Yes, DICTYOSOME is a Scrabble word!

Letter values in Scrabble US: D 2, I 1, C 3, T 1, Y 4, O 1, S 1, O 1, M 3, E 1.

Is it a valid word?

DICTYOSOME is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a netlike structure in the cytoplasm of animal cells (especially in those cells that produce secretions)

Also: golgi body, golgi apparatus, golgi complex.