Bias and Causal Associations in Observational Research
Chapter Contents Internal and External Validity 26 Bias 26 Selection Bias 27 Are the Groups Similar in all Important Respects? 27 Information Bias 28 Has Information Been Gathered in the…
Descriptive Studies: What They Can and Cannot Do
Chapter Contents The Descriptive Triad—Or Pentad? 14 Five ‘W’ Questions 14 Types of Descriptive Studies 15 Case Report 16 Case-Series Report 16 Cross-Sectional (Prevalence) Studies 16 Surveillance 17 Ecological Correlational…
An Overview of Clinical Research: The Lay of the Land
Chapter Contents A Taxonomy of Clinical Research 2 What Studies Can and Cannot Do 4 Descriptive Study 4 Cross-Sectional Study: A Snapshot in Time 4 Cohort Study: Looking Forward in…
Tumors of neuroectodermal origin
Reactive lesions Traumatic Neuroma Definition • A reactive/reparative process characterized by proliferation of axons, Schwann cells, and perineurial fibroblasts in a disorganized pattern in the background of collagenous stroma (scar)…
Tumors of vascular origin
Benign tumors including reactive vascular proliferations and ectasias Intravascular Papillary Endothelial Hyperplasia (Masson tumor) Definition • A nonneoplastic, reactive, endothelial proliferation representing an organizing thrombus, characterized by formation of arborizing…
Miscellaneous Tumors of Uncertain Differentiation
Benign tumors Superficial Angiomyxoma Definition • An uncommon distinct type of myxoma characterized by the presence of thin-walled blood vessels • This is likely to represent the same entity as…
Pericytic (perivascular) tumors
Benign tumors Glomus Tumor Definition • A benign tumor composed of modified smooth muscle cells (e.g., glomus cells) • Subclassified into three groups based on the proportions of glomus cells,…
Bone- and cartilage-forming tumors and tumors of joints
Benign tumors and reactive proliferations Osteoma Cutis Definition • Osteoma cutis represents a reactive, metaplastic, lamellar bone formation in the dermis and/or subcutis • Primary and secondary forms of osteoma…
Adipocytic tumors
Benign tumors and reactive conditions Lipoma Definition • A benign dermal or subcutaneous mesenchymal tumor composed of mature adult-type adipose tissue Clinical features Epidemiology • The most commonly encountered mesenchymal…
Fibrohistiocytic tumors
Benign tumors Fibrous Papule Definition • A benign proliferation in the superficial dermis, composed of fibroblasts, blood vessels, and sparse inflammatory cell infiltrate in the background of a sclerotic dermal…
