Malignant Infiltration of Bone Marrow
Many cancers may infiltrate the bone marrow, most common are carcinoma of the lung, breast, prostate, colon, and thyroid.
In malignant infiltration of bone marrow, the blood count may be normal although pancytopenia may occur and there may be leukoerythroblastic blood picture.
Marrow aspirates may be difficult because of fibrosis and trephine biopsies should also be performed.
The features of cancer cells include:
- A tendency to form clumps.
- High nuclear to cytoplasmic ratio.
- Nuclear moulding.
- Large prominent nucleoli.
Some tumors can be clearly identified by cytochemistry. Adenocarcinoma cells, for instance, may stain with mucin stains.
Other tumors can be very difficult to differentiate from hematological malignancies and cell marker studies may then be useful. The CD45 antigen is expressed on most hematological tumors but not other cancers.
The presence of lytic and blastic lesions on skeletal radiographic films is common in patients with prostate, lung, or breast cancer metastases.
Bone scans are sensitive for detecting bone metastases, while magnetic resonance imaging (MRI) scans of the involved area can detect marrow infiltration.
Treat the underlying disease and provide supportive measures for symptomatic patients.
In malignant infiltration of bone marrow, mortality is dependent on the underlying condition. The leukoerythroblastic blood picture is often associated with imminent death in some extreme cases. Patients with varying degrees of cytopenia are at risk for infection or bleeding.
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