Hello from JustAnswer.
If these other lumps appear similar to the lump that was removed, then yes, they would typically be removed. They do not carry the same prognosis as cancer, and can generally be treated with conservative surgical removal (rather than a wider excision that would be necessary for cancer), but they are still generally removed.
However, we also usually see atypical fibroxanthomas on skin that has higher sun exposure, such as the head and neck. The extremities also can receive much sun exposure, but it is less common for the trunk to develop atypical fibroxanthomas.
So, the first step would be review of the other lumps to see if they also have the appearance of an atypical fibroxanthoma, and if they also look worrisome, it would be appropriate to then consider removal.
If I can provide any additional information, please let me know.
Please let me know if I can provide any further assistance.