Primary hepatic schwannoma: A case report

A Rare Case of Hepatic Schwannoma in the Setting of Schwannomatosis

Schwannomas are benign nerve sheath tumors commonly found in the head, neck, vestibular system, and extremities. Primary hepatic schwannomas are exceptionally rare, with 34 cases reported to date according to our review of the literature. This case report describes a 79-year-old man with a medical history of skin and thyroid cancer, who presented with no clinical symptoms and underwent a follow-up MRI due to an initial scan indicating a suspicious hepatic mass resembling an atypical hemangioma. The MRI revealed a 3.6 cm left hepatic mass concerning for an intrahepatic cholangiocarcinoma. Histopathological and immunohistochemical studies of a biopsy of the liver mass confirmed the presence of a benign hepatic schwannoma. Further evaluation revealed multiple spinal schwannomas, leading to the diagnosis of schwannomatosis. The diagnosis of hepatic schwannomas poses challenges through imaging alone. This case underscores the importance of microscopic evaluation in accurately diagnosing hepatic masses. Additionally, the presence of concurrent schwannomas should be considered in patients initially diagnosed with isolated schwannomas.

Primary Hepatic Schwannoma: Case Report and Literature Review

Primary hepatic schwannoma is an extremely rare tumor with a good prognosis. Preoperative diagnosis is often challenging due to nonspecific clinical symptoms and its rarity. Here, we report a case of a 56-year-old male patient misdiagnosed with malignant liver tumor, later identified as primary hepatic schwannoma. Furthermore, clinical and histopathological features of 19 cases of primary hepatic schwannoma are also documented. The age of the patients ranged from 38 to 72 years, with a mean age of 56.4 years, and the disease was more common in females. Patients typically presented without clinical symptoms and were not associated with neurofibromatosis type 1. Histopathological features of the tumor were similar to soft tissue schwannoma, characterized by a thick capsule consisting of Antoni A and Antoni B areas. Immunohistochemically, the tumor showed strong positivity and diffusely stained with S-100, while being negative for CD34, CD117, and SMA. Complete resection of the tumor was achieved in all patients. The prognosis was favorable, with no signs of recurrence. Follow-up examinations revealed disease-free survival ranging from 6 to 27 months. Differential diagnosis of primary hepatic schwannoma from malignant liver tumors and metastatic liver tumors can be made based on histopathological features and immunohistochemical staining with S-100.

Schwannoma in and around the porta hepatis: radiological features in eight cases and literature review

PURPOSE

Schwannomas in and around the porta hepatis (porta hepatic schwannomas) are rare benign tumors easily misdiagnosed as other pathologies, including malignancies. We aimed to evaluate their imaging features on ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), and ¹⁸F-fluorodeoxyglucose-positron emission tomography/CT (FDG-PET/CT).

METHODS

We performed a multi-institutional retrospective study by reviewing the clinical and imaging findings of pathologically proven eight porta hepatic schwannomas (mean age, 55 years; range, 38-80 years; one male and seven females). Preoperative imaging included three ultrasonography, eight CT, eight MRI, and two FDG-PET/CT.

RESULTS

All patients were asymptomatic. The mean tumor size was 61.9 mm (range, 30-180 mm), and all tumors demonstrated well-defined lesions on ultrasonography and their solid components showed soft tissue attenuation on non-contrast CT. MRI showed two distinct components in all cases: the component with T1-weighted hypointensities and T2-weighted hyperintensities with poor enhancement (suggestive of Antoni B histology); the component with T2-weighted hypointensities with gradually increasing enhancement (suggestive of Antoni A histology), resulting in a heterogeneous pattern on post-contrast CT or MRI (8/8, 100%). The separated deviation of surrounding bile ducts and vessels without obstruction allowed the recognition of extrahepatic localization and their benign nature. A ginger root-like morphology (2/8, 25%) seemed to be suggestive of extension along the Glisson's sheath, although this finding was not seen frequently.

CONCLUSION

Recognizing imaging features such as extrahepatic location, benign nature with internal structures suggestive of Antoni A/B histology, and characteristic tumor extension may provide key diagnostic clues for porta hepatic schwannomas.

MR imaging features of pancreatic schwannoma: a Chinese case series and a systematic review of 25 cases

BACKGROUND

There is a paucity of existing literature centering on the magnetic resonance (MR) imaging features of pancreatic schwannomas, due to the neoplasm's nonspecific presentation and its rarity. We aimed to identify the characteristic imaging features of pancreatic schwannoma.

METHODS

This retrospective search was conducted for histologically confirmed pancreatic schwannoma in multi-institutional database of pathology. Abdominal magnetic resonance imaging (MRI) was performed before histologic examination and their MR imaging studies were independently reviewed. The search yielded six adults (mean age, 46 years) with a definitive histologic postoperative diagnosis of single pancreatic schwannoma each. Additionally, a comprehensive English and Chinese literature review for pancreatic schwannoma and reported MR-imaging findings since 1961 was also conducted. MR imaging features of those cases in the literature were analyzed, summarized and compared with our case series.

RESULTS

This rare entity appeared to be a well-circumscribed, exophytic, oval or round pancreatic mass with a mean greatest diameter of 3.7 cm. Five schwannomas were located in the pancreatic head-neck and one in the pancreatic tail. On MRI, all cases appeared hypointense on T1-weighted images, inhomogeneous hyperintense on T2-weighted images, and hyperintense on diffusion-weighted images. The mean apparent diffusion coefficient (ADC) values of pancreatic schwannoma were 1.11 ± 0.29 × 10- 3 mm2/s and significantly lower than the surrounding pancreas. The lesion-to-pancreas signal intensity ratio (SIR) at unenhanced T1-weighted images was 0.53 ± 0.07. On dynamic contrast-enhanced MRI, most of the lesions (67%, 4/6) showed homogeneously iso- or hypointense on arterial and portal venous phases, and hyperenhancement on delayed phase compared with the surrounding pancreas. In our analysis of the time intensity curves, all cases exhibited a gradual enhancement pattern.

CONCLUSIONS

A well-circumscribed mass displaying inhomogeneous hyperintensity on T2, marked hypointensity on T1, hyperintensity on DWI, and with early slight enhancement at arterial phase and progressive enhancement at portal venous and delayed phase, may suggest the diagnosis of pancreatic schwannoma.

Retroperitoneal schwannoma preoperatively diagnosed as liver metastasis from colon cancer: A case report

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Retroperitoneal schwannomas are very rare and difficult to make a definite diagnosis.

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This is the first report of surgery for colon cancer and retroperitoneal schwannoma performed simultaneously.

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Although liver lesions accompanied by advanced malignant tumor should be firstly considered as liver metastasis, other rare tumors are also occasionally seen.

Background

Retroperitoneal schwannomas are rare.

Case presentation

We here report a case of 64-year-old woman who was referred to her local hospital for abdominal pain and found to have a palpable tumor. Computed tomography (CT) and colonoscopy revealed a combination of liver and colon lesions and colon cancer with a large liver metastasis was suspected. After neoadjuvant chemotherapy had proved ineffective for her presumed liver metastasis, the patient was referred to our hospital where we performed a simultaneous right hemicolectomy and extended left hepatic lobectomy. The pathological diagnoses were a colonic adenocarcinoma and retroperitoneal schwannoma immediately adjacent to the liver.

Conclusions

Although liver metastasis should be the first provisional diagnosis in patients with advanced colon cancer, retroperitoneal schwannoma should also be suspected in the differential diagnosis of possible liver lesions.

[Primary Hepatic Schwannoma]

A primary benign schwannoma of the liver is extremely rare. Only 30 cases have been reported in the medical literature worldwide, and only one case has been reported in Korea previously. A 56-year-old man was admitted to Gil Medical Center with incidental findings of a hepatic mass by abdominal computed tomography. The computed tomography and magnetic resonance image revealed a 3×2 cm-sized solid mass in the left lobe of the liver. Histological examination confirmed the diagnosis of a benign schwannoma, proven by positive immunoreaction with the neurogenic marker S-100 protein and a negative response to CD34, CD117, and smooth muscle actin. We report a primary benign schwannoma of the liver and review the literature.