year-old male patient from a surgical specimen resected for cecal adenocarcinoma. Gross examination showed multiple small polypoid lesions surrounding the ileocecal valve, corresponding to lymphoid aggregates with hyperplastic follicles. Numerous cyclin D1/SOX11+ lymphoid cells, harboring the t(11;14)(q13;q32) translocation, were present in the inner layers of mantle zones. The same lesions were found in the ileum, the appendix, and the regional lymph nodes. The final diagnosis was multifocal ISMCN of the ileocecal region, with both nodal and extra-nodal involvement. A simple surveillance was decided. Our observation expands the clinical spectrum of the disease and underlines the necessity to closely examine even normal-appearing reactive lymphoid tissues.

Prospective Multicenter Study Validate a Prediction Model for Surgery Uptake Among Women with Atypical Breast Lesions.

BACKGROUND: Diagnosis of atypical breast lesions (ABLs) leads to unnecessary surgery in 75-90% of women. We have previously developed a model including age, complete radiological target excision after biopsy, and focus size that predicts the probability of cancer at surgery. The present study aimed to validate this model in a prospective multicenter setting. - METHODS: Women with a recently diagnosed ABL on image-guided biopsy were recruited in 18 centers, before wire-guided localized excisional lumpectomy. Primary outcome was the negative predictive value (NPV) of the model. RESULTS: The NOMAT model could be used in 287 of the 300 patients included (195 with ADH). At surgery, 12 invasive (all grade 1), and 43 in situ carcinomas were identified (all ABL: 55/287, 19%; ADH only: 49/195, 25%). The area under the receiving operating characteristics curve of the model was 0.64 (95% CI 0.58-0.69) for all ABL, and 0.63 for ADH only (95% CI 0.56-0.70). For the pre-specified threshold of 20% predicted probability of cancer, NPV was 82% (77-87%) for all ABL, and 77% (95% CI 71-83%) for patients with ADH. At a 10% threshold, NPV was 89% (84-94%) for all ABL, and 85% (95% CI 78--92%) for the ADH. At this threshold, 58% of the whole ABL population (and 54% of ADH patients) could have avoided surgery with only 2 missed invasive cancers. CONCLUSION: The NOMAT model could be useful to avoid unnecessary surgery among women with ABL, including for patients with ADH. CLINICAL TRIAL REGISTRATION: NCT02523612.

[Gastric bacterial overgrowth: An unusual histological observation, not to be overlooked]. / Pullulation bactérienne gastrique : une observation histologique inhabituelle, à ne pas méconnaître.

Gastric bacterial overgrowth is a rare situation, which may be associated with short- and long-term complications. It must be known from pathologists, since it might be detected incidentally at histological examination of gastric biopsies. We report here the case of a 74-year old woman, obese, without significant medical history, apart from a gastro-esophageal reflux treated by the long-term administration of proton pump inhibitors (PPI). In this patient, gastric bacterial overgrowth was detected at histological examination of gastric biopsies performed after colectomy for left colon adenocarcinoma. Large clusters of small, round, "coccoid" bacteria were present in the gastric mucus. Their characteristics were suggestive of enterobacteria. Bacterial proliferation was associated with severe and diffuse lesions of active gastritis. The course was rapidly unfavorable, and the patient rapidly deceased with multiple infections and multi-organ failure. In our observation, the pathogenesis of gastric bacterial overgrowth was probably multifactorial. It might have been facilitated by long-term PPI treatment and obesity, which are known risk factors, and promoted, in the post-operative setting, by multiple infections and immune failure. Our observation underlines that gastric bacterial overgrowth might be associated with severe gastritis, which might justify antibiotherapy. Other consequences of prolonged gastric dysbiosis cannot be excluded, such as the promotion of neoplastic lesions.

Gastrointestinal stromal tumors (GIST) presenting in the liver: Diagnostic, prognostic and therapeutic issues.

CONTEXT: Extra-gastrointestinal stromal tumors (E-GIST) presenting in the liver are exceedingly rare and raise difficult diagnostic and therapeutic challenges. METHODS: We report on two cases of liver E-GIST with different clinical presentations. We describe their clinical and imaging features, their histopathological and molecular characteristics, their treatment and their course. RESULTS: The first case was that of a 56-year-old male presenting with a 10-cm liver mass; the initial diagnosis, made in 1986 from a biopsy sample, was leiomyosarcoma; liver transplantation was performed in 1987; no extra-hepatic tumor was found; the course was uneventful until 1999, when tumor recurrence was diagnosed along the initial biopsy route; after reevaluation of available material, the definitive pathological diagnosis was GIST; imatinib treatment resulted in major response; the patient died of end-stage kidney disease 22 years after the initial diagnosis and 9 years after tumor recurrence. The second case is that of a 59-year-old female presenting with a 23-cm abdominal mass connected to the liver; on biopsy, the tumor was diagnosed as epithelioid GIST with exon 11 KIT mutation; imatinib treatment resulted in stable disease. CONCLUSIONS: The diagnosis of E-GIST must be for any sarcoma presenting in the liver and confirmed by immunohistochemical and molecular techniques. Treatment might require aggressive strategies, which can be successful despite apparently adverse histoprognostic factors.

[Evaluation of tumor-infiltrating lymphocytes in breast cancer: How to use the 2014 international guidelines?] / Évaluation des lymphocytes infiltrant la tumeur dans les cancers du sein : comment appliquer les recommandations internationales 2014 ?

With the major development of immunotherapies, evaluation of the immune response associated to cancer has become the new challenge for pathologists. In breast cancer, this perspective has been notably anticipated by the recent publication, in 2014, of international guidelines for assessment of tumor-infiltrating lymphocytes (TILs), on routine haematoxylin-eosin stains. This technical article aims at reviewing the main key points and different steps in evaluation of tumor-infiltrating lymphocytes, in order to allow an easy implementation of this putative biomarker in routine practice. Widespread diffusion of international guidelines is the key to development of a standardized and reproducible biomarker. This early learning phase is of particular importance, as immune response will probably play a major role as a prognostic and predictive biomarker, especially in triple-negative and HER2 positive breast cancer.