Sample Multiplexing: Increased Throughput for Quantification of Total Testosterone in Serum by Liquid Chromatography-Tandem Mass Spectrometry.

BACKGROUND: For high-volume assays, optimizing throughput reduces test cost and turn-around time. One approach for liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays is sample multiplexing, wherein the analyte of interest is derivatized in different specimens with reagents of different molecular weight (differential mass tagging). Specimens can then be combined and simultaneously analyzed within a single injection to improve throughput. Here we developed and validated a quantitative, sample-multiplexed LC-MS/MS assay for serum total testosterone (TT) based on this approach. METHODS: For the sample-multiplexed assay, calibrators, controls, and patient specimens were first extracted separately. After mass tagging with either methoxyamine or hydroxylamine, they were combined and injected into the LC-MS/MS system. To evaluate assay performance, we determined limit of quantification (LOQ), linearity, recovery, and imprecision. A method-comparison study was also performed, comparing the new assay with the standard LC-MS/MS assay in 1574 patient specimens. RESULTS: The method was linear from 2.5 to 2000 ng/dL, with accuracies from 93% to 104% for both derivatives. An LOQ of 1.0 ng/dL was achieved. Intra-assay and total CVs across 4 quality control concentrations were less than 10%. The assay demonstrated good agreement (Deming regression, 1.03x + 6.07) with the standard LC-MS/MS assay for the patient specimens tested (TT, 3 to 4862 ng/dL). CONCLUSION: Sample multiplexing by differential mass tagging of TT increases LC-MS/MS throughput 2-fold without compromising analytical accuracy and sensitivity.

Epstein - Barr virus association with plasma cell neoplasms.

AIMS: Epstein-Barr virus (EBV) expression has been reported in several hematopoietic and non-hematopoietic disorders but its expression in plasma cell neoplasms has been largely limited to immunodeficiency-related cases such as in the setting of post-organ transplantation or human immunodeficiency virus (HIV) infection. The aim of this study is to evaluate the association of EBV with plasma cell neoplasms, mainly in immunocompetent patients. METHODS AND RESULTS: We retrospectively studied 147 cases of patients with different plasma cell neoplasms (109 plasma cell myelomas, 22 plasmacytomas, and 16 monoclonal gammopathy cases). Six patients were immunocompromised. EBV was positive in 6 cases; 3 immunocompromised (2 patients with HIV infection and 1 patient was post-renal transplant) and 3 immunocompetent patients with plasmacytoma and variable plasmablastic features. CONCLUSIONS: Our data shows that EBV was negative in all plasma cell myeloma cases in immunocompetent patients and has an overall low association with the different plasma cell neoplasms in the immunocompetent setting. When expressed, it is usually associated with variable plasmablastic features.

Erratum to "Primary Desmoplastic Melanoma of the Penis".

[This corrects the article DOI: 10.1155/2015/706572.].

Primitive Spindle Cell Neoplasm of Ileum with Extensive Heterotopic Cartilage, Presenting as Acute Abdomen in a 6-Day-Old Neonate.

Neonatal intestinal masses with spindle cell morphology have broad differential diagnoses and require a multidisciplinary approach to make the final diagnosis. Spindle cell masses with heterotopic cartilage in the gastrointestinal tract are very rare, and, to our knowledge, have not previously been reported in the neonate. Here we present a case of intestinal primitive spindle cell neoplasm with extensive heterotopic cartilage that manifested initially as acute abdomen in a 6-day-old term infant. Plain radiography demonstrated pneumoperitoneum, prompting diagnostic laparotomy that identified a perforated mass involving the midileum. Histologic and immunohistochemical examination demonstrated an infiltrative spindle cell tumor most compatible with infantile fibrosarcoma (IFS) by a process of exclusion, with nodules of mature heterotopic cartilage. Additional staging studies did not reveal any evidence of residual or metastatic disease. Recognition of this rare variant of IFS will aid in differentiation from other neonatal intestinal mesenchymal tumors.

Primary Desmoplastic Melanoma of the Penis.

Desmoplastic melanomas are rare amelanotic melanomas that usually occur on skin with sun exposure. In this report, we present a 72-year-old man who presented with a desmoplastic melanoma of the penis. To our knowledge this represents the first reported case of primary desmoplastic melanoma of the penis. We discuss the pathologic differential and histologic evaluation.

BCR-PDGFRA fusion in a T lymphoblastic leukemia/lymphoma.

The BCR-PDGFRA fusion is a very rare event. To date, only eight cases of hematolymphoid neoplasms with the BCR-PDGFRA fusion gene have been reported. All cases except one had eosinophilia. We present the first case of T acute lymphoblastic leukemia with a t(4;22)(q12;q11.2) involving the BCR and PDGFRA genes, without associated eosinophilia. Radiology showed splenomegaly and extensive lymph node involvement. The patient rapidly achieved complete remission with treatment protocol for Philadelphia chromosome-negative acute lymphoblastic leukemia.

Pediatric renal solitary fibrous tumor: report of a rare case and review of the literature.

Solitary fibrous tumors (SFTs) are unusual spindle cell neoplasms initially described in the pleura but have since been discovered in many extrapleural locations. SFT of the kidney is extremely rare, the majority occurring in middle-aged adults. To date, only two pediatric cases of renal SFT have been reported. We report a case of large SFT in the kidney of a 3-year-old boy that was clinically and radiologically thought to be a nephroblastoma. This case is the first pediatric renal SFT to be reported with detailed histopathologic and cytogenetic analyses. SFT should be included in the differential diagnosis of pediatric renal tumors.

Thyroid-like follicular carcinoma of the kidney in a young patient with history of pediatric acute lymphoblastic leukemia.

Thyroid-like follicular carcinoma of the kidney (TLFCK) is a rare histological variant of renal cell carcinoma not currently included in the World Health Organization classification of renal tumors. Only 24 previous cases of TLFCK have been reported to date. We report a case of TLFCK in a 19-year-old woman with history of pediatric acute lymphoblastic leukemia. This patient is the youngest with TLFCK to be reported to date and the first with history of lymphoblastic leukemia. The development of TLFCK in a young patient with history of lymphoblastic leukemia is interesting and suggests that genes involved in leukemogenesis may also be important for TLFCK pathogenesis. Recognition of TLFCK is important to distinguish it from other conditions that show thyroid-like features, as a misdiagnosis can result in adverse patient care.

Cytopathologic, histopathologic, and immunohistochemical features of intrahepatic clear cell bile duct adenoma: a case report and review of the literature.

Intrahepatic clear cell bile duct adenoma is extremely rare, with only 3 previous cases reported in the literature. The cause of cytoplasmic clearing in clear cell bile duct adenoma has not been previously investigated. Distinguishing clear cell bile duct adenoma from other clear cell tumors, particularly clear cell cholangiocarcinoma, can be challenging. Previous studies have shown loss of CD10 expression and focal CD56 expression in cholangiocarcinoma. Expressions of CD10 and CD56 have not been previously studied in clear cell bile duct adenoma. A 37-year-old morbidly obese woman was diagnosed with a 2.8 cm intrahepatic clear cell bile duct adenoma following segmental hepatic resection. Histochemical analysis of the tumor suggested the cause of cytoplasmic clearing in the neoplastic cells to be mucin and not glycogen or lipid. On immunohistochemical staining, the neoplastic cells demonstrated staining for CK7, CA 19-9, polyclonal CEA, CD10 (apical), CD56 (focal), and vimentin. Ki-67 highlighted less than 2% of tumor cell nuclei. This is the first report to study the etiology of cell clearing in clear cell bile duct adenoma. Expression of CD10 in clear cell bile duct adenoma may help distinguish clear cell bile duct adenoma from clear cell cholangiocarcinoma.