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Plexiform variants of neurofibromas and schwannomas are rare and typically arise in superficial soft tissues in the head and neck region. The treatment of these tumors is challenging and no generally accepted guidelines exist for their optimal management. The purpose of this study was to review the management and longterm prognosis of head and neck plexiform neurofibromas and schwannomas at 2 tertiary care academic hospitals in Finland over a 31-year period. The pathology files were searched for plexiform neurofibromas and schwannomas between the years 1990 and 2020. The case notes were reviewed for full management details. Two plexiform schwannomas and 6 plexiform neurofibromas were identified. Five of the 6 plexiform neurofibromas were managed operatively. All patients with a surgically managed plexiform neurofibroma underwent multiple operations. Sclerotherapy abolished 1 patient's cutaneous plexiform neurofibromas. The management of plexiform neurofibromas and plexiform schwannomas remains challenging. Sclerotherapy may offer a promising management option for cutaneous plexiform neurofibromas.

Cancer predisposition syndromes (CPS) are generally heritable conditions that predispose individuals to develop cancer at a higher rate and younger age than their representative general population. They are a significant cause of cancer related morbidity and mortality in the pediatric population. Therefore, recognition of lesions that may be associated with a CPS and alerting the clinicians to its implications is a crucial task for a diagnostic pathologist. In this review we discuss benign pediatric head and neck lesions associated with CPS namely: odontogenic keratocyst, juvenile nasopharyngeal angiofibroma, ossifying fibroma of the jaw, paraganglioma, plexiform neurofibroma, plexiform schwannoma, mucosal neuroma, and nevus sebaceous syndrome; along with malignant tumors such as squamous cell carcinoma. Several head and neck melanocytic, endocrine, and central nervous system tumors can also be associated with CPS; they are beyond the scope of this article. Nasal chondromesenchymal hamartoma is discussed elsewhere in this issue.

Highlights • Plexiform schwannomas are exceedingly rare in paediatric populations. • This is a unique case located outside the spinal canal without a nerve of origin. • Preoperative planning is imperative for complete resection and cosmesis., Introduction and importance Schwannomas are benign, slow-growing nerve sheath tumors of neoplastic Schwann cells. They are the most common peripheral nerve tumors in adults and are typically discovered incidentally due to their asymptomatic presentation. Despite the fact that most schwannomas are unassociated with a syndrome, their etiology is thought to be related to alterations or loss of the neurofibromatosis type two tumor suppressor gene. Case presentation We present the case of a fifteen-year-old female who presented with a recurrent lower back/upper buttocks 9 cm mass with imaging suspicious for schwannoma. Needle biopsy revealed an S100 positive cellular schwannoma with patchy Ki-67. During surgical dissection down to the sacrum, no nerve of origin was identified. Clinical discussion Schwannomas have no pathognomonic findings on MRI and may occur at any location that Schwann cells are present; therefore, confirming a diagnosis relies on histopathology. Plexiform schwannomas are defined by a “network-like” intraneural growth pattern and are exceedingly rare in paediatric populations. A location distinct from the spinal canal is also very rare as schwannomas typically originate from the head and neck region. Conclusion Paediatric plexiform schwannomas have been rarely reported. Surgical planning relies on multiple factors such as tumor size, tumor location, pathologic features and symptomatic burden. The distinctive features of this case including an unknown nerve origin and a location outside the spinal canal provide a unique opportunity to discuss the diagnosis and management of paraspinal schwannomas and the impact on operative planning when a nerve of origin is not identified.

Plexiform schwannoma is a rare benign variant of Schwann cell tumor characterised by multinodular plexiform growth pattern. Usual location of this tumor includes trunk, head, neck and upper extremities but it may rarely be found in lower extremities. It generally affects young adults with no sex predilection. We report a case of 37 years old male who presented with gradually progressive swelling of right little finger of 28years duration that was diagnosed as giant cell tumor of tendon sheath clinically, radiologically and intraoperatively. Authors wish to discuss the case due to its clinical rarity and diagnostic difficulties due to many common histological mimickers at that site.

Plexiform schwannoma represents an unusual schwannoma variant, characterized by multinodular growth grossly and/or microscopically. A review of the English-language literature reveals only 28 previously reported cases involving the oral cavity, and herein we present 8 additional cases. Among these 36 patients, the average age at diagnosis was 28 years (range 5 to 62 years), with a female-to-male ratio of 1.4:1. The most frequently involved sites were the tongue (n = 13) and lip (n = 11). Lesion duration prior to presentation averaged 5.3 years (range, 6 weeks to 26 years). The average lesion size was 2.1 cm (range, 0.3 to 16 cm). The typical clinical presentation was a painless mass, although infrequent findings included pain/discomfort, paresthesia, difficulty chewing, and limited buccal mobility. All cases clinically appeared as a solitary mass or localized cluster of tumor nodules, with the exception of one patient who had neurofibromatosis 2 (NF2) and exhibited two distinct nodules on the tongue and buccal mucosa. In addition, extraoral neural neoplasms were evident in four patients, including three with NF2. Typical microscopic findings included multiple well-circumscribed tumor nodules, each surrounded by a perineurium-derived capsule with immunoreactivity for epithelial membrane antigen. The nodules contained characteristically bland and diffusely S-100-positive spindle cells arranged in Antoni A and B patterns; however, modest nuclear pleomorphism was evident in three cases. Most patients (n = 23) were treated by excision or enucleation and curettage, and three patients experienced recurrence. Unlike plexiform neurofibromas, plexiform schwannomas exhibit only a weak association with neurofibromatosis and have no known malignant potential.

Plexiform schwannoma (PS), a subtype of schwannoma, is a rare benign nerve sheath tumor characterized by a multinodular plexiform growth pattern. It is usually confined to the head and neck or skin. Pelvic PS is an extremely rare occurrence and signifies a challenge for the imaging diagnosis. In this work, we present a 42-year-old woman with pelvic PS, who was initially suspected of malignant tumor on 18F-FDG PET/MRI but confirmed as PS by postoperative pathology. We consider that this case would contribute to the literature and provide a further insight into diagnosing this kind of rare tumor.

Background Plexiform schwannoma is one of the least common variants of schwannoma, accounting for only 5% of all schwannoma cases. It generally occurs in the skin and subcutaneous tissues and is uncommon in deep soft tissue or viscera. We present an extremely rare case of plexiform schwannoma arising from the peripancreatic plexus. Case presentation A 29-year-old man presented with hyperglycemia detected during a medical checkup. He was diagnosed with type 1 diabetes based on the clinical findings and laboratory tests. During the diagnostic process for diabetes, a 2.5 cm mass was incidentally detected in the pancreas by abdominal ultrasound. Contrast-enhanced computed tomography revealed a mass that was gradually enhanced at the body and tail of the pancreas. Magnetic resonance imaging revealed low signal intensity of the mass on T1-weighted images and high signal intensity on T2-weighted and diffusion-weighted images. Magnetic resonance cholangiopancreatography showed no abnormal findings in the main pancreatic duct. Endoscopic ultrasonography (EUS) showed a lobulated, low-echoic mass with a clear boundary. EUS-guided fine needle biopsy was performed, and spindle-shaped cells that were diffusely immunopositive for S-100 and negative for c-kit and desmin were detected, resulting in a diagnosis of a neurogenic tumor arising from the pancreas or the peripancreatic nerve plexus. The patient underwent laparoscopic spleen-preserving distal pancreatectomy. Although the tumor was connected to the splenic plexus, the splenic artery could be divided along its adventitial plane. Macroscopic findings of the excised tumor consisted of multiple yellowish-white nodules, and its histopathological features were consistent with plexiform schwannoma. There was no pancreatic tissue on the dorsal surface of the tumor, which suggested that the tumor arose from the peripancreatic nerve plexus. Conclusions The findings documented herein can aid in the differential diagnosis of peripancreatic schwannoma and in planning appropriate treatment.

Schwannomas represent only 5% of all soft tissue tumors. As a variant of this tumor, the plexiform schwannoma is rare accounting for less than 5% of all schwannomas. Herein, we report a rare case of a 49-year-old athlete who suffered from a pain in the posterior aspect of the right leg one year before his presentation. Initially, a radiograph of his right leg showed no abnormality, and so, the emergency physician discharged him on analgesics and anti-inflammatory medications, and rest was advised. The persistent pain obliged the patient to consult our orthopedic department. On examination, we found a firm mass in the proximal medial aspect of his right leg. The neurovascular exam was normal. Sonography of the leg was not conclusive. Therefore, magnetic resonance imaging was performed, and a hemangioma or schwannoma was suspected. The patient underwent surgery in which the entire tumor mass was shelled out in one piece with no damage. The histopathological finding was concomitant with a plexiform schwannoma. Follow-up evaluation, sixteen months later, showed no evidence of recurrence, and the patient has regained his previous level of sportive activities. So, given the case described here, despite the rarity of the schwannoma, it should be taken into consideration as a possible diagnosis in such situation to promote early diagnosis and appropriate treatment.

Neurofibromatosis type II (NF2) is a tumor predisposition syndrome characterized by the development of distinctive nervous system lesions. NF2 results from loss-of-function alterations in the NF2 gene on chromosome 22, with resultant dysfunction of its protein product merlin. NF2 is most commonly associated with the development of bilateral vestibular schwannomas; however, patients also have a predisposition to development of other tumors including meningiomas, ependymomas, and peripheral, spinal, and cranial nerve schwannomas. Patients may also develop other characteristic manifestations such as ocular lesions, neuropathies, meningioangiomatosis, and glial hamartia. NF2 has a highly variable clinical course, with some patients exhibiting a severe phenotype and development of multiple tumors at an early age, while others may be nearly asymptomatic throughout their lifetime. Despite the high morbidity associated with NF2 in severe cases, management of NF2-associated lesions primarily consists of surgical resection and treatment of symptoms, and there are currently no FDA-approved systemic therapies that address the underlying biology of the syndrome. Refinements to the diagnostic criteria of NF2 have been proposed over time due to increasing understanding of clinical and molecular data. Large-population studies have demonstrated that some features such as the development of gliomas and neurofibromas, currently included as diagnostic criteria, may require further clarification and modification. Meanwhile, burgeoning insights into the molecular biology of NF2 have shed light on the etiology and highly variable severity of the disease and suggested numerous putative molecular targets for therapeutic intervention. Here, we review the clinicopathologic features of NF2, current understanding of the molecular biology of NF2, particularly with regard to central nervous system lesions, ongoing therapeutic studies, and avenues for further research.

Schwannomas are benign, encapsulated neurogenic tumors which present in diverse histological subtypes despite the limited variety of their cellular constituents. These include the cellular, ancient, cystic, epithelioid, melanotic, psammomatous, schwannoma with pseudoglandular elements, and plexiform varieties. The plexiform schwannoma (PS) represents 4.3% of all schwannomas. These lesions are commonly encountered in the head and neck region and are extremely rare in the penis. To the best of our knowledge only 34 cases of penile schwannomas have been reported and this is the 3rd case of plexiform penile schwannoma. A 39-year-old patient presented to our andrology outpatient clinic complaining for two painful penile nodules. The lesions were located on the dorsum of the penile shaft. His medical history was insignificant for penile trauma and sexual transmitted diseases. The masses measured 2x1 cm and 0.5x1 cm. After sonographic and magnetic resonance evaluation the patient was admitted to theatre and underwent topical resection of the lesions. Histopathology revealed plexiform schwannoma. Postoperatively, penile tenderness and hyperesthesia ensued which was managed with pregabalin administration and topical corticosteroids. Plexiform schwannomas are rare in the penile region. Surgical excision is inevitably the only way to diagnose and treat the lesions. They must be differentiated by a variety of malignant and benign clinical conditions. Topical excision suffices for oncological control and allows for acceptable functional outcomes.

BACKGROUND Schwannomas and neurofibromas are common benign neoplasms originating from the peripheral nerves. These neoplasms originating in the oral and para-oral tissues, especially involving the jaw, are extremely rare. Plexiform schwannoma is a unique variant in which the Schwann cells demonstrate a unique plexiform pattern. A literature search revealed only 2 case reports of plexiform schwannoma involving the jaws. CASE REPORT A 47-year-old male patient was referred for consultation by his dentist for evaluation and diagnosis of a radiolucency in the anterior mandible with no apparent odontogenic/clinical etiology. The patient complained of sensitivity in this region and occasional radiating pain. Clinical examination showed no signs of infection or inflammation. The patient denied any known medical disease or history of surgeries. Cone beam computed tomography examination revealed a large, well-defined, hypodense, partially corticated lesion in the anterior mandible with evidence of impingement of the facial cortex, resulting in a scooped-out defect. The radiologic differential interpretation included peripheral ameloblastoma and peripheral giant cell granuloma. An incisional biopsy was recommended to determine the nature of this entity. Microscopic examination revealed a multicircumscribed, lobular mass bounded by a thin fibrous connective tissue capsule. Each lobule was composed of streaming fascicles of spindle-shaped cells, some of which formed a palisading arrangement. Immunohistochemistry was positive for protein S-100 and epithelial membrane antigen, which confirmed the diagnosis of plexiform schwannoma. DISCUSSION/CONCLUSIONS This is an unusual case of a unique variant of schwannoma, in this case a plexiform type, which is an extremely rare neurogenic neoplasm. This atypical presentation and location of the lesion, which mimics other peripheral benign neoplasms, highlights the importance of a systematic workup with the aid of the appropriate diagnostic tools for ideal patient care. It demonstrates the important role of immunohistochemistry to confirm the nature of this entity.

Plexiform schwannoma (PS) is a benign tumour of the peripheral nerve sheath that is typically found in the skin. Fewer than 15 cases of visceral PS have been reported to date in both adults and children. We herein discuss a series of 3 patients (2 male and 1 female) with abdominal PS, aged 10-16 years (mean age, 12 years). All the patients had an acute presentation with abdominal pain, which was associated with rectal bleeding in 1 case and with walking difficulties in 1 case. Radiological investigations included abdominal magnetic resonance imaging (MRI) and computed tomography, along with neurofibromatosis screening (cerebral MRI and dermatological evaluation). Complete removal of the mass was possible in 2 of the patients (in 1 case by laparoscopically assisted surgery). Follow-up was uneventful. Abdominal PS is a rare occurrence. Due to its possible association with neurofibromatosis, the diagnosis of PS should prompt an investigation for other manifestations of this disorder.

Background Plexiform schwannoma (PS), variant of schwannoma, often involves multiple fascicles as plexiform neurofibroma, and is usually located superficially on the dermis and subcutaneous layers. Spinal PS is extremely rare, and there is insufficient information on its natural course and treatment strategy. We describe the clinical features and treatment of giant intradural PS at the lumbosacral spine. Case presentation A 66-year-old man presented with leg pain, paresthesia, and weakness for 2 years. Magnetic resonance imaging demonstrated a large mass lesion involving a continuous multi-lobulated bead-like mass and a cystic portion from L1 to S3. The lesion was iso-intense on T2-weighted images (WI), iso- to slightly low-intense on T1-WI, and heterogeneous enhancement on contrast-enhanced T1-WI. The large mass lesion had three portions, including a cystic mass at L1, continuous multi-lobulated bead-like mass with a cystic portion from L2 to S1, and multi-lobulated mass from S2 to S3, which were identified with severe adhesions with cauda equina on operative assessment. Grossly total extirpation was achieved at the lumbar spine, and remained three round shaped small masses at the lumbar area and a multi-lobulated round masses from S2 to S3 involving nerves related with motor function of the lower extremities and anal sphincter, respectively. Histological examination revealed multinodular or plexiform growth pattern composed of spindle-shaped tumor cells, which were diffusely and strongly positive for S100 protein with KI67 Conclusion Subtotal extirpation to minimize neural deficits and close observation can be considered an appropriate treatment strategy for a giant spinal PS considering its benign prognosis and histological features, with a high risk of neurological damage during surgery.

Les schwannomes du nerf sciatique sont des tumeurs rares. Elles se manifestent essentiellement par des névralgies sciatiques plutôt que par des déficits sensitivo-moteurs. Nous rapportons le cas d´une patiente de 30 ans présentant une douleur de la fesse droite depuis 1 an. La palpation a révélé un signe de Tinel positif. Une imagerie par résonnance magnétique (IRM) a été réalisée qui a objectivé une masse grossièrement arrondie, régulière de 2 cm de diamètre en contact intime avec le nerf grand sciatique. Une exérèse complète de la tumeur a été réalisée. Cette exérèse a permis la disparition de la douleur et l´examen anatomopathologique a conclu à un schwannome plexiforme.

Background: Plexiform schwannomas are usually sporadic. In hereditary diseases they are linked to benign and aggressive malignant tumors. Schwannomas of the hypoglossal nerve are very rare and mostly develop at the skull base without plexiform variant. Case presentation: In the floor of the mouth a salivary gland tumor was suspected on imaging of an 11-year-old girl. Intraoperatively the tumor was connected to the hypoglossal nerve. There were no postoperative functional deficits. Histology identified a plexiform schwannoma with collagen pseudorosettes. Molecular-genetic testing of genomic and tumor DNA could not identify a pathogenic variant in the NF2, SMARCB1, or LZTR1 genes. The patient is currently free of disease 74 months postoperatively. Conclusion: In case of a histological diagnosis of schwannoma, particularly in children, immunohistochemical examinations should be carried out and depending on these results human-genetic diagnosis is indicated.

Plexiform schwannoma is an extremely rare variant of schwannoma, accounting for approximately 5% of cases. Due to the rarity and lack of typical symptoms, signs and radiological images, a definite diagnosis of plexiform schwannoma may not be made by clinicians prior to biopsy. In the present study, we report the first case (to our knowledge) of perianal plexiform schwannoma arising from the overlapped skin of the ischioanal fossa, and we propose an intratumorally nonenhanced circumferential capsule dividing the tumour into multiple homogeneously enhanced nodules as a magnetic resonance imaging feature to aid in the differential diagnosis of plexiform schwannoma from ancient schwannoma, cavernous haemangioma, liposarcoma and plexiform neurofibroma.

Schwannoma is the most common type of benign tumor arising from the sheaths of the peripheral nerves. It occurs as a solitary tumor in most cases, but when it appears in multiple forms, it is necessary to differentiate it from plexiform schwannoma, schwannomatosis, neurofibroma and malignant peripheral nerve tumors. The authors experienced schwannomatosis in the tibial nerve without the features of neurofibromatosis type 2, so here we present a case report and literature review.

Unusual vulvar neoplasms comprise a small minority of general surgical pathology cases; however the four unusual vulvar tumours presented herein were diagnosed at our institution within the last few years, underscoring the importance of recognizing these entities. We have focused our discussion on mesenchymal lesions, but also included extramammary Paget disease. Our cases include: extramammary Paget disease, solitary fibrous tumour, plexiform schwannoma and epithelioid sarcoma, proximal-type. Pathogenesis, clinical presentation, morphology, differential diagnosis, ancillary studies, treatment and prognosis, will be discussed.

Plexiform schwannoma is a rare Schwann cell tumor that usually occurs in the head and neck. Here, we report a giant plexiform schwannoma (5.5 × 4.0 cm) in the right plantar aspect of the foot. This tumor presented from the dermis to the subcutaneous fat in the plantar aspect, forming a multiocular shape.

A common mimicker of Plexiform Neurofibroma (PN), Plexiform Schwannoma (PS) can occur sporadically and in weak association with NF2. It is important to differentiate between the two, as recurrence and malignant potential are common with PN requiring extensive surgery and rigorous follow-up. Though light microscopic features of PN and PS overlap especially in small biopsies, IHC with S-100 would help. S-100 immunostaining is diffuse and strong in PS while weak and patchy in PN. A rare case of cutaneous PS in the right index finger of a nine-year-old boy where S-100 immunostaining helped to confirm the diagnosis is hereby reported.

Plexiform schwannoma (PS) is an uncommon variant of schwannoma characterized by a multinodular (plexiform) growth pattern. It comprises up to 5 % of all schwannomas. The association between PS and neurofibromatosis type 1 or type 2 (NF1/NF2) is only rarely reported. Most cases of PS occur in the skin and subcutaneous soft tissue, with only a few reports of digestive tract involvement. We describe an 18-year-old male with NF2 who had bilateral vestibular schwannomas and multiple cutaneous PSs, and a 3-year history of abdominal pain. The patient ultimately underwent a distal gastrectomy for a partially obstructing submucosal antral mass, associated with an overlying ulcer. Histopathologic examination showed the mass to be a PS. The patient is alive and well, without symptoms, 12 months postoperatively. A review of the English language medical literature yielded only ten examples of PS arising in the digestive tract. Our patient is the first to be reported to have a gastric PS, and only the second patient to be reported with a digestive tract PS to have NF2, and the only patient reported to have both digestive tract and cutaneous PSs. Despite its rare occurrence with NF2, the finding of PS at any site should stimulate an examination for other manifestations of this disorder. Clinical Trial Registration: None.

Introduction: Peripheral nerve sheath tumors (PNSTs) are neuroectodermal in origin. Now these tumors are classified under World Health Organization (WHO) classification of tumors of soft tissue and bone 2013. Objective: To study the morphological spectrum of PNST and to study the secondary degenerative changes associated with it. Materials and Methods: This study was conducted from January 2010 to June 2015. The gross details of tumor and patient's demographic profiles were reviewed. The hematoxylin and eosin stained slides were reassessed and the lesions were categorized and classified as per the WHO 2013 classification. The tumors were also assessed for secondary degenerative changes. Results: Our study comprised 143 cases of PNST. Age of the patients ranged from 5 to 75 years. 21–30 years is the most common age of occurrence with head and neck being the most common site. The PNSTs observed in the present study were neurofibroma (NF) (61.5%), schwannoma (36%), malignant PNST (2%), and granular cell tumor (0.5%). Nearly 10% of NF fulfilled the criteria for neurofibromatosis 1 (NF1). Rare tumors such as plexiform schwannoma and granular cell tumor were also observed. Malignant tumors were larger in dimension than benign. Myxoid, cystic, and hyaline changes were commonly associated with benign tumors while necrosis, hemorrhage, and mitotic activity were seen with malignant tumors. Conclusion: This series highlights the pathological variants of PNST along with their morphological changes and NF1 association. It is essential to be familiar with all these variants of PNST for accurate diagnosis as they have varied biological behavior.

Schwannoma is rare peripheral nerve sheath tumor arising from Schwann cells. It is generally benign but may show malignant transformation. Perineal location of these tumors is very rare. We operated a 6-year-old boy with perineal mass, which turned out to be a schwannoma. We are presenting the description of the case and review of the relevant literature.

A 49-year-old woman with a long history of a subcutaneous mass on the dorsal side of her 4th finger of the right hand visited a dermatologist because of slight enlargement of the mass. Her past medical history was notable only for a mitral valvuloplasty performed 20 years earlier. Physical examination revealed a small, round, firm subcutaneous mass on the dorsal side of her proximal interphalangeal joint of the right 4th finger. The mass was immobile and nontender and its overlying skin was intact. An excisional biopsy was done for the patient and the specimen was sent for pathologic evaluation. On microscopic examination, the final diagnosis of plexiform schwannoma was made for the lesion. The aim of this publication is to report a rare case of plexiform schwannoma of the soft tissue and a literature review to provide a better understanding about its characteristics including epidemiologic factors and pathologic evaluation.

Plexiform schwannoma is a rare tumor in the lower extremity which grows slowly and is noninvasive. The tumor size is usually less than 2 cm. The main affected population of this disease is concentrated on the age group of 20 to 50 years old. In this study, we reported a rare case of 66-year-old male with a large soft tissue mass on his right foot with a tumor size larger than 7 cm. The ultrasound was performed and showed circumscribed hypoechoic image, indicating a suspected diagnosis of lipoma. The subsequent MRI showed a multilobulated heterogenous signal on T2WI and STIR sequence with mild enhancement, suggesting hemangiomas. Then the tumor of the patient was removed for pathological examination and the results confirmed the diagnosis of plexiform schwannoma. Patient recovered well and had no recurrence in 9 months after the surgery. CT, MRI, and ultrasound are useful to distinguish these rare tumors from other soft tissue lesions, in contrast, MRI has higher sensitivity and provides more accurate diagnostic information. This case report provides a deep understanding of plexiform schwannoma. In the diagnosis of large soft tissue tumors in the lower extremity of the elderly, attention should be paid to the differential diagnosis of plexiform schwannoma to improve the diagnosis level.

Background: Approximately 25–45% of schwannomas are typically slow-growing, encapsulated, and noninvasive tumors that occur in the head-and-neck region where they rarely involve the retropharyngeal space. Here, we report deep-seated benign plexiform schwannoma located in the retropharyngeal C2-C5 region excised utilizing the Smith-Robinson approach. Case Description: A 30-year-old male presented with dysphagia and impaired phonation attributed to an MR documented C2-C5 retropharyngeal schwannomas. On examination, the lesion was soft, deep seated, and extended more toward the right side of the neck. Utilizing a right-sided Smith-Robinson’s approach, it was successfully removed. The histopathology confirmed the diagnosis of a plexiform schwannoma. Conclusion: Retropharyngeal benign plexiform schwannomas are rare causes of dysphagia/impaired phonation in the cervical spine. MR studies best document the size and extent of these tumors which may be readily resected utilizing a Smith-Robinson approach.

The purpose of this study was to investigate the usage of an anatomical model to improve surgical planning of a complex schwannoma resection. As advancements in additive manufacturing continue to prosper, new applications of this valuable technology are being implemented in the medical field. One of the most recent applications has been in the development of patient-specific anatomical models for unique clinical education as well as for preoperative planning. In this case, a multidisciplinary team with expertise in research, three-dimensional printing, and medicine was formed to develop a three-dimensional printed model that could be used to help plan the reduction of a tumor from the cervical spine of a pediatric patient. Image segmentation and stereolithography creation were accomplished using Mimics and 3-matic, respectively. Models were developed on two different printer types to view different aspects of the region of interest. Reports from the operating surgeon indicated that the model was instrumental in the planning procedures of the operation and reducing operation time.

Schwannoma, a benign nerve sheath tumor, is quite rare and more so in jawbones. We report a rare case of a plexiform variant of mandibular schwannoma in a 12-year-old female with a swelling in the left mandible. Clinical features were suggestive of dentigerous cyst as a result of missing premolars and canine. Occlusal and panoramic radiography revealed an osteolytic lesion with scalloping margins, bicortical plate expansion, and agenesis of several teeth. Odontogenic keratocyst, central giant cell granuloma, odontogenic myxoma, and ameloblastic fibroma were given as radiological differential diagnoses. Histopathological examination revealed features of plexiform schwannoma which was given as the final diagnosis. The lesion was treated with surgical excision. Although odontogenic cysts/tumors are often thought of in differential diagnosis whenever well-defined radiolucencies in the jaw are encountered, it is prudent to include schwannoma. This exceptional case adds light to the fact that schwannoma should not be overlooked though it is a rare possibility and must be included in differential diagnosis of odontogenic cysts/tumors.

Plexiform schwannoma is a rare variant of schwannomas and usually presents with chronic symptoms. We herein report a case of cervical nerve plexiform schwannoma that presented with unusually sudden severe left radiculopathy of the eighth cervical nerve after physical exercise. Coronal short-tau inversion recovery (STIR) magnetic resonance imaging (MRI) revealed a multinodular tumor along the eighth cervical nerve. The tumor was partially resected. A pathological analysis revealed that the tumor was a schwannoma, and we diagnosed the case as a plexiform schwannoma. The unusual sudden-onset presentation in this case was considered to be caused by the unusual localization of the tumor involving the nerve root and mechanical stress due to physical exercise.

Introduction. Plexiform schwannoma is a rare variant of schwannoma that accounts for only 5% of all schwannomas. Herein, we present a rare case of plexiform schwannoma of the tongue in a pediatric patient with neurofibromatosis type 2 (NF2).Case Presentation. A 13-year-old female presented with a growing left-sided tongue mass. The patient has a past medical history of NF2. The tongue mass was excised and histopathological examination revealed a spindle cell tumor with multinodular growth pattern, with Verocay bodies' formation. Tumor cells were strongly positive for S-100 protein and negative for smooth muscle actin (SMA), and EMA highlighted perineural fibroblasts surrounding tumor nodules. These findings were diagnostic of plexiform schwannoma.Conclusion. Plexiform schwannoma of the tongue is an extremely rare tumor seen in patients with NF2. Clinical examination and histopathological evaluation are important for diagnosis of plexiform schwannoma.

Rare epithelial structures in benign nerve sheath tumors are almost always glandular in appearance. We describe a case of intraoral plexiform schwannoma with concurrent squamous epithelial hyperplasia. The lesion occurred as a pigmented nodule on the gingiva of a 35-year-old woman with no systemic involvement. Histologically, unencapsulated, plexiform fascicular proliferations of schwann cells could be traced from the submucosa to the lamina propria, finally making direct contact with heavily pigmented, elongated rete ridges of the overlying epithelium. Also noted was a schwannian network centered on clustered odontogenic epithelial rests of mature squamous-type, the number and size of which had markedly increased. Impressive immunoprofiles of periepithelial neural microfascicles included the complete absence of axon and perineurium and the unexpected presence of endoneurial fibroblasts. The repertoire of epithelial changes was in a confined area with no extension beyond, supporting hyperplasia induction by an underlying/surrounding schwannoma.

AIMS: To treat and manage a swelling on the lower lip which was insidious in onset and as gradually progressive on a 18 year old female. This has been a rare case and could be the first one in India as it was located on the lower lip with very few cases reported in the literature. MATERIALS AND METHODS : An 18 year old female was referred to our Out Patients Department (OPD). The patient was apparently normal 10 years back when she developed a swelling of the lower lip which was insidious in on - set gradually progressive. Initially, it was of the size of 1 x1 cm and gradually increased to 3x3cms. OBSERVATION : It was noted that in the Antoni A area typical verocay bodies composed of palisading nuclei and surrounding spaces filled with eosinophilic filaments. No necrosis was noted and there were no atypical mi totic figures . In the Antoni B region a closely textured matrix with areas of edema, myxomatous changes cystic degeneration and dilated vessels were noted, Fig. 4a, b & c. On the basis of these histopathologic findings a diagnosis of Plexiform Schwannoma w as inferred. On the basis of histopathologic findings and immunohistochemical profiles, a diagnosis of Plexiform Schwannoma was confirmed. CONCLUSION: The excised mass revealed benign microscopic features and confirmed complete removal. Malignant transform ation of a benign Plexiform Schwannoma which has been controversial by some authors was not considered. Surgical removal of the mass is considered to be the best course of treatment.

An 18-year-old female presented with a swelling on the lower lip, which was insidious in onset and gradually progressive. The mass was completely excised under local anaesthesia. Complete histopathologic and immunohistochemical studies were conducted. The Antoni A areas were found along with typical verocay bodies composed of palisading nuclei and surrounding spaces filled with eosinophilic filaments. No necrosis was noted and there were no atypical mitotic figures. In the Antoni B region, a closely textured matrix with areas of edema, myxomatous changes, cystic degeneration and dilated vessels were noted. On the basis of the histopathologic and immunohistochemical staining with S-100 protein, a diagnosis of plexiform schwannoma was made and has been reported in this study. The post-operative view confirmed complete recovery after 6 weeks of surgery. This is a rare case with the tumour located in the lower lip, as very few cases have been reported in literature and it may be the first one reported from India.

Multiple schwannomatosis, is defined as two or more, pathologically proven schwannomas, without radiographic evidence of vestibular nerve tumor, below 18 years, or absence of VIII nerve dysfunction beyond 30 years with absence of stigmata of neurofibromatosis 2 (NF2). The plexiform schwannoma (PS) is a rare tumor. The gross appearance is an important diagnostic criterion for diagnosis of PSs. It is associated with NF2, which was ruled out in this case. Here we present a 50 year female patient with two nonintradermal schwannomas, in the supraclavicular and infraauricular deep soft tissues. One was plexiform, diagnosed on cytology and confirmed by histopathology. She also had multiple pulmonary and pleural lesions. Fine needle aspiration cytology smears from both supraclavicular and infraauricular lesions as well as the lung lesion sampled, showed spindle cells in a myxoid background, having wavy nuclei with pointed ends. Verocay body - like palisading of nuclei was noted.

Plexiform schwannomas are peripheral nerve sheath tumours rarely found in the spine. We present a case of a 65-year-old male with a spinal plexiform schwannoma in order to add to the general fund of knowledge regarding the natural history, diagnosis and surgical management of this extremely rare clinical entity.

Plexiform schwannoma is a rare subtype of schwannoma with no case reported in the breast to the best of our knowledge. We report a case of intramammary plexiform schwannoma in a 20-year-old female which was diagnosed as Phyllodes tumour on cytology. Marginal resection is curative. This diagnosis show be kept in mind when reporting on Fine Needle Aspirates of stromal lesions of breast.

We report the case of a patient who noticed muscle weakness in his left arm 5 years earlier. On examination, a biloculate mass was observed in the left supraclavicular area, and Tinel's sign caused paresthesia in his left arm. Magnetic resonance imaging showed a continuous, multinodular, plexiform tumor from the left C5 to C7 nerve root along the course of the brachial plexus to the left brachia. Tumor excision was attempted. The median and musculocutaneous nerves were extremely enlarged by the tumor, which was approximately 40 cm in length, and showed no response to electric stimulation. We resected a part of the musculocutaneous nerve for biopsy and performed latissimus dorsi muscle transposition in order to repair elbow flexion. Morphologically, the tumor consisted of typical Antoni A areas, and immunohistochemistry revealed a Schwann cell origin of the tumor cells moreover, there was no sign of axon differentiation in the tumor. Therefore, the final diagnosis of plexiform Schwannoma was confirmed.

Plexiform schwannoma is a soft tissue tumor that rarely presents in the lower extremity. We have reported on 2 cases of plexiform schwannomas that occurred in the foot and ankle. Owing to the relative obscurity of this condition in the lower extremity, we have also provided an overview of plexiform schwannomas and discussed the differences between this and other suspicious nodular soft tissue masses. The first patient was a 38-year-old female, who had a soft tissue mass located on the lateral aspect of her right foot that became symptomatic. The second patient was an 11-year-old male, who had a symptomatic soft tissue mass on the plantar aspect of his right foot. Both patients underwent surgical excision of the tumor.

Plexiform schwannoma is a benign tumour arising from the sheath of myelinated nerve fibres that may occur in any part of the body. It is very rare in the head and neck region and poses diagnostic challenges. Here we present two unusual cases. The first is about a fifteen-year-old boy with a large plexiform schwannoma in the right retro maxillary region, extending up to but not invading the orbit. Initial cytology reported it as a pleomorphic adenoma, but histological findings after excision confirmed it to be a benign plexiform schwannoma. A zygomatic osteotomy was required to excise the tumour in its entirety. The second reported case is about solitary lesion on the tongue of a 46-year-old Chinese man, clinically mimicking a mucocoele. This case report highlights the diagnostic challenges posed by plexiform schwannoma, and the role of imaging and cytopathology, as well as the importance of definitive histopathological analysis. It also describes the surgical management of these lesions, and provides a review of the literature, in particular of cases occurring in the head and neck region.

Plexiform schwannoma represents an unusual schwannoma variant, characterized by multinodular growth grossly and/or microscopically. A review of the English language literature reveals only 30 previously reported cases involving the oral/pharyngeal region, and herein we present 4 additional cases. Among these 34 cases, the average age at diagnosis was 27 years (range 5 to 58 years), with a female-to-male ratio of 1.3:1. The most frequently involved sites were the lips (n=11) and tongue (n=11). Lesion duration prior to presentation was reported in 15 cases and ranged from 6 weeks to 26 years. The average lesion size was 2.1 cm (range 0.4 to 8.5 cm). Three tumors were described as “large” or “giant,” including one extending from the sublingual region to the mediastinum. The typical clinical presentation was a solitary/localized, painless, and slowly enlarging swelling. However, 5 patients exhibited other clinical findings (e.g., pain/discomfort, sore throat, dysphagia, dyspnea). Three cases arose in association with neurofibromatosis 2 (NF2). Other neural tumor types (e.g., conventional schwannoma, meningioma) and/or >1 plexiform schwannoma were found in 5 patients (3 with NF2 and 2 who did not fulfill diagnostic criteria for NF2). Microscopic examination typically showed a proliferation of multiple well-circumscribed tumor nodules, each surrounded by a thin capsule. Antoni A and B patterns were evident in varying proportions. Infrequent histopathologic findings included ancient change (n=1) and induction of adjacent surface epithelium/odontogenic epithelial rests (n=1). Immunohistochemical findings included reactivity for S-100 protein among the tumor cells (15/15 cases), reactivity for EMA among capsular perineural cells (3/4 cases), and no reactivity for NFP among the tumor cells (6/6 cases). Most patients (n=22) were treated by excision or enucleation. Among the 14 cases for which follow-up information was provided, 3 recurred. Unlike plexiform neurofibromas, plexiform schwannomas exhibit only a weak association with neurofibromatosis and have no known malignant potential.

Schwannomas are benign peripheral nerve sheath tumors originating from the Schwann cells. Most schwannomas in the head and neck region are solitary; however, multiple schwannomas affecting one or more nerves suggest a possible association with neurofibromatosis type 2 and schwannomatosis. Plexiform schwannoma is a rare variant of conventional schwannoma that is characterized by intraneural multinodular growth. This grow pattern has also been observed with other neural tumors which may make diagnosis more difficult. Herein, we report the case of a 28-year-old woman who presented a solitary plexiform schwannoma of great palatine nerve. In the present case, we focused on immunohistochemical analysis in daily practice for the differential diagnosis of schwannomas and their mainly morphological mimics, especially with plexiform neurofibroma, granular cell tumor and malignant peripheral nerve sheath tumors. We also discussed on SMARBC1/IN1 marker usefulness in combination with brain magnetic resonance imaging for the distinction of solitary schwannoma from neurofibromatosis type 2 or schwannomatosis.

Plexiform schwannoma is an uncommon benign neoplasm of the neural sheath characterized grossly and microscopically by multinodular growth. It is typically presented as a mobile, solitary, smooth-surfaced, and nontender mass. Histologically, schwannomas are classified into the following seven types: classical (Verocay), plexiform, cellular, cranial nerve, melanotic, degenerated (ancient), and granular cell schwannomas. In spite of the fact that plexiform schwannoma commonly occurs in the head-and-neck region, the involvement of the lip is considered to be extremely rare. Herein, we present the case of a 16-year-old boy with the schwannoma on the lower lip excised without any recurrence at 9 months after surgery.

Macrodactyly is a rare anomaly. Little is understood about the etiology and underlying mechanisms. To our knowledge, macrodactyly has not previously been associated with neurofibromatosis type 2. We present a case of macrodactyly of the small finger associated with a digital nerve plexiform schwannoma in a patient with neurofibromatosis type 2.

Acquired clitoral enlargement is a rare condition resulting from a variety of etiologies, including tumors and excess androgens. Few cases of nonmalignant schwannoma, a benign tumor of the peripheral nerve sheath, have been reported in the literature as causes of clitoral enlargement in patients without known neurofibromatosis. These painless, slow-growing tumors rarely recur once excised. We present the initial investigation of a patient with a large clitoral schwannoma and subsequent treatment with partial vulvectomy. The workup, including advanced pelvic imaging for diagnosis and surgical planning, as well as removal of the clitoral tumor with preservation of functional tissue and restoration of normal vulvar anatomy despite a large excision, is demonstrated.