I had a ct scan identifying 6.5 x 6.6 x 8 cm intra-abdominal fatty mass indenting my right colon. there is no pain. i have a past history of melanoma and some adenopath. what should i do?

Colon tumor: Location worrisome differential diagnosis extensive inluding multiple cancers could be lipoma biopsy and removal indicated.

Biopsy essential: It is impossible to move forward without a biopsy of this (presumably new) mass. Anything else is needless speculation.

Sarcoma: This sounds more like a liposarcoma. Time to schedule an appointment with your friend surgeon.