Intravascular schwannoma as an extremely unusual cause of vein obstruction: a case report.

The blood vessel lumen is an extremely rare location for a benign peripheral nerve sheath tumor like schwannoma. Less than 10 cases have been previously reported. In this report, we present a case of a 68-year-old woman who had a soft tissue nodule at the posterior calf of her left leg during a physical examination. Pathological examination was performed after complete surgical excision. The patient underwent follow-up for 12 months after surgery without evidence of recurrence or any other complication. This is the first case of intravascular schwannoma reported as a cause of vein obstruction. Microscopically, the tumor was composed of Schwann spindle cells that were immunoreactive for S100 protein and SOX10. This tumor was surrounded by a well-defined vascular smooth muscle wall. Prospective series are required to improve the knowledge on the underlying mechanisms of intravascular schwannoma development.

A Rare Case of a Schwannoma on the Foot - Case Report.

A Schwannoma is an infrequent lesion. This tumor derives from the myelin sheath of the peripheral nerves; in most cases, it is benign and rarely presents in the foot and ankle region. Patients affected by this type of pathology are usually asymptomatic. Still, they sometimes have sensory or motor neurologic symptoms if the tumor is large enough to cause direct or indirect compression of the affected nerve. A 55-year-old male patient presented to our department with non-traumatic swelling and pain in the lateral aspect of the right foot and leg. A magnetic resonance imaging (MRI) scan of the right leg revealed a well-circumscribed lesion, measuring 2,5 by 1 cm, showing hypointensity on T1 sequences and hyperintensity on T2, compatible with a superficial peroneal nerve sheath cells tumor. Surgical excision of the lesion was performed, and the histopathological examination confirmed the initial suspicion-Schwannoma of the superficial peroneal nerve. The postoperative period was uneventful, with progressive improvement of pain and complete functional recovery without neurological deficits. Rigorous clinical examination associated to MRI scans allow adequate diagnosis as well as the exclusion of other pathologies with similar clinical presentation. Thus, the surgeon has to be aware of all the data for an effective diagnosis and treatment in this type of rare pathology that cannot be neglected.

Hybrid peripheral nerve sheath tumours: MRI features with pathological correlation in 24 cases.

OBJECTIVES: To describe the MRI features of histologically proven hybrid peripheral nerve sheath tumours (HPNST). METHODS: A retrospective analysis of the MRI features of 24 histologically proven cases of HPNST over 7 years. Demographic data obtained from clinical records included age, gender, and date of diagnosis. Two readers independently assessed MRI studies and assessed the following features: involvement of a major nerve, intramuscular location, lesion morphology, entering nerve sign, exiting nerve sign, target sign, fascicular sign, split fat sign, and ancient change (cystic change). Inter-observer agreement was assessed with Cohen's kappa coefficient. Histological diagnosis was based on either image-guided needle biopsy or resection histology. RESULTS: The study included 9 males and 15 females with mean age 50 years (range: 24-78 years). Nine tumours (35%) involved a major nerve including spinal roots (5), radial (1), median (1), tibial (1), and axillary (1), while 5 (21%) tumours were intramuscular. The mean tumour size was 4.2 cm (standard deviation of 2.4 cm). The frequency of MRI features was as follows: lobular contour (71%; 17/24), ancient change (38%; 9/24), fascicular sign (17%; 4/24), entering nerve sign (21%; 5/24), exiting nerve sign (13%; 3/24), target sign (13%; 3/24), and split fat sign (8%; 2/24). Inter-observer agreement was high, ranging from 0.7 to 0.83. CONCLUSIONS: HPNST infrequently demonstrate the classical MRI signs of benign peripheral nerve sheath tumours, but commonly have a lobular morphology and can show ancient/cystic change. ADVANCES IN KNOWLEDGE: This is the first study in the literature analysing the MRI features of histologically proven HPNST. HPNST infrequently shows the classical MRI signs that would be expected with benign peripheral nerve sheath tumours although commonly have a lobular morphology and show cystic change.

A rare case of intraoral schwannoma in gingiva.

BACKGROUND: Schwannomas are benign, slow-growing encapsulated nodular lesions. As for the most benign encapsulated lesions, the treatment of choice is complete removal of the entire tissue with preservation of surrounding tissue. METHODS AND RESULTS: The case presented is that of a 35-year-old female with the chief complaint of swelling on her gums in the lower left posterior region. Through intraoral and extraoral examinations the benign nature of the lesion was established. The excisional biopsy was carried out under local anesthesia, and the specimen was sent for histological examination, which gave a definite diagnosis of oral schwannoma. The patient was recalled at regular intervals so as to check for any recurrence of the lesion or occurrence of new lesions elsewhere in the body. CONCLUSION: The present case reemphasizes the importance of thorough clinical examination along with appropriate investigations, especially histopathological and immunohistochemical, for establishing a definitive diagnosis, which eventually plays an important role in the choice and execution of appropriate treatment at the earliest for the best prognosis and outcomes. KEY POINTS: Why is this case new information? To the best of the author's knowledge, this the first case report of oral schwannoma diagnosed in gingiva in Indian population. This case presented a diagnostic dilemma due to its unusual location. What are the keys to successful management of this case? Schwannomas when completely excised have low rate of recurrence. Accurate diagnosis of the lesion along with complete physical examination and follow-up at regular interval to rule out any recurrences are the keys to successful management of this case. What are the primary limitations to success in this case? Lack of data regarding residual tumor postoperative is a primary limitations to success of the case, as recurrence is associated with subtotal tumor removal.

Cytological features of cranial and paraspinal nerve Tumours.

The 2021 World Health Organization Classification of Central Nervous System Tumours introduced significant revisions to the categorization of paraspinal and nerve sheath tumours. This updated system encompasses seven tumour types: schwannoma, neurofibroma, perineurioma, hybrid nerve sheath tumours, malignant melanotic nerve sheath tumour, malignant peripheral nerve sheath tumour and cauda equina neuroendocrine tumour. This review provides an image-rich cytologic reference of these tumours, with particular emphasis on intraoperative smear preparations. Knowledge of the key cytological features of these tumours and their differential diagnoses will help guide classification of these challenging entities.

Intraoral Cellular Schwannoma Involving Maxillary Gingiva: A Rare Case Report.

Oral schwannomas (OSs) are uncommon benign nerve sheath tumors accounting for 1% of all schwannomas and may arise from either soft tissue or bone. Cellular schwannoma is a rare histological variant of schwannoma which is characterized by increased cellularity. The most common intraoral site of occurrence is the tongue followed by the floor of the mouth and palate. Here, we are reporting a rare case of intraoral cellular schwannoma involving both facial and palatal gingiva of the right maxilla in a young Indian male patient.

Perineurioma Diagnosed After Endoscopic Treatment of Suspected Gastric Adenocarcinoma of the Fundic Gland.

Perineurioma is a relatively rare tumor with an occasionally difficult differential diagnosis. A 63-year-old woman underwent esophagogastroduodenoscopy, which revealed a 15 mm, slightly faded, flat, and elevated lesion in the gastric body. Biopsy revealed a bundle-like proliferation of spindle-shaped cells; however, the diagnosis was unconfirmed. Endoscopic submucosal dissection was performed for diagnosis and treatment. Histopathological examination of the lesion revealed cell proliferation with short spindle-shaped and oval nuclei and little atypia in the lamina propria. Immunohistochemical examination indicated a perineurioma. Thus, when spindle-shaped cells are found on biopsy, it is necessary to consider the possibility of perineurioma.

Imaging in gynecological disease (26): clinical and ultrasound characteristics of benign retroperitoneal pelvic peripheral-nerve-sheath tumors.

OBJECTIVE: To describe the clinical and sonographic characteristics of benign, retroperitoneal, pelvic peripheral-nerve-sheath tumors (PNSTs). METHODS: This was a retrospective study of patients with a benign, retroperitoneal, pelvic PNST who had undergone preoperative ultrasound examination at a single gynecologic oncology center between 1 January 2018 and 31 August 2022. All ultrasound images, videoclips and final histological specimens of benign PNSTs were reviewed side-by-side in order to: describe the ultrasound appearance of the tumors, using the terminology of the International Ovarian Tumor Analysis (IOTA), Morphological Uterus Sonographic Assessment (MUSA) and Vulvar International Tumor Analysis (VITA) groups, following a predefined ultrasound assessment form; describe their origin in relation to nerves and pelvic anatomy; and assess the association between their ultrasound features and histotopography. A review of the literature reporting benign, retroperitoneal, pelvic PNSTs with preoperative ultrasound examination was performed. RESULTS: Five women (mean age, 53 years) with a benign, retroperitoneal, pelvic PNST were identified, four with a schwannoma and one with a neurofibroma, of which all were sporadic and solitary. All patients had good-quality ultrasound images and videoclips and final biopsy of surgically excised tumors, except one patient managed conservatively who had only a core needle biopsy. In all cases, the findings were incidental. The five PNSTs ranged in maximum diameter from 31 to 50 mm. All five PNSTs were solid, moderately vascular tumors, with non-uniform echogenicity, well-circumscribed by hyperechogenic epineurium and with no acoustic shadowing. Most of the masses were round (n = 4 (80%)), and contained small, irregular, anechoic, cystic areas (n = 3 (60%)) and hyperechogenic foci (n = 5 (100%)). In the woman with a schwannoma in whom surgery was not performed, follow-up over a 3-year period showed minimal growth (1.5 mm/year) of the mass. We also summarize the findings of 47 cases of benign retroperitoneal schwannoma and neurofibroma identified in a literature search. CONCLUSIONS: On ultrasound examination, no imaging characteristics differentiate reliably between benign schwannomas and neurofibromas. Moreover, benign PNSTs show some similar features to malignant retroperitoneal tumors. They are solid lesions with intralesional blood vessels and show degenerative changes such as cystic areas and hyperechogenic foci. Therefore, ultrasound-guided biopsy may play a pivotal role in their diagnosis. If confirmed to be benign PNSTs, these tumors can be managed conservatively, with ultrasound surveillance. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

[Histological and molecular characteristics of tumours of the peripheral nervous system]. / Histologische und molekularpathologische Besonderheiten von Tumoren des peripheren Nervensystems.

Tumours of the peripheral nervous system occur sporadically in adults and except for a minority of entities, these tumours are usually benign. The most common are nerve sheath tumours. Because these tumours grow in direct proximity or even invade peripheral nerve bundles, they can lead to severe pain and motion deficits. From the neurosurgical perspective these tumours are technically challenging, and especially for tumours with an invasive growth pattern complete resection may not be possible. Peripheral nervous system tumours that are associated with tumour syndromes such as neurofibromatosis type 1 and 2 or schwannomatosis are a particular clinical challenge. The goal of the current article is to present histological and molecular characteristics of peripheral nervous system tumours. Furthermore, future targeted therapy strategies are presented.

Spermatic cord anastomosing hemangioma mimicking a malignant inguinal tumor: A case report and literature review.

Background: Anastomosing hemangioma (AH) is a rare vascular tumor and occurs in various organs. It is difficult to distinguish AH from malignant tumors even through multimodal imaging examination. AH located in the inguinal region is even rare. We present the diagnosis and treatment of a patient with spermatic cord AH in detail and conduct a literature review. Case Report: An 84-year-old Chinese man had swelling pain in his right scrotum. A hard and fixed mass was palpable in the right inguinal region. Preoperative radiological examination considered it a neurogenic or vascular tumor. Malignant soft tissue sarcoma could not be excluded. He underwent radical inguinal right orchiectomy under intraspinal anesthesia. The diagnosis of spermatic cord AH was confirmed by pathological examination. The patient recovered uneventfully and remained disease-free during an 18-month follow-up. Conclusion: Spermatic cord AH is quite rare and could be misdiagnosed as a malignant tumor. Pathological evidence might be necessary. The optimal choice of treatment should be determined through a comprehensive assessment of both tumor and patient factors.

A Rare Case of Bladder Perineurioma.

Perineuriomas are benign, rare neoplasms of the nerve sheath, basically in two forms: intraneural and extraneural. Extraneural forms are mainly found in the trunk and limbs, while visceral organs are rarely affected. To date, there have been no previous reports in the literature of bladder perineurioma. In this case, we report a young adult with hematuria and bladder tumor which after surgical resection and immunohistochemical study was confirmed to be a perineurioma. Therefore, this should be included in the differential diagnosis during the analysis of resections of bladder tumors.

Palisaded encapsulated neuroma on the lower lip: a case report.

Palisading encapsulated neuroma is a rare, benign, cutaneous nerve sheath tumor. It usually occurs as an asymptomatic solitary skin-colored papule and commonly affects the nose and cheeks. Sometimes, it involves other sites, including the shoulder, upper arm, and trunk, but rarely involves the oral mucosa, including that of the lip. In our case, a 63-year-old female patient complained of a pinkish rubbery nodule on her lower lip. Histopathologic examination demonstrated a well-circumscribed nodule encapsulated by connective tissue stroma in the dermis. The nodule consisted of palisading spindle-shaped tumor cells with wavy and basophilic nuclei. The cells were arranged in streaming fascicles with multiple clefts and were strongly positive for S-100 proteins. To our knowledge, only three cases of palisading encapsulated neuroma on the lower lip have been reported in the Korean literature. Herein, we report a rare case of an oral palisaded encapsulated neuroma.

Serendipitous Discovery of a Benign Obturator Nerve Schwannoma: Case report with a brief clinical review.

Schwannomas are typically benign tumours of the peripheral nerves. However, they seldom arise from the obturator nerve. We report a case of an uncommon swelling (2.5 × 3.5 cm) in a 65-year-old male cadaver, found during a routine dissection session for first Bachelor of Medicine and Surgery students in the Department of Anatomy, Kasturba Medical College, Manipal, India, in 2019. It was seen originating from the left obturator nerve in the pelvis at the level of the sacral promontory. Histopathological investigation revealed a schwannoma. The hypocellular tumour was arranged in a sweeping fascicle pattern with patches of myxoid degeneration. Obturator schwannomas, though rare, can exist in cadavers, as seen in the present case. Hence, it should be considered as a differential diagnosis for clinical cases of pelvic masses and eliminated only after thorough radiological examination. Knowledge about the existence of such schwannomas is therefore essential.

Intrinsic peripheral nerve and root tumor and pseudotumoral lesions at a tertiary care pediatric hospital.

PURPOSE: Tumors affecting peripheral nerves in children are rare. Accurate diagnosis ensures that management is appropriate and timely. A review of intrinsic nerve tumors was completed to differentiate common peripheral nerve lesions based on clinical characteristics and investigations. METHODS: A retrospective review was conducted for children (< 18 years old) diagnosed with an intrinsic tumor affecting peripheral nerve(s) or roots at the Children's Hospital of Eastern Ontario (CHEO) from 2009 to 2019. RESULTS: We report 14 children with perineurioma (N = 6), neurofibroma (N = 4), intraneural ganglion cyst (N = 2), or lipomatosis (N = 2). Mean age of symptom onset was 8.2 years (range 0.3 to 17.3 years). Presenting symptoms included muscle weakness (7/14), painless muscle wasting (2/14), contracture (1/14), pain (1/14), or the identification of a painless mass (3/14). Nerve conduction studies (NCS) or electromyography (EMG) were performed in 11/14 patients. MRI was useful at differentiating between these pediatric nerve tumors. Biopsies were performed in nine patients with additional surgical management pursued in four patients. CONCLUSION: The rare nature of peripheral nerve tumors in children can pose diagnostic challenges. NCS/EMG are important to assist with localization, and MRI is useful to distinguish more benign tumors. Key MRI, clinical, and NCS features can in some cases guide management, potentially avoiding the need for invasive procedures.

Epithelioid Sarcoma of the Peripheral Nerve: Clinicopathologic Series of Three Cases and Literature Review.

OBJECTIVES: Epithelioid sarcoma (ES) rarely arises in the nerve. To increase our understanding of this unusual tumor originating in the nerve, we describe the features of three cases and review the literature. METHODS: Clinical data, imaging, pathology, treatment, and follow-up are detailed. A systematic literature review was conducted. RESULTS: Two patients were male and one female; the median age was 24 years. The patients had neurologic symptoms, and the tumors arose in large nerves and ranged from 2.4 to 5.8 cm. The tumors were avid on positron emission tomography-computed tomography and showed increased signal intensity on T2-weighted magnetic resonance imaging. Centered in the nerve, the tumors grew with an infiltrative pattern and encased the nerve fascicles. All were treated with wide resection, and adjuvant treatment included combinations of chemotherapy and radiation. One recurred, and the limb was amputated. Metastases were documented to lymph nodes, lung, pleura, and skin. One patient died of disease after 54 months. Literature review including our cases showed that tumors stained with pancytokeratin (9/9), EMA (4/4), and CD34 (7/7); there was loss of INI1 in all six cases tested. CONCLUSIONS: ES rarely arises in the peripheral nerve, and its infiltrative nature often requires morbid surgery. The differential includes a variety of benign and malignant epithelioid neoplasms.

Malignant peripheral nerve sheath tumor in a child.

Among the diverse causes of posterior mediastinal masses, malignant peripheral nerve sheath tumors is a very rare neurogenic tumor. Imaging features tend to be variable. A 20-month-old toddler presented with a 3-month history of persistent diffuse thoracic and abdominal pain. A chest magnetic resonance imaging was taken and shown a posterior mediastinal lesion. Histopathology and immunohistochemical analysis confirmed the diagnosis of a malignant peripheral nerve sheath tumor with myxoid areas. Malignant peripheral nerve sheath tumors are an uncommon entity in the children with a poor prognosis. Magnetic resonance imaging is the preferred technique in children to limit the use of ionizing radiation and because has a higher contrast resolution; however, all suspicious tumors should be biopsied to make an appropriate diagnosis. Treatment is radical surgery with excision of the entire mass; however, there is a high incidence of local recurrence.

Diffusion tensor imaging and tractography for preoperative assessment of benign peripheral nerve sheath tumors.

PURPOSE: To evaluate the diagnostic value of fiber tractography and diffusivity analysis generated from 3D diffusion-weighted (DW) sequences for preoperative assessment of benign peripheral nerve sheath tumors. METHOD: MR imaging at 3 T was performed in 22 patients (mean age 41.9 ±â€¯17.1y, 13 women) with histologically confirmed schwannomas (N = 18) and histologically confirmed neurofibromas (N = 11), including a 3D DW turbo spin echo sequence with fat suppression. Diffusion tensor parameters were computed and fiber tracks were determined. Evaluation was performed by two radiologists and one orthopedic surgeon blinded for final diagnosis. Mean diffusivity was computed to allow further assessment of tumor microstructure. Preoperative fascicle visualization was graded, fascicles were categorized regarding anatomical location and amount of fascicles surrounding the tumor. The agreement of imaging findings with intraoperative findings was assessed. RESULTS: On 78.3 % of the DTI images, the fascicle visualization was rated as good or very good. Tractography differences were observed in schwannomas and neurofibromas, showing schwannomas to be significantly more often located eccentrically to the nerve (94.8 %) than neurofibromas (0 %, P < 0.01). Fascicles were significantly more often continuous (87.5 %) in schwannomas, while in neurofibromas, none of the tracks was graded to be continuous (0 %, P = 0.014). A substantial agreement between fiber tracking and surgical anatomy was found regarding the fascicle courses surrounding the tumor (κ = 0.78). Mean diffusivity of schwannomas (1.5 ±â€¯0.2 × 10-3 mm2/s) was significantly lower than in neurofibromas (1.8 ±â€¯0.2 × 10-3 mm2/s; P < 0.001). The Youden index showed an optimal cutoff at 1.7 × 10-3 mm2/s (sensitivity, 0.91; specificity, 0.78; J = 0.69). CONCLUSIONS: Preoperative diffusion tensor imaging allowed to accurately differentiate between schwannomas and neurofibromas and to describe their location in relation to the nerve fascicles for preoperative planning.

Schwannoma Presenting as a Scalp Mass: A Case Report with Magnetic Resonance Imaging Findings.

A schwannoma can develop anywhere along the course of nerves. However, a schwannoma presenting as a scalp nodule is rare. Here, we present a rare case of schwannoma on the scalp with a review of magnetic resonance imaging (MRI) findings, which was initially misdiagnosed as an epidermal cyst or vascular malformation despite various radiologic examinations. Recognition of characteristic MRI features of schwannomas, such as low signal margin, target, entering-and-exiting-nerve, and fascicular signs, may result in an accurate diagnosis and proper management of tumors. In this report, we summarized differential characteristics of a schwannoma with an epidermal cyst and a lipoma.

Neurofibromas of the oral and maxillofacial complex: A 48-year retrospective study.

Neurofibromas are benign neoplasms of the peripheral nerve sheath, characterized by the proliferation of Schwann cells, perineural cells and endoneural fibroblasts. Their occurrence in the oral and maxillofacial complex is uncommon. This study aimed to evaluate the clinical and histopathological characteristics of neurofibromas of the oral and maxillofacial complex excised at our institution over a 48-year period. Using light microscopy, two previously trained oral pathologists re-evaluated all hematoxylin and eosin slides. From a total of 15,375 cases diagnosed at a referred Oral Pathology Service, 24 cases were diagnosed as neurofibromas. Eighteen neurofibroma patients were female, with a mean age of 39.1 years. Three patients presenting neurofibromas exhibited neurofibromatosis type I. Clinically, most of the lesions presented as asymptomatic nodules, and the most frequent sites were the tongue (n = 6; 25.0%), gingiva (n = 6; 25.0%) and intraosseous maxillary bone region (n = 3; 12.5%). Histopathologically, the lesions were predominantly well delimited, exhibiting interlocking bundles of spindle-shaped cells that usually displayed wavy nuclei, associated with delicate collagen fibers. Thus, knowledge of their clinical and histopathological features by dentists and oral pathologists is essential for the correct diagnosis of these lesions.