Diagnosis Of Nerve Sheath Tumor Research Articles

Phantom limb pain, traumatic neuroma, or nerve sheath tumor? Illustrative case.

Phantom limb pain and traumatic neuromas are not commonly seen in neurosurgical practice. These conditions can present with similar symptoms; however, management of traumatic neuroma is often surgical, whereas phantom limb pain is treated with conservative measures. A 77-year-old female patient with a long-standing history of an above-the-knee amputation experienced severe pain in her right posterior buttocks area for several years' duration, attributed to phantom limb pain, which radiated down the stump of her leg and was treated with a variety of conservative measures. A recent exacerbation of her pain led to a prolonged hospitalization with magnetic resonance imaging of her leg stump, revealing a mass in the sciatic notch, at a relative distance from the stump. The anatomical location of the mass on the sciatic nerve in the notch led to a presumed radiological diagnosis of nerve sheath tumor, for which she underwent excision. At surgery, a neuroma of the proximal portion of the transected sciatic nerve that had retracted from the amputated stump to the notch was diagnosed. Traumatic neuromas of transected major nerves after limb amputation should be considered in the differential diagnosis of phantom limb pain.

Loss of H3K27me3 expression in canine nerve sheath tumors.

Nerve sheath tumors (NSTs) are characterized by neoplastic proliferation of Schwann cells, perineurial cells, endoneurial and/or epineurial fibroblasts. Diagnosis of NST is often challenging, particularly in distinguishing malignant NST (MNST) from other soft tissue sarcomas, or sometimes between low-grade MNST and benign NST. Recent studies in human pathology have demonstrated loss of trimethylation at lysine 27 of histone 3 (H3K27me3) in a subset of MNSTs using immunohistochemistry. Loss of H3K27me3 expression is rare in other high-grade sarcomas and also appears to be useful in distinguishing benign and low-grade MNSTs from high-grade subsets. In our retrospective study, we performed H3K27me3 immunohistochemistry in 68 canine tumors previously diagnosed as NST. We detected loss of H3K27me3 expression in 25% (n = 17) of all canine NST, including one neurofibroma, whereas 49% (n = 33) of tumors had mosaic loss of expression and 26% (n = 18) retained expression. No statistically significant differences were found between H3K27me3 expression, histopathological features of tumors, and their immunoreactivity for Sox10, claudin-1, GFAP, and Ki67. Because the classification of canine NST is not yet fully established and its correlation with the prognosis and clinical course of the disease is lacking, prospective studies with possible genetic analyses are needed to assess the true diagnostic value of H3K27me3 loss in canine NST.

Histopathological and Immunohistochemical Evaluation of Canine Nerve Sheath Tumors and Proposal for an Updated Classification.

Nerve sheath tumors are a group of tumors originating from Schwann cells, fibroblasts, and perineurial cells. In veterinary pathology, the terminology for nerve sheath tumors remains inconsistent, and many pathologists follow the human classification of such tumors in practice. Immunohistochemistry plays an important role in the diagnosis of nerve sheath tumors, but specific immunohistochemical and molecular biomarkers are lacking. In our study, we histopathologically reevaluated 79 canine nerve sheath tumors and assessed their reactivity for the immunohistochemical markers Sox10, claudin-1, GFAP, CNPase, and Ki-67. Based on the results, we classified the tumors according to the most recent human classification. Twelve cases were diagnosed as benign nerve sheath tumors, including six neurofibromas, three nerve sheath myxomas, two hybrid nerve sheath tumors (perineurioma/neurofibroma and perineurioma/schwannoma), and one schwannoma. Sixty-seven tumors were malignant nerve sheath tumors, including fifty-six conventional, four perineural, one epithelioid malignant nerve sheath tumor, and six malignant nerve sheath tumors with divergent differentiation. We believe that with the application of the proposed panel, an updated classification of canine nerve sheath tumors could largely follow the recent human WHO classification of tumors of the cranial and paraspinal nerves, but prospective studies would be needed to assess its prognostic value.

Case Report on Incidental Diagnosis of Nerve Sheath Tumor in a Patient with Thigh Pain and Back Pain

Case Report on Incidental Diagnosis of Nerve Sheath Tumor in a Patient with Thigh Pain and Back Pain

Tumors displaying hybrid schwannoma and neurofibroma features in patients with neurofibromatosis type 2.

Although schwannoma and neurofibroma tumors are generally reported as distinct pathologic diagnoses, sporadic schwannoma/neurofibroma hybrid nerve sheath tumors have been reported in the general population with components of both entities. We report the clinicopathological features of these hybrid nerve sheath tumors in patients with neurofibromatosis type 2 (NF2). A retrospective review of nerve sheath tumor surgical specimens from patients with NF2 enrolled at the National Institutes of Health was performed. Those specimens reported to have schwannoma-like and neurofibroma-like features were selected for further characterization by morphology, immunohistochemical panel (CD34, S100, neurofilament triplet protein (immunostain) (NFTP), epithelial membrane antigen (EMA)), and confirmation as hybrid tumors. Of 43 total NF2 patients undergoing resection of nerve sheath tumors, 11 specimens from 11 (26%) patients were found to be benign nerve sheath tumors exhibiting hybrid features of both neurofibroma and schwannoma. Immunohistochemical studies showed the schwannoma component to be S100+, CD 34- while the neurofibroma component was CD34+, variable S100+. Our experience emphasizes the importance of including this distinct tumor subtype, the schwannoma/neurofibroma hybrid tumor, in the differential diagnosis of nerve sheath tumors in NF2 patients and suggests that the relationship between neurofibroma and schwannoma tumors is closer than previously suspected.

Retraction Note to: CT and MR findings in a neuroforaminal extraskeletal Ewing sarcoma mimicking benign nerve sheath tumor

We report the CT and MR findings in a 30-year-old man with extraskeletal Ewing sarcoma (EES) involving the left neural foramen at L5–S1 level. The patient was evaluated with preoperative lumbosacral CT and MR imaging and postoperative lumbosacral MR imaging. The lesion was hyperdense on CT, isointense on T1- and T2-weighted MR images, and enhanced homogeneously after intravenous gadolinium injection. With these CT and MR findings, surgery was performed with a presumptive diagnosis of nerve sheath tumor, but the histopathological examination revealed EES. Chemotherapy and radiotherapy were planned postoperatively. This case illustrates that even in benign looking lesions in a neuroforamen one can never exclude malignancy, and this is even more true in a population of young adults.

Lost in Translation: Ambiguity in Nerve Sheath Tumor Nomenclature and Its Resultant Treatment Effect

There is much ambiguity surrounding the diagnosis of nerve sheath tumors, including atypical neurofibroma and low-grade MPNST, and yet, the distinction between these entities designates either benign or malignant behavior and thus carries presumed profound prognostic importance that often guides treatment. This study reviews the diagnostic criteria used to designate atypical neurofibroma from low-grade MPNSTs and reviews existing literature the natural history of each of these tumors to see if the distinction is, in fact, of importance.

RETRACTED ARTICLE: CT and MR findings in a neuroforaminal extraskeletal Ewing sarcoma mimicking benign nerve sheath tumor

We report the CT and MR findings in a 30-year-old man with extraskeletal Ewing sarcoma (EES) involving the left neural foramen at L5-S1 level. The patient was evaluated with preoperative lumbosacral CT and MR imaging and postoperative lumbosacral MR imaging. The lesion was hyperdense on CT, isointense on T1- and T2-weighted MR images, and enhanced homogeneously after intravenous gadolinium injection. With these CT and MR findings, surgery was performed with a presumptive diagnosis of nerve sheath tumor, but the histopathological examination revealed EES. Chemotherapy and radiotherapy were planned postoperatively. This case illustrates that even in benign looking lesions in a neuroforamen one can never exclude malignancy, and this is even more true in a population of young adults.

HEMANGIOMAS OF THE BRACHIAL PLEXUS

Hemangiomas of the brachial plexus are very rare, and there has not been a collection of multiple cases published in the literature to date. Extraneural brachial plexus hemangiomas typically present with similar signs and symptoms as nerve sheath tumors, including pain, paresthesia, and occasionally weakness, in addition to nonspecific imaging findings, making their diagnosis difficult. Exploratory surgery can lead to significant bleeding and nerve injury when a hemangioma or an associated aneurysm is encountered intraoperatively. We present 5 cases of extraneural hemangiomas causing brachial plexopathy, including pre-, intra-, and postoperative decision making, with an emphasis on diagnostic and management issues as well as outcomes. A retrospective review was performed of 5 patients who underwent surgery at a university teaching hospital between 1995 and 2007 for exploration of brachial plexus lesions that were confirmed to be hemangiomas at pathological examination. All 5 patients presented with findings on history, physical examination, imaging, and electromyography suggesting a diagnosis of nerve sheath tumor. Two patients had biopsies (1 needle, 1 open), both of which were nondiagnostic. Three patients underwent digital subtraction angiography with successful preoperative embolization. Each patient had a complete or a radical subtotal tumor resection, and all were intact neurologically after surgical resection. Pathological evaluation identified 3 venous hemangiomas, 1 hemangioma with arteriovenous malformation features, and 1 Masson hemangioma associated with a large aneurysm. Extraneural hemangiomas of the brachial plexus are very rare, but a high index of suspicion and appropriate preoperative evaluation, including angiography with the option for embolization, can result in decreased intraoperative hemorrhage and better patient outcomes.

An uncommon type of adrenal incidentaloma: a case report of a schwannoma of the adrenal medulla with cytological, histological, and ultrastructural correlation

Benign nerve sheath tumors of the adrenal gland are an extremely uncommon cause of an incidentaloma. We report a case of a schwannoma of the adrenal medulla in an asymptomatic 51-year-old woman, which was discovered incidentally on a computed tomography scan after routine workup for her degenerative joint diseases of the lumbar spine. Because of the large size and unknown biologic nature of the tumor by clinical and radiographic studies alone, an adrenalectomy was performed. The gross specimen featured a well-circumscribed medullary based tumor with cystic degeneration. The diagnosis of a nerve sheath tumor was based on classic histological findings, supported by S-100 positivity, and ultrastructurally by the finding of typical Schwann cells. The cytological diagnosis from the fine-needle aspiration biopsy material obtained at the time of gross examination was much more challenging on retrospective review. The aspirated material showed a round- to oval-cell predominant smear with occasional striking anisonucleosis, intranuclear inclusions (so-called ancient change), and pigment deposition. A review of the histogenesis and differential diagnosis of this common nerve sheath tumor in this unusual location is discussed.