Parovarian Cyst

PAROVARIAN CYST, a tumor developing from the parovarium (paroophoron) and situated between the leaves of the broad ligament (intraligamentary cyst). Parovarian cysts constitute on average 8-10% of all ovarian tumors and occur in the age range of 20 to 30 years. Under the microscope, cross-sections of parovarian cords appear as tubes lined inside with a single-layered ciliated cylindrical epithelium. On the outside, these tubes are surrounded by a capsule consisting of muscular and connective tissue cells. It is also noted that the lumen of the tubes in places forms more or less significant expansions, while in other areas the tubes appear obliterated. Individual cells of the cylindrical epithelium, under the influence of unknown causes, transform into small cysts. Parovarian cysts arise as a result of the retention and accumulation of secretions in the lumen of the parovarian tubes. Intrauterine atresies thus cause the development of congenital parovarian cysts. Tumors that develop later are formed due to the blockage of the ducts with thickened secretions or compression by a scar on the basis of trauma and infection. The cyst grows slowly; the epithelium of its walls remains single-layered and does not proliferate. In large cysts, the epithelium flattens and sometimes desquamates; the muscular layer of the cyst wall undergoes atrophy, and connective tissue cells form a thin fibrous capsule. On the outside, the cyst is covered by the peritoneum of the pelvis. By mechanism of formation and formal genesis, parovarian cysts are not true blastomas, but should be classified as retention cysts. As a rule, they are unilocular, in rare cases the entire formation represents a group of fused unilocular cysts. The size of parovarian cysts varies widely depending on the amount of accumulated fluid and can reach the size of an adult human head. Giant cysts containing several tens of liters of fluid have been described. The contents of parovarian cysts—colorless, water-like liquid, slightly opalescent, with a specific gravity of 1.004-1.009, alkaline reaction, with a significant content of NaCl. When heated and acetic acid is added, a light precipitate forms; mucus and pseudomucin are not detected. The fluid is poor in formed elements, occasionally destroyed or preserved ciliated epithelial cells and a few ameboid bodies are found. Developing between the ligaments, parovarian cysts mainly bulge the posterior leaf of the broad ligament. They can gradually fill the entire pelvis and displace the uterus forward and upward; the tube and round ligament at the same time are spread out over the surface of the tumor. An immobile intraligamentary tumor results. In other cases, the tumor stretches the pliable peritoneal leaf so much that a broad pedicle forms, allowing the cyst to enter the greater pelvis, creating conditions for torsion of the pedicle. Small cysts do not cause any painful symptoms. As they grow, interligamentary tumors begin to compress the surrounding pelvic organs, resulting in disturbances in the function of the bladder and rectum. Compression of pelvic nerves and veins causes pain, anesthesia, cramps, paresis, edema, and varicose veins of the lower extremities. However, these phenomena are not always observed. Torsion of the cyst pedicle is rare and is accompanied by corresponding symptoms; rupture of the cyst with spillage of contents into the abdominal cavity does not cause signs of peritoneal irritation, the fluid is absorbed without any reaction. Tumors extending beyond the pelvis cause abdominal enlargement and are detectable by percussion and palpation. On bimanual examination, a smoothing or bulging of one of the lateral fornices is noted; the uterus is displaced to the side or upward, and the vaginal part of the cervix is correspondingly displaced to the side or located high behind the symphysis pubis. To the side of the uterus and closely adjacent to it is a limited mobility tumor of uniformly round or oval shape, elastic consistency, fluctuating. Next to the tumor, the ovary can be palpated, sometimes spread over the surface of the tumor and merging with it, as an area of denser consistency. On rough examination, the tumor can easily rupture under the fingers. Parovarian cysts must first be differentiated from ovarian cysts, which are more mobile and wander in the abdominal cavity; with them, the ovary cannot be palpated separately. In examining a patient with a very large ovarian cyst, emaciation, dilation of the veins of the anterior abdominal wall, and a characteristic facial expression ('facies ovariana') are noted. Then one should remember the possibility of hydrosalpinx and tubo-ovarian cysts of inflammatory origin. Finally, echinococcus should be kept in mind, usually located in the posterior Douglas pouch and recognizable by blood examination, serological and biological reactions. The prognosis in parovarian cysts is favorable. Treatment is only surgical; indications are mainly compression of pelvic organs and pain. Due to the exceptional rarity of malignant degeneration and the low danger of pedicle torsion, indications for surgery in parovarian cysts arise much less frequently than in ovarian cysts. Among the features of surgical technique, it should be noted the enucleation of the tumor by blunt dissection through an incision in the peritoneal leaf over the tumor, then the necessity of avoiding damage to the ureter and large vessels. If malignant degeneration is suspected (papillary growths), the tumor is removed together with the uterus. On cysts of the parovarium. Sib. med., 1926, No. 1. See also A. Aleksandrov.