A) Gynecologic Masses

Ovaries
Benign
Functional (physiologic) cyst [Corpus luteum cyst, Follicular cyst]
Luteoma of pregnancy
Theca lutein cyst
Polycystic ovaries (PCOS)
Endometrioma
Cystadenoma
Benign ovarian germ cell tumor (eg, mature teratoma)
Benign sex cord-stromal tumor
Ovarian torsion
Malignant or borderline
Ovarian Cancer
-Epithelial carcinoma
-Malignant ovarian germ cell tumor
-Malignant sex cord-stromal tumor
Epithelial borderline neoplasm
Fallopian tubes
Benign
Ectopic pregnancy
Hydrosalpinx
Malignant or borderline
Epithelial carcinoma
Serous tubal intraepithelial neoplasia
Outside the Ovaries and Fallopian tubes
Benign
Paraovarian cyst
Paratubal cyst
Uterine leiomyoma (pedunculated or cervical)
Tubo-ovarian abscess or Pelvic inflammatory disease (PID)
Malignant or borderline
Metastatic endometrial carcinoma

B) Non-Gynecologic Masses

Benign
Constipation
Appendiceal abscess
Diverticular abscess
Peritoneal cyst
Nerve sheath tumor
Pelvic abscess
Bladder diverticulum
Ureteral diverticulum
Pelvic kidney
Malignant or borderline
Appendiceal neoplasm
Bowel neoplasm
Metastasis (eg, breast, colon, lymphoma)
Retroperitoneal sarcoma

Understanding the Differential Diagnosis
Adrenal masses can be divided into two broad anatomic categories: Gynecologic vs. Non-gynecologic.
-Gynecologic masses are found in 1) the ovaries, 2) fallopian tubes, 3) Uterus, or 4) associated with the first three (e.g. tubo-ovarian abscess, para-ovarian cyst, para-tubal cyst, pedunculated uterine leiomyoma)
-Non-gynecologic masses are found in places like the appendix, colon, bladder, ureters, etc.
-Masses in each of these anatomic locations can be 1) benign or 2) malignant or borderline.

Corpus luteal cysts are a type of functional ovarian cyst that results when a corpus luteum fails to regress following the release of an ovum. There are two types of functional cysts: 1) Corpus luteum cyst and 2) Follicular cyst.

References / Further Reading
Clin Obstet Gynecol 2015; 58:53. Adnexal mass in the postmenopausal patient. https://www.ncbi.nlm.nih.gov/pubmed/25565080

Hochberg, MD & Hoffman, MD. Differential diagnosis of the adnexal mass. Post TW, ed. UpToDate. Waltham, MA: UpToDate Inc. http://www.uptodate.com(Accessed on March  10, 2018.)

Am Fam  Physician 2016;93(8):676-681. Diagnosis and management of adnexal masses. https://www.aafp.org/afp/2016/0415/p676.html

https://radiopaedia.org/articles/corpus-luteal-cyst

print