Digital Whole Slide Imaging Compared With Light Microscopy for Primary Diagnosis in Surgical Pathology.

CONTEXT.­: The adoption of digital capture of pathology slides as whole slide images (WSI) for educational and research applications has proven utility. OBJECTIVE.­: To compare pathologists' primary diagnoses derived from WSI versus the standard microscope. Because WSIs differ in format and method of observation compared with the current standard glass slide microscopy, this study is critical to potential clinical adoption of digital pathology. DESIGN.­: The study enrolled a total of 2045 cases enriched for more difficult diagnostic categories and represented as 5849 slides were curated and provided for diagnosis by a team of 19 reading pathologists separately as WSI or as glass slides viewed by light microscope. Cases were reviewed by each pathologist in both modalities in randomized order with a minimum 31-day washout between modality reads for each case. Each diagnosis was compared with the original clinical reference diagnosis by an independent central adjudication review. RESULTS.­: The overall major discrepancy rates were 3.64% for WSI review and 3.20% for manual slide review diagnosis methods, a difference of 0.44% (95% CI, -0.15 to 1.03). The time to review a case averaged 5.20 minutes for WSI and 4.95 minutes for glass slides. There was no specific subset of diagnostic category that showed higher rates of modality-specific discrepancy, though some categories showed greater discrepancy than others in both modalities. CONCLUSIONS.­: WSIs are noninferior to traditional glass slides for primary diagnosis in anatomic pathology.

Two cases of concomitant acquired aplastic anemia and systemic mastocytosis.

Reactive bone marrow mast cells reliably lack the morphologic, immunophenotypic, and molecular features of systemic mastocytosis (SM). We report two unusual cases of acquired aplastic anemia (AA) in which multifocal aggregates of bone marrow mast cells fulfilled morphologic and immunophenotypic criteria for SM according to the World Health Organization 2008 classification. In the absence of clinical symptoms attributable to SM, the patients were treated with immunosuppressive therapy directed towards AA. Clinical follow-up and subsequent bone marrow examination revealed no evidence of overt SM in either patient. These cases represent, to our knowledge, the first reported instances in which criteria for SM have been fulfilled in the presence of AA. However, given the clinical courses followed by our patients, the incidental identification of mast cell lesions consistent with indolent SM may be of uncertain significance in the setting of AA.

Morphologic changes in explanted lungs after prostacyclin therapy for pulmonary hypertension.

Prostacyclin (PGI2) causes vasodilation and inhibition of platelet aggregation in vivo. PGI2 is also postulated to affect pulmonary vascular remodeling, at least partly through anti-proliferative effect via PGI2 receptor (PGIR). However, the mechanism(s) of action by which (PGI2) exerts its therapeutic effect is still not clear despite clear clinical benefit seen in severe pulmonary hypertension (PH) patients. We performed a histopathologic and morphometric study on the explanted lung tissues from PGI2-treated patients prior to lung transplantation (n = 9), in an attempt to elucidate morphologic changes associated with PGI2 treatment. Explanted lungs from PH patients without PGI2 treatment were examined as the control (n = 11). We also studied the possible differences in PGIR expression between the treated and untreated groups by immunohistochemical method. Seven out of 9 treated patients showed moderate to severe bronchial and perivascular inflammation, as opposed to only 1 such case in the control group. Five out of 9 treated cases showed moderate to severe alveolar edema with or without evidence of old hemorrhage, in contrast to only 1 case showing moderate alveolar edema in control patients. Morphometry did not reveal any significant difference between the two groups either in the % thickness of intima, media, or adventitia or in the density of plexiform lesions. Immunostain also failed to demonstrate any notable difference in PGIR expression. In conclusion, PGI2-treated cases revealed more pronounced pulmonary alveolar edema and inflammation, but no morphological evidence of altered vascular remodeling or PGIR expression after PGI2 therapy.

Clusterin expression in malignant lymphomas: a survey of 266 cases.

Clusterin expression has been reported to be characteristic of systemic anaplastic large cell lymphoma and usually negative in cutaneous anaplastic large cell lymphoma as well as other lymphoma types. We surveyed clusterin expression using immunohistochemical methods in 266 cases of non-Hodgkin's lymphoma and Hodgkin's disease to further assess the diagnostic utility of this marker. Clusterin immunostaining was observed in 40 of 49 (82%) systemic anaplastic large cell lymphomas and 12 of 29 (41%) cutaneous anaplastic large cell lymphomas. Clusterin also was expressed in 5 of 43 (12%) diffuse large B-cell lymphomas (4 of 5 CD30+), 1 of 14 (7%) peripheral T-cell lymphomas, 1 of 32 (3%) cases of nodular sclerosis Hodgkin's disease, and 1 case of mycosis fungoides in large cell transformation. Clusterin was negative in all other neoplasms assessed including follicular lymphoma of all grades (n = 24), mantle cell lymphoma (n = 13), marginal zone B-cell lymphoma (n = 12), precursor T-cell or B-cell lymphoblastic leukemia/lymphoma (n = 10), mixed cellularity Hodgkin's disease (n = 8), chronic lymphocytic leukemia/small lymphocytic lymphoma (n = 7), Burkitt lymphoma (n = 7), mycosis fungoides (n = 4), nodular lymphocyte predominant Hodgkin's disease (n = 3), lymphoplasmacytic lymphoma/Waldenstrom macroglobulinemia (n = 2), and plasmacytoma (n = 2). We conclude that clusterin is a marker of anaplastic large cell lymphoma and that addition of clusterin to antibody panels designed to distinguish systemic anaplastic large cell lymphoma from classical Hodgkin's disease is useful. However, clusterin is also positive in a substantial subset of cutaneous anaplastic large cell lymphomas, a smaller subset of diffuse large B-cell lymphomas, and rarely in cases of peripheral T-cell lymphoma and nodular sclerosis Hodgkin's disease.

Bidirectional (positive/negative) interference of spironolactone, canrenone, and potassium canrenoate on serum digoxin measurement: elimination of interference by measuring free digoxin or using a chemiluminescent assay for digoxin.

Spironolactone and potassium canrenoate (aldosterone antagonist diuretics) are often used with digoxin in clinical practice. Spironolactone, potassium canrenoate, and their common metabolite canrenone cross-react with the fluorescence polarization immunoassay (FPIA) for digoxin, and can falsely elevate serum digoxin concentrations. Serum digoxin concentrations were falsely lowered when the microparticle enzyme immunoassay (MEIA) was used. Aliquots of drug-free serum were supplemented with therapeutic and above-therapeutic concentrations of spironolactone, canrenone, and potassium canrenoate, and apparent digoxin activities were measured. We observed digoxin-like activities in the FPIA, but observed no activity with the MEIA or the chemiluminescent assay (CLIA). However, when serum digoxin pools prepared from patients receiving digoxin were supplemented with these compounds, we observed suppression of total digoxin levels with the MEIA. In contrast, no interference was observed in the presence of these compounds when CLIA was used for digoxin measurement. These compounds are strongly protein-bound, and no apparent digoxin activity was observed in the protein-free ultrafiltrate when drug-free sera were spiked with high levels of these compounds. Taking advantage of strong protein binding of these compounds and weak protein binding of digoxin (25%), interference of spironolactone, canrenone, and potassium canrenoate in FPIA and MEIA digoxin assays can be mostly eliminated by monitoring free digoxin concentration. Another approach to avoid this interference is to use the CLIA digoxin assay.