Conservative management of a pelvic Schwannoma presenting as an adnexal mass

Primary retroperitoneal tumor during pregnancy: Case report and review of the literature

OBJECTIVE

To report the case of a pregnant patient diagnosed with a primary retroperitoneal tumor and to conduct a review of the literature pertaining to the diagnosis, treatment and maternal-fetal prognosis of this disease condition during pregnancy.

METHODS

A 19-year-old patient who presented with a retroperitoneal tumor identified on ultrasound. The results of the percutaneous biopsy showed a benign tumor. A healthy neonate was delivered by cesarean section. Surgical resection was performed four months later, and histopathology showed a mature cystic teratoma. A search was conduced in the Medline via PubMed, Lilacs, SciELO and ScienceDirect databases using the terms "pregnancy," "neoplasms," and "retroperitoneal neoplasms," including case reports and case series of retroperitoneal tumors during pregnancy. Diagnosis, treatment and maternal-fetal prognosis were identified.

RESULTS

Overall, 1658 titles were identified. Of these, 34 case reports and 1 case series met the inclusion criteria. Of the cases, 62.9 % were benign. Diagnosis was made as an incidental finding in 63 % of cases, and 77 % of the masses were identified on ultrasound. Percutaneous biopsy was used in 8 % of cases, including the case reported here. Surgical treatment was used in 88 % of cases usually after delivery. Maternal mortality occurred in 8.5 % of cases. Fetal prognosis was good in 65 % of the pregnancies.

CONCLUSIONS

Despite being frequently benign, retroperitoneal tumors during gestation have a reserved maternal and fetal prognosis in a substantial number of cases. There is a need to assess the risks and benefits of percutaneous biopsy.

The natural history of incidental retroperitoneal schwannomas

The natural history of asymptomatic retroperitoneal schwannomas is poorly understood. This study aimed at investigating the natural history of incidental retroperitoneal schwannomas. The medical charts and imaging studies of 22 asymptomatic patients under observation for at least 12 months for retroperitoneal schwannomas were reviewed. The duration of follow-up ranged between 13 and 176 months (mean 48 months). In the 22 patients managed by the “wait and see” approach, the average tumor size at initial presentation was 51 mm, which increased to 57 mm at final follow-up. During the final follow-up, 2 patients required surgical treatment for tumor enlargement, while the remaining patients remained asymptomatic without surgery. The average growth rate of the tumors was 1.9 mm/year (range: -1.9 to 8.7 mm/year). The majority of asymptomatic retroperitoneal schwannomas demonstrate minimal growth and may be suitable for management with the “wait and see” approach.

Pelvic schwannoma in the right parametrium

Neurilemomas are benign usually encapsulated nerve sheath tumors derived from the Schwann cells. These tumors commonly arise from the cranial nerves as acoustic neurinomas but they are extremely rare in the pelvis and the retroperitoneal area (less than 0.5% of reported cases), unless they are combined with von Recklinghausen disease (type 1 neurofibromatosis). We report the case of a 58-year-old female with pelvic schwannoma, 6.5 × 5.5 cm in size, in the right parametrium. This is the first case reported in the literature. Based on the rarity of this tumor and in order to ensure optimum treatment and survival for our patient, we performed laparotomy with total abdominal hysterectomy and en-block tumor excision. A frozen section was taken during the surgery before complete resection of the mass, which was ambiguous. Because of the possibility of malignancy, complete excision of the mass was performed, with pelvic blunt dissection. Histological examination showed a benign neoplasm, originating from the cells of peripheral nerve sheaths; diagnosis was a schwannoma. There were degenerative areas, including cystic degeneration, hemorrhagic infiltrations, ischemic foci with pycnotic cells, and collagen replacement. Pelvic schwannomas are rare neoplasms that can be misdiagnosed. Laparoscopy is a safe and efficient option for approaching benign pelvic tumors and might offer the advantage of better visualization of structures due to the magnification in laparoscopic view, especially in narrow anatomic spaces.