Fig.: a rhetorical question asked by a person who feels underappreciated by others or even ignored on a social level.
(colloquialism)

We are all together here because this is a family issue, but you don't even care what I have to say about it. What am I, chopped liver?

Siamo tutti qui assieme perché questo è un problema di famiglia, ma a voi non interessa nemmeno quello che ho da dire al riguardo. Chi sono io, il figlio della serva?

The new boss talked to all the employees in the office, but he didn't talk to me! What am I, chopped liver?

Il nuovo direttore ha scambiato due parole con tutti gli impiegati in ufficio, tranne che con me. Chi sono io, il figlio della serva?

As the divorcing couple divided up their assets, completely ignoring the future of their child, the kid thought to himself "What am I, chopped liver?"

Quando la coppia in procinto di divorziare si mise a discutere su come dividere le loro proprietà senza minimamente preoccuparsi del futuro del figlio, il bambino pensò tra sé e sé "Chi sono io, il figlio della serva?"

The origin of this expression is not clear. One theory is that chopped liver - which is not really appreciated by everyone - was traditionally served as a side dish and it would be normally overlooked by the main course.
In 1971, Dick Cavalli created the comic strip "Winthrop" where the expression appears in its modern format