Echinococcus multilocularis: Diagnostic problem in a liver core biopsy.

Echinococcus multilocularis causes an aggressive form of hydatidosis whose histomorphological picture is generally not well recognized. We report a case of 39-year-old women presenting with poorly circumscribed nodules in the right hepatic lobe. Owing to the clinical suspicion of focal nodular hyperplasia and hepatocellular adenoma, a core biopsy was performed. The histological findings of necrotic fibrous tissue infiltrated by narrow epithelial cords and small cysts containing cytokeratin positive material were in concordance with the diagnosis of cholangiocarcinoma. Subsequent examination of the surgically resected necrotic nodules with a vital tissue at the periphery corresponded to a reparative fibrosis accompanied by a striking ductular proliferation. Serological and molecular genetic work-up led to the diagnosis of Echinococcus multilocularis. The aim of this report is to point out the unusual histological features of the solid foci of alveolar hydatidosis, which consisted of necrotic fibrous tissue with ductular reaction. Such findings in a core biopsy may simulate regressively altered carcinoma.

"High-grade oncocytic renal tumor": morphologic, immunohistochemical, and molecular genetic study of 14 cases.

The spectrum of the renal oncocytic tumors has been expanded in recent years to include several novel and emerging entities. We describe a cohort of novel, hitherto unrecognized and morphologically distinct high-grade oncocytic tumors (HOT), currently diagnosed as "unclassified" in the WHO classification. We identified 14 HOT by searching multiple institutional archives. Morphologic, immunohistochemical (IHC), molecular genetic, and molecular karyotyping studies were performed to investigate these tumors. The patients included 3 men and 11 women, with age range from 25 to 73 years (median 50, mean 49 years). Tumor size ranged from 1.5 to 7.0 cm in the greatest dimension (median 3, mean 3.4 cm). The tumors were all pT1 stage. Microscopically, they showed nested to solid growth, and focal tubulocystic architecture. The neoplastic cells were uniform with voluminous oncocytic cytoplasm. Prominent intracytoplasmic vacuoles were frequently seen, but no irregular (raisinoid) nuclei or perinuclear halos were present. All tumors demonstrated prominent nucleoli (WHO/ISUP grade 3 equivalent). Nine of 14 cases were positive for CD117 and cytokeratin (CK) 7 was either negative or only focally positive in of 6/14 cases. All tumors were positive for AE1-AE3, CK18, PAX 8, antimitochondrial antigen, and SDHB. Cathepsin K was positive in 13/14 cases and CD10 was positive in 12/13 cases. All cases were negative for TFE3, HMB45, Melan-A. No TFEB and TFE3 genes rearrangement was found in analyzable cases. By array CGH, complete chromosomal losses or gains were not found in any of the cases, and 3/9 cases showed absence of any abnormalities. Chromosomal losses were detected on chromosome 19 (4/9), 3 with losses of the short arm (p) and 1 with losses of both arms (p and q). Loss of chromosome 1 was found in 3/9 cases; gain of 5q was found in 1/9 cases. On molecular karyotyping, 3/3 evaluated cases showed loss of heterozygosity (LOH) on 16p11.2-11.1 and 2/3 cases showed LOH at 7q31.31. Copy number (CN) losses were found at 7q11.21 (3/3), Xp11.21 (3/3), Xp11.22-11.21 (3/3), and Xq24-25 (2/3). CN gains were found at 13q34 (2/3). Ten patients with available follow up information were alive and without disease progression, after a mean follow-up of 28 months (1 to 112 months). HOT is a tumor with unique morphology and its IHC profile appears mostly consistent. HOT should be considered as an emerging renal entity because it does not meet the diagnostic criteria for other recognized eosinophilic renal tumors, such as oncocytoma, chromophobe renal cell carcinoma (RCC), TFE3 and TFEB RCC, SDH-deficient RCC, and eosinophilic solid and cystic RCC.

CD44 as a cancer stem cell marker and its prognostic value in patients with ovarian carcinoma.

The aim of our study was to clarify whether the CD44 adhesion molecule as a cancer stem cell marker could also serve as a prognostic factor in patients with epithelial ovarian cancer (EOC). A retrospective study was performed on 87 patients with histologically verified EOC. Specimens of both primary tumour and implantation metastases were tested from 48 of them. CD44 expression was detected by immunohistochemistry. We looked for the cut-off levels of CD44 expression using the Cox regression model. We confirmed statistically significant prognostic factors for overall survival (OS) and disease-free interval (DFI) to be: stage of the disease, postoperative residual tumour and papillary serous histological type. We demonstrated a statistically significant correlation between low CD44 expression and serous papillary carcinoma histotype, tumour recurrence and chemoresistance at a value below 2%. CD44 was neither a prognostic factor of OS nor of DFI. IMPACT STATEMENT What is already known about this subject: Epithelial ovarian cancer is the second most common gynaecological cancer in developed countries. Despite great efforts devoted to ovarian cancer research during past decades, levels of patient mortality have changed very little. Cancer stem cells (CSCs) are subpopulations of cells with typical characteristics of stem cells - i.e. the ability to self-renew and differentiate in a variety of cell types. The main surface marker typical for CSCs is CD44. The aim of our study was to clarify whether the CD44 as a CSCs marker could serve as a prognostic factor in patients with epithelial ovarian cancer. Previous studies published on this topic revealed controversial results. The novelty of our study lies in looking for the cut-off using the Cox regression model. WHAT THIS STUDY ADDS: We demonstrated a statistically significant correlation between low CD44 expression and serous papillary carcinoma histotype, tumour recurrence and chemoresistance at a value below 2%, however, CD44 was neither a prognostic factor of overall survival nor of disease-free interval. We propose to investigate other markers including other CSCs as a prognostic factors or potential aims for targeted therapy in ovarian cancer.