A Consensus Diagnosis Utilizing Surface KI-67 Expression as an Ancillary Marker in Low-Grade Dysplasia Helps Identify Patients at High Risk of Progression to High-Grade Dysplasia and Esophaegal Adenocarcinoma.

Esophageal adenocarcinoma (EAC) develops in a step-wise manner, from low-grade dysplasia (LGD) to high-grade dysplasia (HGD), and ultimately to invasive EAC. However, there remains diagnostic uncertainty about LGD and its risk of progression to HGD/EAC. The aim is to investigate the role of Ki-67, immune-histochemical marker of proliferation, surface expression in patients with confirmed LGD, and risk stratify progression to HGD/EAC.

Immunophenotypic differences between neoplastic and non-neoplastic androgen-producing cells containing and lacking Reinke crystals.

We performed a detailed morphologic, immunophenotypic, and endocrine characterization of neoplastic and non-neoplastic lesions of androgen-producing cells known to harbor or lack Reinke crystals (RCs) with an aim to provide further insight into the nature of these cells and crystals. Study cases were selected from the files of participating hospitals and subclassified according to current classifications: 20 with Leydig cell tumors (LCTs), 2 with testicular adrenal rest tumors (TARTs), 2 with testicular tumors of adrenogenital syndrome (TTAGS), and 2 with androgen insensitivity syndrome (AIS). An extensive immunophenotypic panel including markers used in sex cord-stromal cell tumors, androgen hormones, enzymes, and receptors was applied to the cases and 10 non-tumoral adrenal glands.

Gastric-type extremely well-differentiated adenocarcinoma arising in the blind pouch of a bypassed stomach, presenting as colonic pseudo-obstruction.

Gastric carcinoma after gastric bypass is rare. Extremely well-differentiated adenocarcinoma (EWDA) of the stomach is a rare variant that has been mostly reported in Japan. We present a case of a 68-year-old man with EWDA arising in the bypassed stomach that presented as a colonic pseudo-obstruction (CPO).

Nonmucinous cystadenomas of the pancreas with pancreatobiliary phenotype and ovarian-like stroma.

Among 31 benign cystic neoplasms of the pancreas diagnosed as mucinous cystadenomas, we identified 9 (29%) cases of nonmucinous cystadenomas with a pancreatobiliary phenotype and an ovarian-like stroma. Although both cystic tumors belong to the same family, they should be separated because their epithelial lining and cyst fluid are different. The lining cells of the nonmucinous cystadenomas consisted of a single layer of cuboidal cells, similar to the epithelial cells of the normal pancreatic ducts, and were not dysplastic (90%-100% of the lining cells).

Low Prevalence of TP53 Mutations and MDM2 Amplifications in Pediatric Rhabdomyosarcoma.

The tumor suppressor gene TP53 is the most commonly mutated gene in human cancer. The reported prevalence of mutations in rhabdomyosarcoma (RMS) varies widely, with recent larger studies suggesting that TP53 mutations in pediatric RMS may be extremely rare. Overexpression of MDM2 also attenuates p53 function.