Mature cystic teratomas can result in significant morbidity. Potential complications vary depending on the site of occurrence.

Sacrococcygeal teratoma

Sacrococcygeal teratomas are commonly diagnosed prenatally, and complications may occur in utero or during or after birth. The outcome after prenatal diagnosis is significantly worse than that in older postnatal surgical series, with survival rates ranging from 54-77%. [2, 22, 23]

Potential complications in utero include polyhydramnios and tumor hemorrhage, which can lead to anemia and nonimmune hydrops fetalis. If significant arteriovenous shunting occurs within the tumor, hydrops may result from high-output cardiac failure. Development of hydrops is an ominous sign. If it develops after 30 weeks' gestation, the mortality rate is 25%. If it is recognized, delivery is recommended as soon as lung maturity is documented. Development of hydrops before 30 weeks' gestation has an abysmal prognosis, with a 93% mortality rate. [22, 24] Makin et al reported that antenatal intervention for the treatment of fetal hydrops did not improve outcomes with neonatal deaths in 6 of 7 cases (86%). [2] Hydrops and prematurity are the two main factors that contribute to mortality.

Postpartum morbidity associated with sacrococcygeal teratomas is attributable to associated congenital anomalies, mass effects of the tumor, recurrence, and intraoperative and postoperative complications. Ten to twenty-four percent of sacrococcygeal teratomas are associated with other congenital anomalies, primarily defects of the hindgut and cloacal region, which exceeds the baseline rate of 2.5% expected in the general population. [25, 18, 5]

In one larger series that included 57 cases of benign teratomas over a 40-year period from a single institution, 5 recurrences were documented. Only one of the patients who experienced recurrence did not undergo a coccygectomy, and one patient who was thought to have a benign tumor with immature elements was found to have embryonal carcinoma after the third excision. In this same series, 3 patients had postoperative wound infections and one patient had postoperative pneumonia. The overall survival was 95% and morbidity or mortality rates were consistent over the 40-year period of the study. [9]

In a more recent series, all 26 patients diagnosed with benign teratomas survived. Seven of 20 patients with long-term follow-up developed neuropathic bladder or bowel disturbances. [18]

Partridge and colleagues studied a series of 45 patients, noting anorectal complications in 29% and urologic complications in 33%. These were associated with both prenatal obstructive findings and therapeutic interventions, as well as Altman classification, perineal reconstruction, and tumor recurrence. [26] A longitudinal cross-sectional follow-up study found that sequelae developing in childhood tended to improve with time, while functional symptoms reported in adulthood were common in the general population and not significantly increased over a control group. [27]

In a Dutch study of 47 adults who had been treated for SCT during infancy between 1970 to 1993, urinary incontinence was present in 30% and had a greater reported negative impact than unintentional defecation. Ten patients (21%) reported constipation; a tumor diameter of >10 cm and Altman type I or type II SCT were associated with constipation during adulthood. [28]

Ovarian teratoma

Complications of ovarian teratomas include the following:

Torsion

Rupture

Infection

Hemolytic anemia

Malignant degeneration.

Torsion is by far the most significant cause of morbidity, occurring in –3-11% of cases. Several series have demonstrated that increasing tumor size correlates with increased risk of torsion. [4, 29]

Rupture of a cystic teratoma is rare and may be spontaneous or associated with torsion. Most series report a rate of less than 1%, [4, 3] though Ahan et al reported a rate of 2.5% in their report of 501 patients. [19] Rupture may occur suddenly, leading to shock or hemorrhage with acute chemical peritonitis. Chronic leakage also may occur, with resultant granulomatous peritonitis. Prognosis after rupture is usually favorable, but the rupture often results in formation of dense adhesions.

Infection is uncommon and occurs in less than 1-2% of cases. Coliform bacteria are the organisms most commonly implicated. [19, 29]

Encephalitis associated with antibodies against the N-methyl D-aspartate receptor (NMDAR) has been linked to tumors, especially ovarian mature teratomas. In a series of 400 cases, 335 of them in women, 165 patients (49%) had tumors and all but six were ovarian teratomas. The syndrome is characterized by a viral-like prodrome followed by a multistage progression of symptoms that includes psychosis, memory deficits, seizures, language disintegration, decreased consciousness, dyskinesias, and autonomic instability. Substantial recovery is usually seen with tumor resection and immunotherapy. [30]

Autoimmune hemolytic anemia has been associated with mature cystic teratomas in rare cases. In these reports, removal of the tumor resulted in complete resolution of symptoms. Theories behind the pathogenetic mechanism include (1) tumor substances that are antigenically different from the host and produce an antibody response within the host that cross reacts with native red blood cells, (2) antibody production by the tumor directed against host red blood cells, and (3) coating of the red blood cells by tumor substance that changes red blood cell antigenicity. In this context, radiologic imaging of the pelvis may be indicated in cases of refractory hemolytic anemia. [31, 32]

In its pure form, mature cystic teratoma of the ovary is always benign, but in approximately 0.2-2% of cases, it may undergo malignant transformation into one of its elements, the majority of which are squamous cell carcinomas. The prognosis for patients with malignant degeneration is generally poor but dependent on stage and degenerated cell type. [4, 33]

Testicular teratoma

Testicular teratomas occur in children and adults, but their incidence and natural history contrast sharply. Pure teratomas comprise 38% of germ cell tumors in infants and children but only 3% after puberty. In children, they behave as a benign tumor, whereas in adults and adolescents they are known to metastasize. [20, 34] With no documented cases of metastasis, morbidity from prepubertal testicular teratomas is largely limited to surgical or postoperative complications.

During and after puberty, all teratomas are regarded as malignant because even mature teratomas (composed of entirely mature histologic elements) can metastasize to retroperitoneal lymph nodes or to other systems. Reported rates of metastasis vary from 29-76%. Morbidity is associated with growth of the tumor, which may invade or obstruct local structures and become unresectable. Approximately 20% of patients relapse during surveillance. [20]

Mediastinal teratoma

Mature teratomas of the mediastinum, the most common mediastinal germ cell tumor, are benign lesions. They do not have the metastatic potential observed in testicular teratoma and are cured by surgical resection alone. Because of their anatomic location, intraoperative and postoperative complications are the only significant source of morbidity, as other intrathoracic structures are often intimately involved with the tumor. [35]