<unk> s are part of the surface epithelial-stromal<unk>  group of ovarian<unk> s, which derive from Mullerian epithelium. They are common neoplasms with a strong tendency to occur bilaterally, and they account for approximately a quarter of all ovarian<unk> s.
Serous tumour
Stoma 
Seroma
Embryoma
Noma 
Mixed tumor
Ovarian cyst
Pseudocyst