Abdominal schwannomas: review of imaging findings and pathology

Abstract

Schwannomas are typically slow growing, encapsulated benign neoplasms. Visceral schwannomas are rare, and preoperative diagnosis is challenging, as they are often confused with other neoplasms even with advanced imaging studies. Surgical excision is usually needed to establish a definitive diagnosis, as pathology is the "gold standard." We review the imaging findings of abdominal schwannomas focusing on pancreatic, gastrointestinal, and retroperitoneal/adrenal schwannomas with pathology correlation. We conclude that schwannoma should be included in the broad differential diagnosis of an abdominal mass and that when it is unnecessary radical resection can be avoided.

Sonographic appearances of adrenal schwannomas

“…Compared with their counterparts arising in the head and neck or extremities, retroperitoneal schwannomas have a higher tendency to undergo spontaneous cystic degeneration . Cystic change is also the major feature of primary adrenal schwannoma, which usually can be detected on CT and MRI . In the present study, two types of intralesional cystic areas were found in the 11 cases, and a multiseptated cystic appearance was the most frequent form.…”

“…In the present study, two types of intralesional cystic areas were found in the 11 cases, and a multiseptated cystic appearance was the most frequent form. Although the appearance of cystic change on CT and MRI has been reported, this is the first detailed US description of the different forms of cystic change of adrenal schwannomas.…”

“…15 On MRI, adrenal schwannomas have been described as a mass with low signal intensity on T1-weighted images and heterogeneous high signal intensity on T2-weighted images. 15,22 US findings have only been addressed in a few case reports. 4,11,20 As previously reported, adrenal schwannoma usually appears as a well-demarcated, homogeneous, hypoechoic mass.…”

“…The usual CT appearance of adrenal schwannoma is that of a well‐defined unilateral mass with cystic degeneration, with a characteristic, progressive contrast‐enhanced pattern after contrast injection . On MRI, adrenal schwannomas have been described as a mass with low signal intensity on T1‐weighted images and heterogeneous high signal intensity on T2‐weighted images . US findings have only been addressed in a few case reports .…”

Giant posterior pararenal schwannoma: A�case report and review of literature

“…For retroperitoneal masses larger than 4 cm, especially those with clinical symptoms, surgical removal is regarded as the most rational way, with the benefit of both diagnosis and therapy. An incomplete excision may increase 5-10% of local recurrence (7). Moreover the possibility of malignancy is considerable.…”