• A high power view of a metastatic adenocarcinoma
• The orange pointer points to a spicule of normal bone
in this tissue.
• The two green arrows flank an acinus-like structure in
this metastatic tumor.
• However, unlike normal acinar structures, notice that
the nuclei are not ordered neatly around the basement
membrane of this acinous, but extend close to the
luminal surface of the gland.
• Note as well, the disordered arrangement of the nuclei
elsewhere and a tendency to be elongated, rather than
spherical as in a normal gland.
• This tumor probably arose in the colon.
|Metastatic Tumor in Bone|
arise as part of the natural history of
malignancies in various organs.
•Spread may occur through direct
extension (from viscera in
close proximity to bones); by vascular or lymphatic
dissemination; or by direct seeding.
•The resorption of bone seen in the vicinity of tumor metastases
is believed to be due to activation of osteoclasts by
cytokines aberrantly secreted by tumor cells.
•Similarly, excess mineralization seen in some cases of tumor
deposits in bone is also due to inappropriate cytokine release
from the tumor cells.
•Malignancies of various organs and tissues commonly
metastasize to bone.
•Malignancies of breast, prostate, lung, kidney and thyroid are frequent sources of metastatic deposits in bone.
•Metastases in bone
manifest themselves by a
pathological fracture or severe intractable bone pain.
•Pathological fractures are fractures of bones which occur
as a result of stress normally insufficient to break a bone.
|General Gross Description|
•Grossly, lesions replace bone and appear as soft
masses of varying sizes.
•Hemorrhage and necrosis are frequently seen.
•Lesions can contain gritty areas due to reparative bone
deposition within the tumor.
|General Micro Description|
•The tumor deposits resemble the primary tumor.
•In some instances, the metastasis may be more or less
well differentiated than the primary focus.
•There is often evidence of osteoclastic activity and bone
resorption in the vicinity of the tumor. Some tumors (such
as adenocarcinoma of the prostate) may cause bone
deposition due to activation of osteoblasts.
• Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th edition. Philadelphia, W.B. Saunders, 1994, pp. 1246.