What causes Primary gastrointestinal melanoma ?
What causes primary melanoma of the small intestine? The cause of primary melanoma of the small intestine is currently unknown. Theories include that the cancer originated from a undetectable primary tumor that spontaneously (naturally) regressed on its own; that the cancer originated from a primary tumor that is so small it can not be detected using standard clinical and laboratory investigations; lastly, because melanocytes are not normally found in the stomach, a final theory is that the melanocytes are in the stomach because early melanocyte cells lost their way during the development of the baby in the womb, and that these misplaced cells later became cancerous.