Expression of the neural stem cell markers NG2 and L1 in human angiomyolipoma: are angiomyolipomas neoplasms of stem cells?

Angiomyolipomas are benign tumors of the kidney which express phenotypes of smooth muscle, fat, and melanocytes. These tumors appear with increased frequency in the autosomal dominant disorder tuberous sclerosis and are the leading cause of morbidity in adults with tuberous sclerosis. While benign, these tumors are capable of provoking life threatening hemorrhage and replacement of the kidney parenchyma, resulting in renal failure. The histogenesis of these tumors is currently unclear, although currently, we believe these tumors arise from perivascular epithelioid cells of which no normal counterpart has been convincingly demonstrated. Recently, stem cell precursors have been recognized that can give rise to smooth muscle and melanocytes. These precursors have been shown to express the neural stem cell marker NG2 and L1. In order to determine whether angiomyolipomas, which exhibit smooth muscle and melanocytic phenotypes, express NG2 and L1, we performed immunocytochemistry on a cell line derived from a human angiomyolipoma, and found that these cells are uniformly positive. Immunohistochemistry of human angiomyolipoma specimens revealed uniform staining of tumor cells, while renal cell carcinomas revealed positivity only of angiogenic vessels. These results support a novel histogenesis of angiomyolipoma as a defect in differentiation of stem cell precursors

Preoperative RAS Mutational Analysis Is of Great Value in Predicting Follicular Variant of Papillary Thyroid Carcinoma

Follicular variant of papillary thyroid carcinoma (FVPTC), particularly the encapsulated subtype, often causes a diagnostic dilemma. We reconfirmed the molecular profiles in a large number of FVPTCs and investigated the efficacy of the preoperative mutational analysis in indeterminate thyroid nodules. BRAF V600E/K601E and RAS mutational analysis was performed on 187 FVPTCs. Of these, 132 (70.6%) had a point mutation in one of the BRAF V600E ( = 57), BRAF K601E ( = 11), or RAS ( = 64) genes. All mutations were mutually exclusive. The most common RAS mutations were at NRAS codon 61. FNA aspirates from 564 indeterminate nodules were prospectively tested for BRAF and RAS mutation and the surgical outcome was correlated with the mutational status. Fifty-seven and 47 cases were positive for BRAF and RAS mutation, respectively. Twenty-seven RAS-positive patients underwent surgery and all except one patient had FVPTC. The PPV and accuracy of RAS mutational analysis for predicting FVPTC were 96% and 84%, respectively. BRAF or RAS mutations were present in more than two-thirds of FVPTCs and these were mutually exclusive. BRAF mutational analysis followed by N, H, and KRAS codon 61 mutational analysis in indeterminate thyroid nodules would streamline the management of patients with malignancies, mostly FVPTC

Infectious aneurysmal rupture presenting as massive intracerebral hemorrhage in a preterm baby

INTRODUCTION: Infectious intracranial aneurysms in infantile period are very rare, and there is no report of infectious intracranial aneurysm in preterm infant CASE REPORT: A 43-day-old female infant, delivered at 29 weeks of gestation, presented with massive intracranial hemorrhage. Eighteen days after diagnoses of necrotizing enterocolitis, sepsis, and meningitis, the baby became lethargic with rigid left limbs. Imaging studies revealed a large hematoma in the right temporoparietal region and adjacent lateral ventricle. During removal of fresh hematoma, an actively bleeding nodular mass, contiguous with the distal middle cerebral artery branch, was found and excised from the parent vessel. Pathologic examination revealed a ruptured infectious intracranial aneurysm. After surgery, her neurologic status improved and she was doing well at 12 months' follow-up with mild spastic hemiparesis. CONCLUSION: To our knowledge, this is the first reported case of infectious intracranial aneurysm in the preterm infant, which was successfully treated with hematoma evacuation and resection of the aneurysm

Development of an Ammonium Sulfate DNA Extraction Method for Obtaining Amplifiable DNA in a Small Number of Cells and Its Application to Clinical Specimens

DNA extraction from microdissected cells has become essential for handling clinical specimens with advances in molecular pathology. Conventional methods have limitations for extracting amplifiable DNA from specimens containing a small number of cells. We developed an ammonium sulfate DNA extraction method (A) and compared it with two other methods (B and C). DNA quality and quantity, β-globin amplification, and detectability of two cancer associated gene mutations were evaluated. Method A showed the best DNA yield, particularly when the cell number was very low. Amplification of the β-globin gene using DNA from the SNU 790 cell line and papillary thyroid carcinoma (PTC) cells extracted with Method A demonstrated the strongest band. BRAFV600E mutation analysis using ethanol-fixed PTC cells from a patient demonstrated both a “T” peak increase and an adjacent “A” peak decrease when 25 and 50 cells were extracted, whereas mutant peaks were too low to be analyzed using the other two methods. EGFR mutation analysis using formalin-fixed paraffin-embedded lung cancer tissues demonstrated a mutant peak with Method A, whereas the mutant peak was undetectable with Methods B or C. Method A yielded the best DNA quantity and quality with outstanding efficiency, particularly when paucicellular specimens were used

Comprehensive histologic analysis of interstitial lipolysis with the 1444 nm wavelength during a 3-month follow-up

A number of near-infrared wavelengths have been proposed and studied for laser lipolysis, but the histologic evaluation of tissue response to laser lipolysis during long-term follow-up has been lacking. A 1444 nm Nd:YAG laser with better absorption in both fat and water has recently attracted attention. The present study was designed to investigate the comprehensive histopathology of 1444 nm Nd:YAG laser-assisted lipolysis at different energy levels during a 3-month follow-up. Laser lipolysis was performed on porcine fat tissue in vivo using a 1444 nm Nd:YAG laser (AccuSculpt®, Lutronic Corporation, Ilsan, Republic of Korea) and the total energies delivered interstitially to 10x10 cm2 areas were 750 J, 1500 J, 2250 J, 3000 J, 3750 J, 4500 J, and 5250 J. Biopsy samples were taken and histologically analyzed immediately after biopsy and at 1, 2, 4, and 12 weeks postoperatively. With a fluence setting above 3000J/100 cm2, inflammation was severe and remained by the 3-month follow-up, resulting in severe scarring of the fat tissue. Below this energy level, mild lobular inflammation in the early phase biopsy had resolved with no scarring by the 3-month follow-up. No histologic changes in the epidermis or dermal connective tissue were present. This study suggested that controlling the energy level is important for clinical applications of laser lipolysis with no significant complications