Epithelioid angiosarcoma arising in schwannoma of the kidney: report of the first case and review of the literature

Abstract

BackgroundSchwannoma and angiosarcoma are infrequent pathologies that have been rarely reported in the kidney. Angiosarcoma is an uncommon malignant tumor presenting a recognizable vascular differentiation. It can develop in any site but the most common locations include the skin, soft tissues, breast, bone, liver, and spleen while renal localization has been very rarely reported in the literature. Schwannoma is a benign peripheral nerve sheath tumor composed of cells with the immunophenotype and ultrastructural features of differentiated Schwann cells. It has a wide anatomical distribution but the most frequent locations include subcutaneous tissues of the extremities and the head and neck region and the retroperitoneal and mediastinal soft tissues. The occurrence of an angiosarcoma in a pre-existing schwannoma is an extremely rare event with <20 cases reported in worldwide literature. In the present study, a renal case of angiosarcoma arising in schwannoma is presented with a detailed review of the pertinent literature.Case PresentationA 56-year-old man was admitted with a few days history of lower back pain and hematuria. Abdominal ultrasound showed a mass inside the left renal medulla. Subsequent imaging investigations with computed tomography and magnetic resonance confirmed the presence of the lesion and showed a pulmonary metastasis.ConclusionsThe final histopathological examination led to the diagnosis of epithelioid angiosarcoma arising in a schwannoma. The patient came to death a few months later due to a massive hemothorax. To the best of our knowledge, the present is the first case of an angiosarcoma arising in a schwannoma of the kidney.

Robot-Assisted Laparoscopic Renal Schwannoma Excision

“…This CT scan finding is consistent with other renal schwannomas reported in the literature. 2 Our patient did not have an MRI; however, it has been reported that MRI of these tumors reveals isointensity on T1-weighted images and high signal intensity on T2-weighted images. It has also shown on Gadolinium-enhanced T1-weighted images to reveal homogeneous enhancement in solid components of the tumor.…”

“…The majority of tumors are located in the parenchyma rather than the hilum. 3 The average size of these tumors has been reported to be 10 cm, 2 but analysis of cases since 2001 revealed a decrease in median size to 6.5 cm. This decrease in size is likely attributed to the increased utilization of CT imaging within the population.…”

“…It has also shown on Gadolinium-enhanced T1-weighted images to reveal homogeneous enhancement in solid components of the tumor. 2 Unfortunately this has not been shown to differentiate between benign and malignant renal schwannomas. Shun-Fa and colleagues.…”

“…1 Renal (or retroperitoneal) schwannomas are rare and were first described in 1955. 2 Approximately 25 cases of renal schwannoma have been described in the literature. Renal schwannomas are predominately a benign tumor, but reports of malignant features have been reported.…”

“…Iannaci et al recently reported a case of epithelioid angiosarcoma arising within a renal schwannoma. 2 Unfortunately, radiographic imaging of these tumors cannot differentiate between benign renal schwannomas and malignant tumors. Diagnosis of a renal schwannoma is usually made at time of pathologic examination.…”