Dysplasia — recognizable morphologic changes in cells that indicate the presence of genetic mutations beginning the development of a neoplasm. Usually grading dysplastic changes based on the thickness of the involved epithelium: less than 1/3 mild atypical proliferation. less than 2/3 moderate atypical proliferation. more than 2/3 severe atypical proliferation.
eg: Dysplastic change of cervical epithelium infected by HPV
Anaplasia — recognizable morphologic changes in the tumor cells lack of differentiation; literally means “to form backward”, implying a ‘reverse differentiation’ of mature normal cells. It is considered a hallmark of malignant transformation.
eg: Anaplastic Rhabdomyosarcoma
Dysplasia Dysplastic change in cervical epithelium
Tumors of lymphocytes are always malignant – called lymphoma
Tumors of melanocytes
Benign – nevus
Malignant - melanoma
Benign vs Malignant Tumor Characteristics Benign Malignant Morphology and Differentiation Well-differentiated appearance Structure similar to tissue origin Little or no anaplasia Usually some lack of differentiation Structure often atypical Variable degree of anaplasia Rate and pattern of growth Slow, progressive expansion Rare mitotic figures Normal-appearing mitotic figures Slow to rapid growth; erratic growth rate Mitotic figures often numerous Mitotic figures sometimes abnormal Local invasion No Invasion Cohesive and expansile growth Capsule often present Local Invasion Infiltrative growth Usually no capsule Metastasis No metastasis Frequent metastasis (definitive criteria for malignancy) Damage to human body Relatively smaller Relatively bigger Prognosis Good Bad
Staging of Malignant Neoplasms Stage Definition Tis In situ, non-invasive (confined to epithelium) T1 Small, minimally invasive within primary organ site T2 Larger, more invasive within the primary organ site T3 Larger and/or invasive beyond margins of primary organ site T4 Very large and/or very invasive, spread to adjacent organs N0 No lymph node involvement N1 Regional lymph node involvement N2 Extensive regional lymph node involvement N3 More distant lymph node involvement M0 No distant metastases M1 Distant metastases present
Microscopic morphology : consisted of a cystic structure lined with keratinized stratified squamous epithelium and solid nests of parenchymal squamous cells, no mitotic figures, a dense lymphoid element with follicles in the stroma.
Immunohistochemistry : CK (+), CK5/6(+), p63(+), p53(+)
Pathological diagnosis ： keratocystoma of parotid gland.
XXX, M/37y,Pathological No: xxxxxx, the left parotid gland mass
Learning without thinking leads to confusion, thinking without learning ends in danger. 学而不思则罔 , 思而不学则殆 -Kong Zi Learning is like rowing upstream: not to advance is to drop back 学如逆水行舟 , 不进则退