A postoperative spindle cell nodule is a noncancerous, or benign, growth that forms in tissue that is healing after a surgery or procedure. It is made of long, thin cells called spindle cells, which are part of the body’s normal repair process. Most postoperative spindle cell nodules are found in the bladder, the prostate, or the vagina.
Under the microscope, a postoperative spindle cell nodule can look worrying, because the cells are growing quickly and many are dividing. For this reason, the growth can resemble a type of cancer called a sarcoma. However, it is a healing reaction rather than a cancer, and it does not spread to other parts of the body.
This article explains why a postoperative spindle cell nodule forms, how the pathologist tells it apart from cancer, and what your pathology report means for your care.
A postoperative spindle cell nodule forms as part of the healing process after tissue has been cut, scraped, or burned during a procedure. When tissue is injured, cells called myofibroblasts move into the area and multiply to repair it. In a postoperative spindle cell nodule, this repair process is more active than usual and forms a small lump.
The procedures most often linked to a postoperative spindle cell nodule include:
A postoperative spindle cell nodule usually appears within a few weeks to about three months after the procedure.
Many postoperative spindle cell nodules cause no symptoms and are found during a follow-up examination after surgery. In the bladder, the nodule can cause blood in the urine, which is usually noticed in the weeks after the procedure. A larger nodule can make it harder to start urinating or to empty the bladder completely. In the vagina, it may cause bleeding or be felt as a small lump.
The diagnosis of a postoperative spindle cell nodule is made by a pathologist after the growth is removed or sampled with a biopsy. In the bladder, the nodule is usually found during follow-up cystoscopy and removed in the same way as a bladder tumor. Because it can look like a cancer to the urologist or surgeon, examination under the microscope is needed to make the diagnosis.
Under the microscope, the pathologist sees the following features:
The most important clue for the pathologist is the history of a recent procedure at the same site. Your surgeon or urologist usually includes this information when sending the tissue, and the pathologist may mention it in the report. Some tests on the tissue, described in the next section, help confirm the diagnosis.
Immunohistochemistry is a test that uses special stains to show which proteins are made by the cells in a postoperative spindle cell nodule. The results help the pathologist confirm that the cells are healing myofibroblasts and rule out cancers that can look similar. The stains used, and how the results are worded, vary between laboratories. Results you may see in your report include:
Not every postoperative spindle cell nodule needs every stain. In a typical case with a clear history of a recent procedure, only a few stains may be needed.
A postoperative spindle cell nodule belongs to a group of growths made of myofibroblasts, sometimes called myofibroblastic proliferations. The pathologist uses the history, the appearance of the cells, and the stain results to decide which diagnosis fits best. Your report may name one of these related diagnoses instead:
When a postoperative spindle cell nodule is removed, the pathologist may comment on whether the growth reaches the edges of the tissue sample, called the margins. For a bladder nodule removed through the urethra, the tissue comes out in small pieces, so margins usually cannot be assessed. Because the nodule is not a cancer, a growth that reaches the margin does not usually need more surgery.
A postoperative spindle cell nodule usually does not come back after it is removed. It does not turn into cancer, and it does not spread to lymph nodes or other parts of the body. If a similar growth appears again, it is usually examined again to confirm the diagnosis.
After a diagnosis of a postoperative spindle cell nodule, treatment is usually simple, because the growth is benign. Chemotherapy and radiation are not needed for this healing reaction. Your doctor will decide on next steps based on where the nodule is, its size, and whether it is causing symptoms.