Reticulohistiocytoma and Reticulohistiocytosis Jacob R. Bledsoe Louis P. Dehner Rosalynn M. Nazarian DEFINITION Reticulohistiocytoma (RH) (solitary epithelioid histiocytoma) is a rare cutaneous histiocytic proliferation of unknown etiology that typically presents…
Non-Langerhans Cell Histiocytoses Andrea P. Moy Louis P. Dehner Rosalynn M. Nazarian JUVENILE AND ADULT XANTHOGRANULOMA Introduction Juvenile and adult xanthogranuloma are benign proliferations of non-Langerhans histiocytes. The juvenile xanthogranuloma…
Rosai–Dorfman Disease Joseph R. Kallini M. Yadira Hurley DEFINITION Rosai–Dorfman disease (RDD), also referred to as Destombes–Rosai–Dorfman syndrome, is a benign proliferative disorder of histiocytes. It is also termed sinus…
Benign and Malignant Langerhans Cell Proliferations Jacob R. Bledsoe Louis P. Dehner Rosalynn M. Nazarian DEFINITION Langerhans cell histiocytosis (LCH) is a clinically heterogeneous disorder characterized by a clonal proliferation…
Mast Cell Neoplasms Jonathan J. Davick Catherine G. Chung Liaqat Ali MASTOCYTOMA Definition A form of cutaneous mastocytosis characterized by the presence of one or a few solitary cutaneous tumors…
Methods of Safe Handling of Radionuclides and Pertaining Rules and Regulations Any use of radionuclides is fraught with the danger of inadvertently exposing an individual to radiation, and therefore to…
Schnitzler Syndrome Viktoryia Kazlouskaya Jacqueline M. Junkins-Hopkins INTRODUCTION Schnitzler syndrome (SchS) is a rare and often underreported chronic multisystem disorder, diagnosed on the basis of the presence of two major…
Biologic Effects of Radiation and Risk Evaluation from Radiation Exposure Interaction of radiation with biologic systems results in a variety of biologic changes that can be either deleterious or benign….
Pyoderma Gangrenosum Campbell L. Stewart Roberto Novoa DEFINITION Pyoderma gangrenosum (PG) is a rare, ulcerative cutaneous disease of unknown etiology. Its diagnosis critically relies upon the exclusion of other causes…
Detectability or Final Contrast in an Image An imaging devise should ideally detect the smallest possible localized or focal abnormalities (lesions) that may be present in an organ. Because of…
