Is incidentaloma a form of cancer?  

Incidentaloma is NOT a form of cancer.

According to the Exploring Medical Language textbook:

Incidentaloma refers to a mass lesion involving an organ that is discovered unexpectedly [incidentaly] by the use of ultrasound, computed tomography scan [CT], or magnetic resonance imaging [MRI] and has nothing to do with the patient’s symptoms or primary diagnosis.

Incidentaloma ends with the suffix –oma, meaning tumor, which is often seen in medical terms for cancer, such as in melanoma, a form of skin cancer.

Incidental findings of incidentalomas may lead to unnecessary testing and treatment,  known as the “cascade effect.”