Genomic characterisation of breast fibroepithelial lesions in an international cohort.

Fibroepithelial lesions (FELs) are a heterogeneous group of tumours comprising fibroadenomas (FAs) and phyllodes tumours (PTs). Here we used a 16-gene panel that was previously discovered to be implicated in pathogenesis and progression, to characterise a large international cohort of FELs via targeted sequencing. The study comprised 303 (38%) FAs and 493 (62%) PTs which were contributed by the International Fibroepithelial Consortium. There were 659 (83%) Asian and 109 (14%) non-Asian FELs, while the ethnicity of the rest was unknown. Genetic aberrations were significantly associated with increasing grade of PTs, and were detected more in PTs than FAs for MED12, TERT promoter, RARA, FLNA, SETD2, TP53, RB1, EGFR, and IGF1R. Most borderline and malignant PTs possessed ≥ 2 mutations, while there were more cases of FAs with ≤ 1 mutation compared to PTs. FELs with MED12 mutations had significantly higher rates of TERT promoter, RARA, SETD2, EGFR, ERBB4, MAP3K1, and IGF1R aberrations. However, FELs with wild-type MED12 were more likely to express TP53 and PIK3CA mutations. There were no significant differences observed between the mutational profiles of recurrent FAs, FAs with a history of subsequent ipsilateral recurrence or contralateral occurrence, and FAs without a history of subsequent events. We identified recurrent mutations which were more frequent in PTs than FAs, with borderline and malignant PTs harbouring cancer driver gene and multiple mutations. This study affirms the role of a set of genes in FELs, including its potential utility in classification based on mutational profiles. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Pericytoma With t(7;12): The First Ovarian Case Reported and a Review of the Literature.

We report the first case of an ovarian pericytoma with t(7;12). An 11-year-old child presented with abdominal pain and distension. A suprapubic mass was detected on examination and radiological investigations revealed a 16.5 cm solid-cystic ovarian mass. Histologically, the tumor was composed of spindle cells with S100-protein, Bcl-2, and CD10 reactivity on immunohistochemistry. Alpha fetoprotein, calretinin, alpha-inhibin, WT1, smooth muscle actin, caldesmon, desmin, cytokeratins, chromogranin, synaptophysin, EMA, Sox10, CD117, CD31, CD34, and CD68 were all negative. Molecular tests showed t(7;12)(p22;q13), resulting in the fusion of the ACTB with GLI1 genes and a diagnosis of pericytoma with t(7;12) of the ovary was made. We discuss the difficulties in diagnosing this lesion in the ovary and highlight the importance on molecular tests in characterizing challenging cases, especially primary ovarian spindle cell mesenchymal tumors.

Primary Bone Anaplastic Large Cell Lymphoma Masquerading as Ewing Sarcoma: Diagnosis by Anchored Multiplex PCR.

A 3-year-old boy presented with pathologic fracture of the left proximal femur. Magnetic resonance imaging revealed an aggressive expansile bony mass associated with cortical destruction and surrounding myositis. Computed tomography-guided biopsy revealed a monomorphic small round blue cell tumor by histology. CD99 immunoreactivity and low-level EWSR1 gene translocation by break-apart fluorescent in situ hybridization initially favored a diagnosis of Ewing sarcoma and chemotherapy commenced. Subsequent molecular evaluation by an anchored multiplex polymerase chain reaction-based assay (Archer FusionPlex Sarcoma Panel) revealed a nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) gene fusion. The diagnosis was then amended to primary bone ALK-positive anaplastic large cell lymphoma and the chemotherapy regimen was modified accordingly. This report illustrates the value of this molecular assay in establishing the correct diagnosis of a very rare malignancy masquerading as another tumor type.

The role of ischemia in necrotizing enterocolitis.

AIM: The role of ischemia in the pathogenesis of necrotizing enterocolitis (NEC) remains unclear. We used immunohistochemical markers of hypoxia to identify presence/absence of ischemia in NEC and spontaneous intestinal perforation (SIP) with clinical correlation. METHODS: Immunohistochemical staining was performed on 24 NEC and 13 SIP intestinal resection specimens using 2 hypoxia markers, hypoxia inducible factor 1α (HIF-1α) and glucose transporter 1 (GLUT1) and inflammatory markers, leukocyte common antigen (LCA) and myeloperoxidase. Ischemic score (0-6) from the sum of the HIF-1α and GLUT1 staining intensity grades was devised (positive ≥3). Inflammation was graded from the sum of LCA and myeloperoxidase grading. Relevant clinical information was obtained from hospital case records. RESULTS: Fourteen NEC specimens had positive ischemic score (4.6±1.2). The remaining 10 NEC (ischemic score 0.7±0.8) and all 13 SIP samples (ischemic score 0.5±0.5) were ischemic-negative. The ischemic-positive cases had classic NEC with multiple areas of bowel necrosis; were associated with later onset, enteral feeding and pneumatosis. In contrast, all ischemic-negative NEC were short-segment NEC with perforation. Their clinical profile was similar to the SIP cases with younger gestational age at birth, early onset, association with ibuprofen/indomethacin usage but not with feeding and pneumatosis. Ischemic scores are correlated with inflammation scores in mucosa but not submucosa. CONCLUSIONS: Ischemia as assessed with immunohistochemical markers HIF-1α and GLUT1, has a primary role in pathogenesis of classic NEC only, not in SIP or short-segment NEC with perforation. Better categorization of the different types of NEC can direct appropriate prevention and treatment strategies.

Thyroglossal duct cyst carcinoma: diagnostic and management considerations in a 15-year-old with a large submental mass.

A 15-year old boy presented with a 2-year history of a painless slowly enlarging submental neck mass. Head and neck imaging showed a multicystic mass with a central solid component that was closely applied to the hyoid bone. Core needle biopsy under general anaesthesia revealed a papillary thyroid neoplasm. The mass was resected and frozen section histology confirmed papillary carcinoma. Intraoperatively, enlarged cervical lymph nodes were palpable. Bilateral neck dissections and total thyroidectomy with parathyroid reimplantation were performed. On histological examination, the thyroid gland was not involved. The patient recovered uneventfully from the surgery and is planned for radioactive iodine therapy and thyroxine suppression, with subsequent follow-up with serum thyroid-stimulating hormone and thyroglobulin for surveillance. We review the literature and discuss challenges in the diagnosis and surgical management of this rare entity in the paediatric age group.