Benign Ovarian Cyst (e.g., Dermoid or Serous Cystadenoma): This is the most common cause of a septated cyst in the ovary. These cysts are often filled with fluid and can have septations, which are internal divisions within the cyst. They are usually benign and can be monitored or surgically removed if necessary.

Ovarian Endometrioma: This condition occurs when endometrial tissue grows within the ovary, forming a cyst. Endometriomas can appear septated on imaging and are often associated with endometriosis.
Mucinous Cystadenoma: A type of benign ovarian tumor that can have septations and is filled with mucin, a thick, jelly-like substance.
Serous Cystadenocarcinoma: Although less common than benign causes, this malignant tumor can also present as a septated cyst in the ovary.

Ovarian Torsion: While not directly a diagnosis of the cyst itself, ovarian torsion is a serious condition that can occur in the presence of any ovarian mass, including septated cysts. It requires immediate medical attention to prevent tissue death.
Borderline Ovarian Tumor: These are tumors that have a low potential for malignancy but can still cause significant problems. They may appear as septated cysts and require careful evaluation.
Germ Cell Tumor: Although rare, germ cell tumors (like dysgerminomas) can present as septated masses in the ovary and have the potential for malignancy.

Krukenberg Tumor: A rare metastatic tumor to the ovary, typically from a primary site in the gastrointestinal tract, which can appear as a septated cyst.
Ovarian Lymphoma: Primary ovarian lymphoma is extremely rare and can present with various imaging findings, including septated cysts.
Schiller-Duval Bodies in Yolk Sac Tumor: A very rare germ cell tumor that can have a characteristic appearance on imaging, including septations.