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A pathologist is examining a microscopic section taken
from a tumor. The section shows poorly formed
osteoid,containing pleomorphic tumor cells with large
hyperchromatic nuclei. Abnormal mitotic figures are
also seen. Immunohistochemical staining shows that
the tumor cells are strongly positive for alkaline phos-
phatase. Which of the following would most likely be
the site oforigin ofthis tumor?
(A) Femur ofa 21-year-old man
(B) Pelvis ofa 45-year-old woman
© Skull ofa 40-year-old woman
(D) Tibia ofa 5-year-old girl
(E) Vertebrae ofa 17-year-old boy
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hi
i'm thinkig may b paget's or osteogenic sarcoma.. pagets in elderly male.. but not able to pick from choice.. n if it's osteogenic sarcoma.. may b the femur or tibia...eerrr...
good question.. need to think about this..
B or C..
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A)osteogenic sarcoma.. commonest site femur
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you got it aimhigh.correct ans is a.
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aimhigh u r all set for yr exam. Best of luck
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to aimhigh...
how was your reasoning to come up with the answer pleasE?
i still do not get it with the facts given........what exactly directed you to the answer
thanks
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Osteosarcoma
Pathology
The tumor may be localized at the end of the long bones. Most often it affects the upper end of tibia or humerus, or lower end of femur. The tumor is solid, hard, irregular ("fir-tree" or "sun-burst" appearance on X-ray examination) due to the tumor spicules of calcified bone radiating in right angles. These right angles form what is known as Codman's triangle. Surrounding tissues are infiltrated.
Microscopically: The characteric feature of osteosarcoma is presence of osteoid (bone formation) within the tumour. Tumor cells are very pleomorphic (anaplastic), some are giant, numerous atypical mitoses. 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. Depending on the features of the tumour cells present (whether they resemble bone cells, cartilage cells or fibroblast cells), the tumour can be subclassified.
