Patholgy Slides : Tumors or Neoplasia
Malignant tumors of the connective tissue
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Malignant tumors of the connective tissue (sarcomas, from Greek sarkoma - "fleshy", because the gross aspect these tumors) are much more rare, comparing with carcinomas. Ninety percent of them are diagnosed in children and young adults, being localized mainly in lower extremities (40 %), retroperitoneum (30 %), upper extremities (20 %), head and neck (10 %).
Nomenclature : type of the tissue to which the malignant tumor will differentiate + "sarcoma".
Fibrosarcoma (fibroblastic sarcoma) is a malignant connective (soft) tissue tumor which originates from fibroblasts. The tumor may present different degrees of differentiation : low grade (differentiated), intermediate malignancy and high malignancy (anaplastic). The degree of differentiation is set according with: resemblance of tumor cell with mature fibroblast (spindle-shaped), amount of collagen secretion and mitotic rate. Tumor cells are arranged in short fascicles which split and merge, giving the appearance of "fish bone". Poorly differentiated tumors consist in more atypical cells, pleomorphic, giant cells, multinucleated, numerous atypical mitoses and reduced collagen production. Presence of immature blood vessels (sarcomatous vessels lacking endothelial cells) favors the bloodstream metastasizing. (Hematoxylin-eosin, ob. X20)
Osteosarcoma (osteogenic sarcoma)
Osteosarcoma (osteogenic sarcoma) (H&E, ob. x10)
Osteosarcoma (osteogenic sarcoma) is a malignant tumor whose neoplastic cells present osteoblastic differentiation and form tumor bone. Tumor cells are very pleomorphic (anaplastic), some are giant and present numerous and atypical mitotic figures. These cells produce osteoid describing irregular trabeculae (amorphous, eosinophilic/pink) with or without central calcification (hematoxylinophilic/blue, granular) - tumor bone. Tumor cells are included in the osteoid matrix. Cartilage may be present. Presence of immature blood vessels (sarcomatous vessels lacking endothelial cells) favors the bloodstream metastasizing. (Hematoxylin-eosin, ob. x10)