Exuberant Plexiform Neurofibroma

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Plexiform neurofibromatosis of the lower back: A rare case report

INTRODUCTION

Plexiform neurofibromatosis is a relatively rare manifestation of Type 1 neurofibromatosis (NF-1). This condition leads to gross disfiguration along with functional disability. We are presenting a case of 49 year male with Plexiform neurofibromatosis of lower back. The aim of this rare case report is also to discuss the management difficulties encountered.

PRESENTATION OF CASE

A 49 year male presented to us with gradually increasing swelling over the lower back which was present since his 10 years of age. He had already undergone debulking surgery for the same swelling 10 years back. For the last 2 years the swelling had increased in significant amount. He gave history of similar swellings in his father and grandfather. Proper examination revealed multiple café au lait macules, giant plexiform neurofibroma over lower back and multiple nodular swellings all over the body (neuroma). Biopsy report from previous surgery showed neurofibroma. He underwent debulking surgery. The procedure went for 12 h continuous. Intraoperatively, the mass was highly vascular and excessive bleeding was encountered. About 3 L of blood loss was there and patient received 12 units of blood products.

DISCUSSION

Plexiform neurofibromas are uncommon and may occur in around 30 % patients with NF-1. The genetic defect lies in chromosome 17 that encodes a protein neurofibromin. It causes disfiguration and severe distress to patients. Debulking surgery is one of the treatments to decrease the difficulties occurred from the mass. The aim of this report is to discuss the difficulties occurred in surgical intervention of this rare condition like excessive blood loss.

CONCLUSION

Although timely intervention could limit the disfigurement and morbidity associated with large lesion, due to unpredictable natural course and growth pattern, it is difficult to decide best time to intervene surgically. Registration of such rare case facilitates patient monitoring and development of appropriate treatment protocols.

Hybrid Ameloblastoma Arising from a Treated Odontogenic Keratocyst of the Mandible: A Case Report With Literature Review

Odontogenic Keratocyst (OKC) is an odontogenic cyst of developmental origin arising from remnants of the dental lamina. Malignant or benign transformations though rare have been noticed from their epithelium. Ameloblastomatous transformation from an OKC is extremely rare with such lesions being referred to as combined/"hybrid" odontogenic lesions. In this article, we present an intriguing case of a 60-year-old male who was operated on for OKC of the anterior mandible 3 years before, who came back with a complaint of swelling over the same site. Incisional biopsy revealed the acanthomatous type of ameloblastoma for which segmental resection with immediate reconstruction using recon plate was done. Excision biopsy revealed a plexiform variant as well, thus exhibiting a hybrid pattern. Surgeons should be aware of this hybrid presentation of ameloblastoma arising from the epithelium of OKC as the acanthomatous subtype is known for its notorious genetic behavior leading to recurrence and aggressive nature of this tumor.

Plexiform fibromyxoma: Review of rare mesenchymal gastric neoplasm and its differential diagnosis

Plexiform fibromyxoma (PF) is a very rare mesenchymal neoplasm of the stomach that was first described in 2007 and was officially recognized as a subtype of gastric mesenchymal neoplasm by World Health Organization (WHO) in 2010. Histologically, PF is characterized by a plexiform growth of bland spindle to ovoid cells embedded in a myxoid stroma that is rich in small vessels. The lesion is usually paucicellular. While mucosal and vascular invasion have been documented, no metastasis or malignant transformation has been reported. Its pathogenesis is largely unknown and defining molecular alterations are not currently available. There are other mesenchymal tumors arising in the gastrointestinal tract that need to be differentiated from PF given their differing biologic behaviors and malignant potential. Histologic mimics with spindle cells include gastrointestinal stromal tumor, smooth muscle tumor, and nerve sheath tumor. Histologic mimics with myxoid stroma include myxoma and aggressive angiomyxoma. Molecular alterations that have been described in a subset of PF may be seen in gastroblastoma and malignant epithelioid tumor with glioma-associated oncogene homologue 1 (GLI1) rearrangement. The recent increase in publications on PF reflects growing recognition of this entity with expansion of clinical and pathologic findings in these cases. Herein we provide a review of PF in comparison to other mesenchymal tumors with histologic and molecular resemblance to raise the awareness of this enigmatic neoplasm. Also, we highlight the challenges pathologists face when the sample is small, or such rare entity is encountered intraoperatively.

Paraspinal plexiform schwannoma of unknown nerve origin: A case report

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Plexiform schwannomas are exceedingly rare in paediatric populations.

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This is a unique case located outside the spinal canal without a nerve of origin.

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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.

Metastasizing Ameloblastoma: A 10 Year Clinicopathological Review with an Insight Into Pathogenesis

Ameloblastoma, a benign but locally aggressive odontogenic tumor, often demonstrates metastasis despite benign histological features and this variant is termed as metastasizing ameloblastoma (METAM). It was classified under the malignant category in the 2005 WHO but has been re-classified under benign epithelial odontogenic tumors in the latest 2017 WHO classification. The present review aimed at gathering the available data on METAM to update the current cognizance about the pathology. Comprehensive search of the databases (viz., PubMed, Medline, SCOPUS, Web of Science, EMBASE and Google Scholar) was done for published articles on METAM following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A total of 42 cases were extracted. The mean age of occurrence was 42.71 ± 15.87 years. A slight male predilection was noted. Mandibular cases showed more metastasis than maxillary cases. Follicular ameloblastoma was most frequently encountered at secondary site followed by plexiform type. Lungs were the most commonly affected secondary sites. METAM is a rare odontogenic tumor and the diagnosis is usually made in retrospect. Inadequate treatment may result in multiple recurrences and metastasis in rare instances. Metastasis in ameloblastoma appears to be multi-factorial in nature and needs further investigation in untapped territory like exploration of quantum effects at cellular and molecular levels.

Spinal manifestations of Neurofibromatosis type 1

BACKGROUND

Neurofibromatosis type 1 (NF1) patients may present a wide spectrum of spinal pathologies. Osseous changes may lead to severe deformities with significant implications on growth and quality of life. Neurogenic tumors and soft tissue abnormalities may cause neuropathic pain and dysfunction ranging from minor paresthesias to profound motor and sensory deficits. Advanced imaging such as whole-body MRI, and volumetric tumor burden assessment have an evolving role in the evaluation and follow-up of patients with high spinal tumor load. Novel biological agents that target the hyperactivated ras pathway are currently under investigation and are reshaping current and future treatment paradigms. Surgical interventions for benign and malignant tumors, as well as deformity correction remain pivotal in treatment frameworks and require careful assessment by a dedicated multidisciplinary team.

PURPOSE

In this manuscript we review the various spinal manifestations of NF1 patients, indication for surgical intervention and oncological treatments.

Frequency of Plexiform Fibromyxoma relative to gastrointestinal stromal tumor: A single center study. Ann Diagn Pathol. 2020;48:151568. [PMID: 32717659 DOI: 10.1016/j.anndiagpath.2020.151568]

Plexiform Fibromyxoma (PF) is an exceedingly rare mesenchymal tumor of the gastric antrum that was first described in 2007. PF is a close mimic of gastrointestinal stromal tumor (GIST) clinically and histopathologically, but the frequency of PF relative to GIST is unknown. Moreover, although likely benign, long-term follow-up of PF is limited due to its recent description and rarity. PF has not been reported in distal jejunum. 118 primary GISTs that were surgically resected at our center (2000-2019) were retrieved. The patients' age, gender, clinical presentation, tumor location, size and number, and the presence or absence of metastasis, were documented. Risk of progressive disease was assessed according to the published GIST risk stratification model. Two unique cases of PF were compared. One gastric PF has been followed-up for 8 years, and the other occurred in the distal jejunum. In the latter, the PF diagnosis was rendered after the case was re-reviewed for the study. Clinical presentation resembled GIST in both PF cases. 14% of GISTs showed high risk features or were clinically malignant, whereas the PF patient with 8-year follow-up was free of disease. Based on this study, PF may be under-recognized, with 1 to 2% (1.7%) of GIST-like tumors possibly representing PF. PF may involve variable segments of intestine similar to GIST. Given the remarkable clinical and histopathologic overlap with GIST but differing outcomes, awareness and cognizance of this rare entity, plexiform fibromyxoma, is required for proper patient care.

Plexogenic pulmonary hypertension associated with POEMS syndrome

Pulmonary hypertension is one of the well-known clinical manifestations of polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes (POEMS) syndrome, occurring in approximately 25–30% of the affected individuals. However, the histopathologic spectrum of pulmonary hypertension associated with POEMS syndrome has not been fully documented in the literature. Herein, we report an autopsy case of POEMS syndrome in a patient whose lung tissues showed histopathology indistinguishable from that of idiopathic pulmonary arterial hypertension with abundant plexiform lesions in the small pulmonary arteries.

Ultrasound assessment of peripheral nerve pathology in neurofibromatosis type 1 and 2

OBJECTIVE

The neurofibromatoses (NF) type 1 and 2 are hereditary tumor predisposition syndromes caused by germline mutations in the NF1 and NF2 tumor suppressor genes. In NF1 and 2, peripheral nerve tumors occur regularly. For further characterizing nerve ultrasound was performed in patients with NF1 and 2.

METHODS

Patients with established diagnosis of NF1 (n=27) and NF2 (n=10) were included. Ultrasound of peripheral nerves and cervical roots was performed during routine follow-up visits. Healthy volunteers were studied for comparison.

RESULTS

In patients with NF1, median cross-sectional area (CSA) of most nerves was significantly increased compared to controls and to NF2 due to generalized plexiform tumors, which arose out of multiple fascicles in 23 of 27 patients (85%). These were often accompanied by cutaneous or subcutaneous neurofibromas. In NF2, the overall aspect of peripheral nerves consisted of localized schwannomas (80%) and, apart from that, normal nerve segments.

CONCLUSION

Nerve ultrasound is able to visualize different nerve pathologies in NF1 and NF2. It is a precise and inexpensive screening method for peripheral nerve manifestation in neurofibromatosis and should be considered as the first choice screening imaging modality for all peripheral nerves within reach of non-invasive ultrasound techniques.

SIGNIFICANCE

Ultrasound patterns of peripheral nerve pathologies are described for the first time in a large cohort of patients with NF1 and NF2. It is a suitable screening tool and enables targeted MRI analysis.

Analysis of Prevalence and Clinical Features of Ameloblastoma and its Histopathological Subtypes in Southeast Myanmar and Lower Northern Thailand Populations: A 13-Year Retrospective Study

INTRODUCTION

Prevalence of ameloblastomas has been established worldwide but collective data of ameloblastoma in Southeast Asian countries has not been well analyzed.

AIM

Aim of this study was to report analysis and comparison of the prevalence and demographic data of clinical features of ameloblastoma and its histopathological variants in Southeast Myanmar and lower Northern Thailand populations.

MATERIALS AND METHODS

A retrospective study on ameloblastoma was performed based on the availability of oral biopsy specimens in Faculty of Dentistry, Naresuan University, Phitsanulok, Thailand, between January 2002 and August 2015. The collected data were subjected to descriptive statistical analyses with the SPSS version 17.0 statistical software package (SPSS Inc., Chicago, USA). Pearson's chi square (χ2) test and t-test were employed. The critical level of significance was set at p<0.05.

RESULTS

Total of 616 cases were reviewed, 30 cases (5%) were diagnosed as ameloblastoma with male:female ratio of 1.14:1. The mean age of the patients was 31.3±15.6 years. The predominance anatomical distribution was observed in the mandible (86.7%). Posterior body-ramus-angle region was the most common site. Almost all cases were asyptomatic and most common clinical manifestation was swelling of affected region. Multilocular radiolucency was observed in 70% of cases, whereas 30% were unilocular. Three subtypes of ameloblastomas were diagnosed: unicystic ameloblastoma (20%), conventional solid/multicystic ameloblastoma (70%), and desmoplastic ameloblastoma (10%). The most common histologic pattern was the plexiform type (57.2%) followed by follicular type (23.8%).

CONCLUSION

Prevalence of ameloblastoma in Southeast Myanmar and lower Northern Thailand populations correspond with data from other geographic areas of Thailand and other Asian countries. However, some demographic and histopathological profiles are different, with plexiform ameloblastoma being the most common subtype in this study.

A combined one-stage surgical approach of orbital tumor debulking, lid reconstruction, and ptosis repair in children with orbitotemporal neurofibromatosis

BACKGROUND AND AIM

To describe a series of children with neurofibromatosis type 1 (NF1) and a plexiform neurofibroma of the orbit with ptosis who underwent a combined one-stage surgery for tumor debulking, lid reconstruction, and ptosis repair.

METHODS

A retrospective review of 6 cases of combined one-step surgeries for orbital plexiform neurofibroma with ptosis.

RESULTS

The study included 6 children (4 boys, mean age 3.4 years). Follow-up time was at least 9 months. All children had unilateral orbitofacial plexiform. All children underwent a combined one-stage surgery performed by a single surgeon for tumor debulking, lid reconstruction, and ptosis repair. There was significant improvement in upper lid height and lid contour postoperatively in all the patients. One patient had early recurrence and underwent another two surgeries in the following years.

CONCLUSION

A combined surgical approach for orbital involvement in NF1 results in favorable immediate results, though late recurrence may require additional surgical interventions in the future.

Haversian microstructure in bovine femoral cortices: An adaptation for improved compressive strength

Microstructural variations in bovine femoral cortices and its possible implications for the bone's mechanical behavior are characterized for a mature and a young bovine femur. Histological examination at several locations shows the presence of Haversian systems to be largely confined to the posterior region of any cross-section. Haversian bone is shown to have higher compressive strength than the non-Haversian primary bone present in the corresponding anterior regions. The anatomical variation in the compressive strength along diaphysis is found to correlate strongly with the Haversian density. Based on the differences in the failure surfaces observed from compressive failure, it is argued that the presence of Haversian systems plays a role in deflection of crack path, leading to non-prismatic failure surfaces. As biomaterials, such as bone cement and implants, closely interact with bone material, the structure-property relation established here can provide a basis for better design of future biomaterials.

Plexiform Schwannoma of Lumbar Region

Plexiform schwannoma is an unusual peripheral nerve sheath tumor. It can mimic plexiform neurofibroma. A five-year-old girl presented with painful swelling in left lumbar region. Radiologic investigations showed a multinodular tumor in the subcutaneous plane of lumbosacral region. A complete excision and histopathologic examination revealed a plexiform tumor composed of hypocellular and hypercellular areas with verocay bodies. The tumor cells showed strong positivity for S-100 protein, rendering a final diagnosis of plexiform schwannoma. The child has been free of recurrence in 12-month follow-up.

Plexiform unicystic ameloblastoma: a case report and data analysis in the Indian population

Unicystic ameloblastoma (UA) among the different types of ameloblastomas is least encountered. The reason for lack of perception is paucity of case reports published in the literature. The UA, first described by Robinson and Martinez in 1977, is relatively a rare type of ameloblastoma accounting for about 10-15 % of all ameloblastomas. The term, plexiform UA, refers to a pattern of one or more nodules of ameloblasts like cells projecting from the cystic lining into the lumen of the cyst. Here we present a case of swelling in the anterior mandible of a 25 year old male which on histological examination revealed plexiform UA, which was later treated by complete surgical excision. A tabular data analysis of the previous UAs occurring in the Indian population according to the cases reported by Pubmed has also been included.

Solitary plexiform neurofibroma of the gingiva: unique presentation in the oral cavity

Neurofibromas are benign tumours originating from the nerve sheath. Amongst the histological variants, plexiform types are considered exclusive. These are poorly circumscribed, locally invasive and may exhibit sarcomatous potential. Plexiform neurofibromas are key features of Neurofibromatosis - 1 and their solitary intra-oral presentation is uncommon. The following case report describes a unique case of an isolated solitary plexiform neurofibroma of the maxillary anterior gingival region in a middle aged female patient.

Plexiform neurofibroma in the submandibular gland along with small diffuse neurofibroma in the floor of the mouth but without neurofibromatosis-1: a rare case report

Plexiform neurofibroma is more commonly seen in the orbit, neck, back, and inguinal region. It is extremely rare in the submandibular gland. These lesions rarely transform into malignancy but are locally infiltrative and can lead to haemorrhage. Therefore, plexiform neurofibroma should always be considered during differential diagnosis while excising a submandibular gland mass. We present here a case of plexiform neurofibroma in the submandibular gland and diffuse neurofibroma in the floor of the mouth in a 27-year-old female, not associated with neurofibromatosis-1.

Plexiform angiomyxoid myofibroblastic tumor of the stomach: report of two cases and review of the literature

Plexiform angiomyxoid myofibroblastic tumor (PAMT) of the stomach is a recently recognized entity. Because of its rarity, only 22 cases have been reported in the English-language literature and most of these are single case reports. We report two cases of gastric PAMT. The tumor cells were bland and plexiform arranged in a myxoid stroma, which was positive for alcian blue. Immunohistochemically, the tumor cells were positive for smooth muscle actin, but negative for c-kit, CD34, desmin, S-100 protein, epithelial membrane antigen, neurofilament, and protein kinase C-theta. Mutation analyses for exon 9, 11, 13, and 17 of KIT genes and 12, 14, and 18 of the platelet-derived growth factor receptor alpha (PDGFRA) genes were performed and the tumors were wild-type for mutation.

Plexiform ameloblastoma

The ameloblastoma is a benign but aggressive neoplasm of odontogenic origin. However, no enamel or hard tissue is formed by the tumor cells. Ameloblastomas are infamous for their invasive growth and their tendency to recur. Robinson (1937) as a benign tumor that is ‘usually unicentric, nonfunctional, intermittent in growth, anatomically benign and clinically persistent.’ They may occur at any age, even though nearly half of the tumors do occur between the ages of 20 and 40 years. This is the most common neoplasm affecting the jaws, yet only accounts for 1% of all tumors of the maxilla and mandible and 11% of all odontogenic tumors.

This report presents a case of ameloblastoma involving entire ramus and part of body of mandible with resorption of the mesial and distal root apices of second molar and distal root of mandibular first molar. The lesion extending till the base of mandible surrounding the crown of the unerupted third molar resembling the dentigerous cyst. This was surgically resected followed by harvesting the contralateral sixth costochondral rib graft.

How to cite this article: Celur S, Babu KS. Plexiform Ameloblastoma. Int J Clin Pediatr Dent 2012;5(1):78-83.

Plexiform angiomyxoid myofibroblastic tumor of the stomach: a case report

Plexiform angiomyxoid myofibroblastic tumor (PAMT) is a recently described mesenchymal tumor of the stomach. We report the first case of PAMT in Korea. A 52-yr-old man underwent esophagogastroduodenoscopy due to dyspepsia for 2 yr. There was a submucosal mass with small mucosal ulceration in the gastric antrum. The tumor measured 3.5 × 2.3 cm in size and showed multinodular plexiform growth pattern of bland-looking spindle cells separated by an abundant myxoid or fibromyxoid matrix rich in small thin-walled blood vessels. The tumor cells were negative for CD117 (c-KIT), CD34 and S-100 protein, but diffusely positive for smooth muscle actin consistent with predominant myofibroblastic differentiation. The patient is doing well without recurrence or metastasis for 5 months after surgery. Although there have been limited follow-up data, PAMT is regarded as a benign gastric neoplasm with histological and immunohistochemical characteristics distinguished from gastrointestinal stromal tumor and other mesenchymal tumors of the stomach.

Cutaneous plexiform schwannomas in a patient with neurofibromatosis type 2

Plexiform schwannoma is a rare benign neoplasm of the neural sheath characterized by a multinodular plexiform growth pattern. The tumor usually occurs as an isolated finding, although rare cases have been reported in association with neurofibromatosis type 2 (NF2). A 25-year-old man was admitted for foot drop. He had an asymptomatic skin-colored nodule on his neck that had been present for 10 years. His medical history included local excision of a plexiform schwannoma on his left leg in our dermatology clinic 6 years prior. A histopathological examination of the skin-colored nodule also showed the typical microscopic features of a plexiform schwannoma, including the characteristic Antoni type A areas showing frequent nuclear palisading and Verocay bodies. Magnetic resonance imaging revealed a meningioma and a vestibular schwannoma in the cranium and multiple neurofibromas on the spinal cord. Herein we report a rare case of cutaneous plexiform schwannomas in a patient with NF2.