ERG Immunoreactivity in Blastic Hematolymphoid Neoplasms: Diagnostic Pitfall in the Workup of Undifferentiated Malignant Neoplasms.

Undifferentiated malignant neoplasms pose diagnostic challenges, and reliable immunohistochemical markers with well-characterized staining profiles are desirable when characterizing them. Our initial observation of erythroblast transformation specific regulated gene-1 (ERG) reactivity in myeloid sarcomas led us to broadly explore the utility of ERG as a marker of immature hematolymphoid neoplasms presenting in extramedullary sites. We stained 207 immature and mature hematolymphoid lesions as well as 39 benign hematolymphoid tissues and found weak-to-moderate ERG immunopositivity in 15 of 16 (94%) acute myeloid leukemias/myeloid sarcomas, including 4 of 5 (80%) CD34-negative/CD117-negative acute myeloid leukemias/myeloid sarcomas. ERG positivity was also seen in all 9 cases of B-lymphoblastic and T-lymphoblastic leukemia/lymphoma, all 3 cases of hematogone hyperplasia, and all 4 cases of systemic mastocytosis. ERG was negative in 148 mature B-cell and T-cell lymphomas, including 2 high-grade B-cell lymphomas and 2 blastoid variant mantle cell lymphomas; 23 histiocytic/dendritic cell neoplasms; 2 indolent T-lymphoblastic proliferations; and 2 blastic plasmacytoid dendritic cell neoplasms. We conclude that ERG immunoreactivity may pose a significant diagnostic pitfall in the workup of undifferentiated malignant neoplasms, particularly those presenting in extramedullary sites.

Human Germinal Center-associated Lymphoma (HGAL) Is a Reliable Marker of Normal and Neoplastic Follicular Helper T Cells Including Angioimmunoblastic T-Cell Lymphoma.

The diagnosis of angioimmunoblastic T-cell lymphoma (AITL) is complex and requires the demonstration of a T-follicular helper (TFH) phenotype. Immunophenotypic markers that detect the TFH phenotype are highly variable, thereby necessitating the use of 3 to 5 TFH markers to substantiate a TFH phenotype. We tested the utility of germinal center markers human germinal center-associated lymphoma (HGAL) and LIM-domain only 2 (LMO2) in detecting a TFH phenotype. We compared their staining to that of 6 TFH markers in current use, PD-1, ICOS, CXCL13, SAP, CD10, and BCL6, in a cohort of 23 AITL. Our results show that although both markers can detect a TFH phenotype, HGAL was superior to LMO2 in the percent of cells stained and the intensity of staining, 2 variables used to generate H-scores. Using H-scores as the metric, HGAL was most comparable to BCL6 among the currently used TFH markers and was more sensitive than CXCL13, SAP, CD10, and LMO2. PD-1 and ICOS emerged as the most robust of the 8 markers tested in this study in detecting a TFH phenotype. We conclude that HGAL is a reliable marker of TFH cells and can aid in the diagnosis of lymphomas of TFH derivation, particularly in the recognition of early patterns of AITL.

ALK-positive compound Spitz nevus with extensive perineural and intraneural neurotropism.

Historically recognized by their characteristic histopathologic features, Spitz neoplasms are now known to be molecularly defined by mutually exclusive recurrent abnormalities that cause activation of the MAPK pathway. Spitz neoplasms with ALK rearrangements frequently demonstrate polypoid growth with a plexiform arrangement of nested, fusiform melanocytes in intersecting fascicles. Although neurotropism has been described in indolent Spitz neoplasms, this feature is not frequently mentioned in publications on histopathologic assessment of this group of melanocytic tumors. Here, we present an unusual case of a 3-year-old female with an ALK-positive compound Spitz nevus with extensive perineural and intraneural neurotropism occurring on the vermilion border of the lower lip.

Making a Tissue Microarray.

Tissue microarray (TMA) is a widely used, high-throughput, cost-effective, and tissue and reagent-conserving method of performing molecular analysis. Multiple donor tissue cores are procured and transferred into a recipient TMA block for simultaneous differential and comparative molecular profiling under theoretically identical performance conditions. Described herein is a discussion of the theory behind the TMA, an overview of the concepts and principles of TMA design and construction, a brief summary of its advantages and disadvantages, and a sample protocol of TMA construction.

Biopsy-proven Hepatocellular Carcinoma in a 53-year-old Woman With Arginase Deficiency.

Arginase 1 deficiency, the least common urea cycle disorder, commonly presents with childhood-onset spastic paraplegia, progressive neurologic impairment, epilepsy, and developmental delay or regression. Biopsy-proven cirrhosis and hepatocellular carcinoma diagnosed via clinical and imaging studies (but without biopsy confirmation) have been previously reported. We report, herein, a case of a 53-year-old woman with arginase 1 deficiency who developed symptoms of "abdominal bloating." Imaging studies (ultrasound and magnetic resonance imaging) demonstrated 2 dominant hepatic masses, measuring 5.9 cm and 5.7 cm in greatest dimensions and located in hepatic segments 5 and 6, respectively. Core biopsies of the lesions demonstrated well-differentiated hepatocellular carcinoma. Immunohistochemistry performed on the segment 5 lesion was negative for arginase 1. This report represents, to the best of our knowledge, the first case of biopsy-proven hepatocellular carcinoma in an individual with arginase 1 deficiency.

Application of Immunohistochemistry in the Diagnosis of Pulmonary and Pleural Neoplasms.

CONTEXT: - A vast majority of neoplasms arising from lung or pleura are initially diagnosed based on the histologic evaluation of small transbronchial, endobronchial, or needle core biopsies. Although most diagnoses can be determined by morphology alone, immunohistochemistry can be a valuable diagnostic tool in the workup of problematic cases. OBJECTIVE: - To provide a practical approach in the interpretation and immunohistochemical selection of lung/pleura-based neoplasms obtained from small biopsy samples. DATA SOURCES: - A literature review of previously published articles and the personal experience of the authors were used in this review article. CONCLUSION: - Immunohistochemistry is a useful diagnostic tool in the workup of small biopsies from the lung and pleura sampled by small biopsy techniques.

Pediatric-type Follicular Lymphoma and Pediatric Nodal Marginal Zone Lymphoma: Recent Clinical, Morphologic, Immunophenotypic, and Genetic Insights.

Pediatric-type follicular lymphoma and pediatric nodal marginal zone lymphoma are 2 of the rarest B-cell lymphomas. Although they are both predominantly seen in children, they can manifest in the adult population as well. Our understanding of these lymphomas has advanced rapidly in recent years such that we not only have a firm grasp of the morphologic and immunophenotypic findings, but also have a deeper insight into critical genetic and molecular pathways of these diseases. This review will cover the clinical and pathologic characteristics, treatment, prognosis, and important differential diagnoses of these entities.

An unusual cause of altered mental status: the importance of monitoring a patient's blood pressure.

A 73-year-old man presented to the emergency room for acute onset altered mental status. The initial work-up yielded no definitive cause. An MRI demonstrated lesions in the bilateral posterior occipital lobes (not noted on an earlier MRI obtained from an outside institution) that were suggestive of posterior reversible encephalopathy syndrome (PRES). He had a history of Parkinson's disease complicated by autonomic instability (wide blood pressure fluctuations) that was medically controlled in the outpatient setting. During the early course of his hospitalisation, he again displayed wide blood pressure fluctuations. After his blood pressure stabilised, his mental status eventually improved to baseline. A repeat MRI obtained demonstrated near-complete resolution of the previously noted lesions and confirmed the diagnosis of PRES.

Robotic-assisted Roux-en-Y gastric bypass performed in a community hospital setting: the future of bariatric surgery?

INTRODUCTION: Since receiving Food and Drug Administration approval in 2000, surgery utilizing a robot has been successfully performed in numerous procedures including gastric bypass. However, despite the proven safety profile, reported lower complication rates, and technical benefits of robotic surgery, only a few centers in the USA have consistently applied this technology to bariatric surgery. In addition, there are limited studies with relatively small sample sizes comparing robotic-assisted Roux-en-Y gastric bypass (RRYGB) with laparoscopic Roux-en-Y gastric bypass (LRYGB). METHODS: Through a retrospective analysis of our database, we compared outcomes of RRYGB versus LRYGB in the treatment of morbid obesity. All patients who underwent RRYGB and LRYGB through the Comprehensive Weight Management Program of the Queen's Medical Center (Honolulu, HI) from January 2007 to December 2009 were included. Outcomes data included weight loss, operative times, and hospital length of stay. All complications were reported. RESULTS: 105 patients who underwent RRYGB were compared with 195 patients who received LRYGB. Excess weight loss, estimated blood loss, and length of hospital stay were similar in both groups. There were no mortalities in either group. The RRYGB group experienced a 9.5% complication rate versus 9.7% in LRYGB patients. Operative time was the only statistically significant difference, being approximately 17 min in favor of LRYGB. However, there was a steady decrease in RRYGB operative time with increasing experience. CONCLUSION: Our study demonstrates a favorable safety profile with nearly equivalent outcomes and some previously unidentified qualitative benefits of the RRYGB approach to bariatric surgery in a community setting. These results are despite our early experience with the robotic surgery platform and confirm noninferiority of RRYGB versus LRYGB. While the RRYGB operative time was longer than LRYGB, the demonstrated decrease in operative time commensurate with increase in operative experience holds tremendous promise for the future.

A "silent culture-negative" abdominal aortic mycotic aneurysm: Rapid detection of Bartonella species using PCR and high-throughput mass spectrometry.

A gram-negative, rod-shaped microorganism was detected in a 69-year-old man suffering from chronic back pain but otherwise exhibiting no signs of infection. The bacterium could not be identified using any routine diagnostic modality. A research use only application utilizing PCR and Mass Spectrometry was performed on nucleic acid extracted from the tissue sample. These studies resulted in the implication of Bartonella quintana as the underlying cause of the infection. B. quintana is not a well-known cause of an abdominal aortic mycotic aneurysm. This article will discuss the B. quintana infection, its diagnosis and treatment, and reinforce the potential of B. quintana as a possible etiology in mycotic aneurysms that show no apparent indications of infection. It will also explore the potential use of polymerase chain reaction detected by electrospray ionization mass spectrometry (PCR/ESI-MS) to help identify B. quintana in a situation where other conventional methods prove non-informative.