Schwannoma of the psoas: An unusual cause of abdominal pain

Laparoscopic resection of retroperitoneal intra-psoas muscle schwannoma: A case report and extensive literature review

“…Most often, and like in our patient, incidental and delayed diagnosis of retroperitoneal mass is made which is most probably related to vague symptoms and large and flexible retroperitoneal space [ 2 , 3 ]. The differential diagnosis of retroperitoneal mass includes the following: benign (schwannomas, paragangliomas, angiomyolipoma), lymphoproliferative (Hodgkin’s), epithelial (kidney, adrenal, pancreas), metastatic (germ cell tumor, melanoma), pheochromocytoma, sarcoma (liposarcoma, leiomyosarcoma), and malignant fibrous histiocytoma [ 1 , 6 ].…”

“…The malignant transformation is extremely rare except in the presence of type 2 neurofibromatosis which ranges from 5 to 18%. The clinical manifestation is significantly nonspecific, mainly depending on the size and location of the mass [ 1 , 2 ]. Till date, there is no real incidence or summary concerning what is reported in the literature about intra-psoas muscle schwannoma.…”

“…If retroperitoneal tumors are suspected, MRI is highly recommended which offers a better delineation of the origin, extent, and internal composition of these lesions [ 3 , 6 ]. MRI is the gold standard image to establish the diagnosis of retroperitoneal schwannoma demonstrated as hypointense on T1 (Antoni type A tissue) and hyperintense on T2 (hypocellular Antoni B tissue) weighted MR images [ 2 , 3 ]. Schwannoma which is characterized by the presence of solid-cystic characteristics and degenerative histological changes, typical as in our case, is called ancient schwannoma.…”

“…Soft tissue tumors of Schwann cells in either the peripheral or cranial nerves are known as schwannomas or also as neurilemmomas. They predominantly affect female patients from the third to the fifth decade of life with a highly nonspecific presentation [ 1 , 2 ]. They are rare tumors and retroperitoneal types are even rarer (only 0.3–3%, except in cases of von Recklinghausen’s disease), especially schwannoma of psoas muscle which is extremely rare, showing limited reported cases worldwide with rarely malignant transformation [ 3 , 5 ].…”

“…They are rare tumors and retroperitoneal types are even rarer (only 0.3–3%, except in cases of von Recklinghausen’s disease), especially schwannoma of psoas muscle which is extremely rare, showing limited reported cases worldwide with rarely malignant transformation [ 3 , 5 ]. The cornerstone in the management of retroperitoneal schwannomas is complete surgical excision as it is nonsensitive to radiation and chemotherapy [ 2 , 3 ]. This project has been reported in line with the SCARE criteria [ 8 ].…”