Floret-like cells are large cells with several nuclei arranged in a ring around the edge of the cell. The ring of nuclei looks like the petals of a small flower, or floret, which is how the cells got their name. They are a type of multinucleated giant cell.
Floret-like cells describe what the pathologist saw under the microscope, not a diagnosis on their own. They are best known as a feature of a noncancerous fatty tumor called pleomorphic lipoma. This article explains what floret-like cells look like, where they are found, and what they mean in your pathology report.
What do floret-like cells look like under the microscope?
Floret-like cells are much larger than the cells around them. Each one contains several dark nuclei that sit side by side near the edge of the cell, often forming a partial or complete ring. The center of the cell is filled with pink material.
The nuclei in floret-like cells may look large and dark. This can appear worrying, but in the right setting it is a known feature of a noncancerous tumor. The pathologist considers the overall appearance of the tumor rather than these cells alone.
Floret-like cells can resemble Touton giant cells, which also have a ring of nuclei. Touton giant cells, however, have a pale, foamy outer rim and are made by immune cells.
Where are floret-like cells found?
Floret-like cells are most often seen in the following tumors:
- Pleomorphic lipoma. A pleomorphic lipoma is a noncancerous fat tumor, usually found in the back of the neck, upper back, or shoulders. Floret-like cells are a characteristic feature.
- Spindle cell lipoma. A spindle cell lipoma is closely related to pleomorphic lipoma. Many tumors show features of both, and floret-like cells may be present.
Floret-like cells are occasionally seen in other tumors, including some cancerous fatty tumors. For this reason, their presence alone is not enough to make a diagnosis.
How are floret-like cells identified?
A pathologist identifies floret-like cells while examining the tissue on routine slides. No special test is needed to see them.
When floret-like cells are found in a fatty tumor, the pathologist often uses additional tests to confirm the diagnosis. These may include:
- CD34. The cells of a pleomorphic lipoma and spindle cell lipoma are usually positive for CD34.
- RB1. These tumors usually show loss of the RB1 protein on immunohistochemistry.
- MDM2. Testing for MDM2 helps rule out an atypical lipomatous tumor, a fatty tumor that can look similar under the microscope. Pleomorphic lipoma does not show extra copies of the MDM2 gene.
What do floret-like cells mean for me?
The meaning of floret-like cells depends on the final diagnosis. In a pleomorphic lipoma or spindle cell lipoma, they are an expected finding and do not mean cancer. These tumors rarely come back after removal. Your report will list the final diagnosis separately.
Questions to ask your doctor
- What is the final diagnosis in my report?
- Is the tumor noncancerous or cancerous?
- Were additional tests such as CD34, RB1, or MDM2 done?
- Was an atypical lipomatous tumor ruled out?
- Was the tumor completely removed?
- Do I need any further treatment or follow-up?
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