Hemorrhagic, calcified, and ossified benign retroperitoneal schwannoma

Abstract

Background:Schwannomas are mesenchymal tumors arising from the neural sheaths of peripheral nerves. They can almost develop in any part of the body, while head, neck and extremities are the most common sites. Occurrence in the retroperitoneum is rare. Schwannomas can show secondary degenerative changes including cyst formation, hyalinization, hemorrhage, and calcification, whereas the ossified retroperitoneal schwannoma was only reported in a malignant one.Case summary:We first present a benign ossified retroperitoneal schwannoma in a 61-year-old female. The mass was found by a routine health examination. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a well-defined mass in the area among duodenum, right liver, and kidney. Definitive preoperative diagnosis of the mass was difficult. By laparotomy, the mass was found in the retroperitoneum. We completely removed the tumor and gross specimen showed a mass with a capsule and 6 × 6 × 4.8 cm in size. Microscopic examination showed the tumor is composed of spindle-shaped cells with degenerative changes of hemorrhage, calcification, and ossification. Immunohistochemically, S-100 protein was strongly positive. Finally, the mass was diagnosed as a hemorrhagic, calcified, and ossified benign schwannoma in the retroperitoneum. The patient was followed up for a period of 21 months, during which she was well with no evidence of recurrence.Conclusion:We report the first case of a benign retroperitoneal schwannoma with secondary degenerative changes including hemorrhage, calcification, and ossification. Precise preoperative diagnosis of the tumor is challenging even with multiple preoperative imaging modalities. After complete resection, patients with benign retroperitoneal schwanommas generally have good prognosis.

Calcification and ossification in conventional schwannoma: A clinicopathologic study of 32 cases

“…The majority of tumors with calcification in our cohort arose in association with the spinal nerve roots (10 cases), with the cervical and thoracic regions most commonly involved, or in the CPA (4 cases). These findings are concordant with what has been reported in the literature with nine out of 29 (31%) previously reported cases of schwannomas with calcification presenting as spinal cord masses, most often the thoracic spine, and nine (31%) arising in the CPA/vestibular nerves/internal auditory canal . Of the 10 cases with calcification in our cohort presenting in the spinal region, seven harbored dystrophic calcification, five had psammomatous calcification, and two contained both dystrophic and psammomatous calcifications.…”

“…The first case documenting calcification in schwannomas was published in 1961 by Lombardi and Passerini who described calcifications in spinal tumors radiologically detected . In the interim, only single case reports and rare small series have documented dystrophic and/or psammomatous calcification or ossification in schwannomas . Furthermore, the two series available describe two cases each and are limited to vestibular schwannomas .…”

Retroperitoneal schwannoma: an unusual cause of abdominal distention

“…CT and MRI findings show characteristic features such as a well-demarcated, homogeneous, spherical, solitary mass, but none are specific 1. Secondary degenerative changes, including cyst formation, calcification, haemorrhage and hyalinisation, can occasionally occur 2. This was also seen in our patient, where a large heterogeneous mass with areas of necrosis was seen on imaging.…”

“…Preoperative diagnosis is challenging and a definitive diagnosis can only be made postoperatively by histopathological and immunohistochemical analyses of surgical specimens. Benign retroperitoneal schwannomas generally have good prognosis after complete resection with a low risk of tumour recurrence 2. Schwannomas should be included in the differential diagnosis of any retroperitoneal abdominal mass.…”

Schwannoma in the hepatoduodenal ligament: A case report and literature review

“…They can arise almost anywhere, although the head, neck and extremities are the most common sites[10]. In the abdominal cavity, the retroperitoneum (6% of primary retroperitoneal tumors)[11] and stomach[12] are the most frequently involved sites. However, schwannomas in the ligaments[13], bowel mesentery[14] and abdominal organs including the gallbladder[15], pancreas[16] and liver[17] are rare.…”