spindle cell sarcoma
Meaning of spindle cell sarcoma: A description of shape rather than a single disease, since many unrelated cancers look this way and shape alone cannot separate them.
Definition of spindle cell sarcoma
Spindle cell sarcoma is a cancer of connective tissue whose cells are long and tapered at both ends, like a weaving spindle, and which usually grow in interlacing bundles. The name describes what the tumor looks like under the microscope rather than which tissue it came from, so it covers several distinct diseases with different behavior and different treatment.
Which tumors look like this?
Many, and they are not close relatives.
| Tumor | Cell it arises from |
|---|---|
| Fibrosarcoma | Fibrous tissue cells |
| Leiomyosarcoma | Smooth muscle |
| Malignant peripheral nerve sheath tumor | Cells wrapping a nerve |
| Synovial sarcoma | Uncertain, defined by a gene fusion |
Each has its own tendency to return locally or to spread, and in some cases its own targeted treatment, so stopping at the shape leaves the most useful information unrecovered.
Why is the shape not a diagnosis?
Because cancers that are not sarcomas can look identical. A carcinoma, which arises from a lining or a gland, sometimes abandons its usual sheet-like arrangement and grows as spindled cells, producing a spindle cell cancer that imitates a sarcoma closely. Melanoma does the same. Telling them apart relies on stains that detect proteins particular to each family, and increasingly on tests for the gene rearrangements that define certain sarcomas. The distinction is not academic, since a tumor arising from a lining is treated along entirely different lines from a true sarcoma.
What decides the outlook?
Grade and site do most of the work, not the descriptive label. Pathologists score how closely the tumor still resembles normal tissue, how many of its cells are dividing, and how much of it has died from outgrowing its blood supply. That score predicts behavior better than the name does. Size and depth count too, and a tumor sitting deep in a limb or in the abdomen is both larger before it is noticed and harder to remove whole. Where no specific line of origin can be established after full testing, it is reported as a spindle cell soft tissue sarcoma not otherwise specified, which records the limit of what could be determined.
Also known as
Used in a sentence
The biopsy showed a high grade spindle cell sarcoma of the thigh.
Good to know
Spindle cell appearance is shared by sarcomas, by carcinomas that have taken on a spindled pattern, and by melanoma, so the description alone does not establish the family of tumor and immunohistochemical or molecular testing is required.
Word origin
Where “spindle cell sarcoma” comes from
Sarcoma comes from the Greek sarx, meaning flesh, with the ending -oma, meaning tumor.