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Principles and limitations of histologic diagnosis. Standard parameters of diagnosis Pattern recognition Resemblance to normal histology Cost and availability Adult vs. pediatric tumors. Principles and limitations of histologic diagnosis. Standard parameters of diagnosis.
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Principles and limitations of histologic diagnosis • Standard parameters of diagnosis • Pattern recognition • Resemblance to normal histology • Cost and availability • Adult vs. pediatric tumors
Principles and limitations of histologic diagnosis • Standard parameters of diagnosis
Parameters used in diagnosis of pediatric tumors • Clinical features • Primary sites • Metastatic patterns • Radiographic features
Parameters used in diagnosis of pediatric tumors • Gross appearance • Microscopic appearance • histologic pattern • tumor cell cytology • Immunohistochemistry • Electron microscopy • Cytogenetics/molecular pathology
Principles and limitations of histologic diagnosis • Standard parameters of diagnosis • Pattern recognition
Pediatric Pathology Review Groups • Children’s Oncology Group • Pediatric Oncology Group • Children’s Cancer Group • Intergroup Rhabdomyosarcoma Study Group • National Wilms Tumor Study Group • SIOP • CWS
Principles and limitations of histologic diagnosis • Standard parameters of diagnosis • Pattern recognition • Resemblance to normal histology
Cellula est cellulas omnia (i.e. tumor cells come from normal cells). Rudolph Virchow
Principles and limitations of histologic diagnosis • Standard parameters of diagnosis • Pattern recognition • Resemblance to normal histology • Cost and availability
Test availability hierarchy • Routine histology • Immunostains • EM • Cytogenetics • Molecular testing • Gene arrays
Principles and limitations of histologic diagnosis • Standard parameters of diagnosis • Pattern recognition • Resemblance to normal histology • Cost and availability • Adult vs. pediatric tumors
Summary • Histologic diagnosis is part of a synthesis of clinical and pathological data. • Pattern recognition is the major technique used in histologic diagnosis and is a talent akin to bird-watching. • Diagnosis of tumors is based in part on their resemblance to normal cells.
Summary, cont. • Histologic examination is currently the most cost effective, readily available, and time efficient method of diagnosis. • Tumor diagnosis in children differs markedly from that of adults, but in some circumstances (e.g. sarcomas) it is the same.