Sporadic Malignant Triton Tumor of Shoulder: a Case Report.

Background: Malignant triton tumors (MTT) are subtype of malignant peripheral nerve sheath tumor (MPNST) which develop from Schwan cells of peripheral nerves or within neurofibromas, and shows rhabdomyoblastic differentiation. It is a rare soft tissue tumor with poor prognosis. Objective: We report a case of Malignant Triton Tumor (MTT) arising in the right shoulder in a 46 year old male patient presented to our Musculoskeletal Oncology Clinic at Royal Rehabilitation center at King Hussein Medical Center during June 2018. Case presentation: The patient was complaining of an 8 months long progressive right shoulder pain and swelling at the posterior lateral area of the shoulder. As accurate diagnosis is crucial in such case, investigations that included x-rays and magnetic resonance imaging (MRI) demonstrated an soft tissue tumor involving the right shoulder area leading to the differential diagnosis of aggressive soft tissue tumor which laid down the plan of an open incisional biopsy to be reported histopathological as a case of Malignant Triton Tumor which is a very rare and aggressive sarcoma originates from the peripheral nerve sheaths as it is subtype of malignant peripheral nerve sheath tumors after which excision of the entire tumor with safety margin was performed and referred for adjuvant chemotherapy. Conclusion: The treatment of choice is radical tumor excision with wide margins followed by chemotherapy and /or radiotherapy to improve the 5 years survival rates.

Surgical Treatment of Malignant Peripheral Nerve Sheath Tumor of the Scalp With Intracranial and Extracranial Extension: A Rare Case Report.

ABSTRACT: Malignant peripheral nerve sheath tumors of the scalp are rare neoplasms of the peripheral nervous system. Here, we describe an unusual malignant peripheral nerve sheath tumor of the scalp in an 84-year-old Asian man. The tumor was associated with bony destruction, intracranial, and extracranial extension. Trans-arterial embolization was done twice preoperatively. En block excision was performed and the dura and soft tissue defect were reconstructed by anterolateral thigh free fasciocutaneous flap. There is no recurrence and the wound healed well during follow-up.

Surgical management of malignant melanotic nerve sheath tumors: an institutional experience and systematic review of the literature.

OBJECTIVE: Malignant melanotic nerve sheath tumors are rare tumors characterized by neoplastic melanin-producing Schwann cells. In this study, the authors report their institution's experience in treating spinal and peripheral malignant melanotic nerve sheath tumors and compare their results with the literature. METHODS: Data were collected from 8 patients who underwent surgical treatment for malignant melanotic nerve sheath tumors between 1996 and 2023 at Mayo Clinic and 63 patients from the literature. Time-to-event analyses were performed for the combined group of 71 cases to evaluate the risk of recurrence, metastasis, and death based on tumor location and type of treatment received. Unpaired 2-sample t-tests and Fisher's exact tests were used to determine statistical significance between groups. RESULTS: Between 1996 and 2023, 8 patients with malignant melanotic nerve sheath tumors underwent surgery at the authors' institution, while 63 patients were identified in the literature. The authors' patients and those in the literature had the same mean age at diagnosis (43 years). At the authors' institution, 5 patients (63%) experienced metastasis, 6 patients (75%) experienced long-term recurrence, and 5 patients (62.5%) died. In the literature, most patients (60.3%) were males, with a peak incidence between the 4th and 5th decades of life. Nineteen patients (31.1%) were diagnosed with Carney complex. Nerve root tumors accounted for most presentations (n = 39, 61.9%). Moreover, 24 patients (38.1%) had intradural lesions, with 54.2% (n = 13) being intramedullary and 45.8% (n = 11) extramedullary. Most patients underwent gross-total resection (GTR) (n = 41, 66.1%), followed by subtotal resection (STR) (n = 12, 19.4%), STR with radiation therapy (9.7%), and GTR with radiation therapy (4.8%). Sixteen patients (27.6%) experienced metastasis, 23 (39.7%) experienced recurrence, and 13 (22%) died. Kaplan-Meier analyses showed no significant differences among treatment approaches in terms of recurrence-free, metastasis-free, and overall survival (p > 0.05). Similar results were obtained when looking at the differences with respect to intradural versus nerve root location of the tumor (p > 0.05). CONCLUSIONS: Malignant melanotic nerve sheath tumors are rare tumors with a high potential for malignancy. They carry a dismal prognosis, with a pooled local recurrence rate of 42%, distant metastasis rate of 27%, and mortality rate of 26%. The findings from this study suggest a trend favoring the use of GTR alone or STR with radiation therapy over STR alone. Mortality was similar regardless, which highlights the need for the development of effective treatment options to improve survival in patients with melanotic schwannomas.

Other Nerve Sheath Tumors of Brain and Spinal Cord.

The three main types of nerve sheath tumors are schwannomas, neurofibromas and perineuriomas. Multiple neurofibromas throughout the body are the hallmark of Neurofibromatosis type 1 (NF1). Spinal nerve sheath tumors are classified in the group of intradural extramedullary spinal cord tumors, in which they are the most common type (25-30%). Their incidence is 3-4 per 1 million people. Spinal schwannomas are encountered sporadically or in the context of Neurofibromatosis type 2, while neurofibromas are typical for patients with Neurofibromatosis type 1. Neurofibromas are composed predominantly of Schwann cells and fibroblasts, alongside which are also found axons, perineurial cells, mast cells and extracellular matrix. Most of the neurofibromas are asymptomatic. Any increase in the size of a neurofibroma or the presence of pain is an indicator of a possible malignant degeneration. Neurofibromas are treated surgically. Neurofibromas involve the whole nerve and cause its fusiform enlargement which makes it impossible to preserve the nerve's functions if complete tumor removal is performed. Hence, such tumors are initially observed. In case of progressive growth, the options are either resection of the tumor and immediate reconstruction with a peripheral nerve graft (e.g., nerve suralis interposition graft) or subtotal removal and follow-up. Malignant peripheral nerve sheath tumors (MPNST) are very rare tumors with incidence of around 1 per 1,000,000 people. MPNST account for 3-10% of all soft-tissue sarcomas. The most common initial symptom of MPNST is a painless mass. Any rapid increase in a subcutaneous mass or rapid onset of symptoms should raise the suspicion of a malignant tumor. In patients with diagnosed NF1, the recent rapid increase in a known lesion should raise the suspicion of malignant degeneration of the lesion and opt for active treatment. In the case of MPNST a wide surgical excision is advocated. The resectability depends greatly on the location of the tumors and varies from around 20% in paraspinal MPNST and reaches 95% in MPNST localized in the extremities. MPNST are a rare disease and should be managed by a multidisciplinary team of neurosurgeons, radiologists and oncologists.

Primary de novo malignant peripheral nerve sheath tumor of the breast mimicking mastitis. Report of a case and review of the literature.

Malignant peripheral nerve sheath tumor (MPNST) is a rare tumor representing <0.1% of malignant breast tumors. Here, we report a case of sporadic MPNST of the breast in a 45-year-old woman with a fast-evolving painful mass in the right breast associated with edema, redness, and increased local temperature, simulating mastitis. This presentation has not been reported. A review of the literature since 1992 has revealed 15 MPNST cases, including the present one with sufficient data for analysis. All the cases were women. The ages ranged from 16-60 years (mean 40.5 years). Duration of symptoms varied from four days to 15 years (mean 2.7 years). Tumor size ranged from 2.5-30 cm (mean 10.9 cm). 64.3% of tumors were well-circumscribed. Tumors were graded as grade 1 (7.7%), grade 2 (38.5%), and grade 3 (53.8%). Three (20%) cases showed histopathological peculiarities. Simple mastectomy was performed in four (26.7%) cases, radical mastectomy in six (40%) cases, and simple excision in five (33.3%) cases. There were no metastases in the six cases where axillary dissection was performed. Seven (53.8%) patients received adjuvant therapy, including chemotherapy and∕or radiotherapy. Local recurrence was observed in two (16.7%) patients. Distant metastasis was detected in one patient (7.7%) affecting the lung 11 months after radical mastectomy. The follow-up was available for 10 patients (mean 2.2 years, median 1 year). One patient (10%) died of the disease. At the last follow-up, 80% of patients were still alive. The main differential diagnosis includes nonpleomorphic spindle cell tumors.

Malignant peripheral nerve sheath tumours in a patient with Neurofibromatosis-1.

Malignant peripheral nerve sheath tumour (MPNST) is an uncommon type of soft tissue tumour which most commonly arises in the setting of Neurofibromatosis-1 (NF-1) or in the presence of another nerve sheath tumour. NF-1 is an autosomal dominant syndrome which is diagnosed based on clinical criteria. People suffering from NF-1 are at a higher risk of developing tumours, especially MPNST. MPNST can occur anywhere along the distribution of nerve roots but most commonly involves the limbs and trunk. The prognosis of MPNST in the setting of NF-1 is grave as the distant metastasis develops earlier than non-syndromic cases. Pre-operative diagnosis is difficult as there is no gold standard radiologic technique or characteristic radiological features. The diagnosis is established after histological evaluation supplemented by immunohistochemistry of the tumour tissue. We present a case of a 38-year-old female, a known case of NF-1, who presented with a single, irregular, cystic swelling in the left flank which was increasing in size. The patient underwent complete surgical excision of a 6cm tumour which was diagnosed as MPNST after histopathological examination. The rare nature of this tumour makes the diagnosis and treatment extremely hard. Awareness regarding this disease should be increased so that proper treatment plans can be made.

Experience of a single center in the treatment of rare malignant peripheral nerve sheath tumors during the years 1991-2021.

Malignant peripheral nerve sheath tumor (MPNST) is a rare sarcoma with a poor prognosis, as the aggressive types of this cancer tend to grow rapidly and metastasize frequently. MPNST is associated with neurofibromatosis type 1 gene mutation. The minority of cases arise secondary to radiation therapy or sporadically. The primary treatment for MPNST is early surgical resection of the tumor. The aim of this study was to retrospectively evaluate the outcome of the treatment of MPNST in Helsinki University Hospital from the years 1991 to 2021. Fourteen MPNST cases were evaluated in this study retrospectively. Descriptive statistical analysis was performed on the collected patient data. Marginal resection was completed in nine cases, wide margins were achieved in three cases, and in two cases the final histological examination of the specimen revealed intralesional removal. During the follow-up time of 36.7 ± 12.1 months, all patients who underwent wide margin resection were alive. One patient died 22 months after intralesional resection and six within 38.3 ± 30.9 months of marginal resection. Seventy-one percent of tumor surgeries resulted in Clavien-Dindo class 3b complications, reflecting the complexity of the surgeries. The aggressive nature of MPNST and the large size of these tumors requires extensive surgery, which can lead to complications. The prognosis of MPNST needs improvement.

Lumbar malignant peripheral nerve sheath tumor: a rare case in a young patient.

Malignant peripheral nerve sheath tumor (MPNST) is a rare soft tissue sarcoma that originate from peripheral nerves or from cells associated with the nerve sheath. We report the case of a 30­year­old male patient with a history of neurofibromatosis type I (NF-1) and a MPNST located in the lumbar region. The mass was resecated but surgical margins weren't clear. Recurrence of disease was observed after few months. A close monitoring of subjects with NF-1 is crucial to diagnose MPNST at an earlier stage and allow a complete surgical resection.

Cirugía de los tumores neurales del sacro / Surgery of neurogenic tumors of the sacrum

Nuestro objetivo es compartir nuestra experiencia en tumores neurogénicos del área sacra, una patología infrecuente, valorando las vías de abordaje, técnicas intraoperatorias, complicaciones y evolución de los pacientes en una serie de casos. Métodos: Realizamos un análisis retrospectivo de 19 casos de tumores neurogénicos de la región sacra diagnosticados y operados en nuestro centro, de los cuales ocho eran hombres y 11 mujeres, registrando una edad media al diagnóstico de 51 años (con un rango de edades entre 25 y 78 años). Seis se encontraban asintomáticos y fueron diagnosticados incidentalmente, mientras que la mayoría (11 pacientes) presentaban dolor lumbar acompañado de otros síntomas: dolor irradiado a miembros inferiores (MMII), dolor pélvico, alteraciones sensitivas y pérdida de fuerza en MMII. Dos pacientes presentaban otro síntoma principal al diagnóstico: dolor pélvico y en miembro inferior izquierdo (MII). A todos los pacientes se les realizó como mínimo una prueba de imagen (RM/TC). Nueve pacientes tenían tumores limitados al sacro o con extensión posterior, practicándose una intervención por vía posterior. En seis se realizó un abordaje exclusivamente por vía anterior debido a la localización presacra de la tumoración; y en cuatro de ellos fue preciso un abordaje tanto anterior como posterior. Resultados: Los seis pacientes asintomáticos al diagnóstico continuaron sin síntomas tras la intervención. En ocho desaparecieron los síntomas después de la cirugía, y al alta cuatro presentaron dolor lumbar o de miembros que mejoró en consultas sucesivas. Una paciente presentó clínica consistente en déficit motor y sensitivo en el miembro inferior derecho derivada de la afectación del nervio ciático poplíteo externo. El tiempo medio de seguimiento fue de 69 meses (desde seis hasta 178 meses) (AU)

Our objective is to share our experience in neurogenic tumors of the sacral area, an uncommon disease, and assess approaches, intraoperative techniques, complications and clinical course of patients in a case series. Methods: We conducted a retrospective analysis of 19 cases of patients with neurogenic tumors in the sacral area who were diagnosed and underwent surgery at our center. Of them, 8 were male and 11 were female. They had a mean age at diagnosis of 51 years (with an age range of 25-78 years). Six patients were asymptomatic and were diagnosed incidentally, while the majority (11 patients) presented with lumbar pain accompanied by other symptoms: pain radiating to the legs, pelvic pain, sensory alterations and loss of strength in the legs. Two patients presented with another primary symptom on diagnosis: pain in the pelvic region and in the left leg. All patients underwent a least one imaging test (MRI/CT scan). Nine patients had tumors limited to the sacrum or with subsequent spread, with surgery via the posterior route. In 6 cases, an exclusively anterior approach was employed owing to the pre-sacral location of the tumor; 4 cases required both an anterior and posterior approach. Results: The 6 patients who were asymptomatic at diagnosis continued to have no symptoms after surgery. In 8 patients, symptoms resolved after surgery, and at discharge 4 had pain in the lumbar region or legs, which improved in subsequent consultations. One patient had symptoms consistent with motor and sensory deficit in the right leg deriving from impairment of the external popliteal sciatic nerve. The mean follow-up period was 69 months (6-178 months) (AU)

Malignant peripheral nerve sheath tumor of the orbit: a case report and review of the literature.

Malignant peripheral nerve sheath tumor is a rare tumor which infrequently involves the orbit. They occur most often in the setting of neurofibromatosis 1 (NF1), and therefore the involvement of the orbit without a history of NF1 is even less common. Management of this tumor is fraught with a high rate of recurrences and metastases, with a high mortality rate. Primary surgical excision with tumor-free margins remains the primary treatment, while adjuvant modalities such as radiation and chemotherapy play a more minor role.

The clinical course and role of surgery in pediatric malignant peripheral nerve sheath tumors: a database study.

OBJECTIVE: Malignant peripheral nerve sheath tumors (MPNSTs) are rare tumors found throughout the body, with their clinical course in children still not completely understood. Correspondingly, this study aimed to determine survival outcomes and specific clinical predictors of survival in this population from a large national database. METHODS: All patients with MPNSTs aged ≤ 18 years in the US National Cancer Database (NCDB) between 2005 and 2016 were retrospectively reviewed. Data were summarized, and overall survival was modeled using Kaplan-Meier and Cox regression analyses. RESULTS: A total of 251 pediatric patients with MPNSTs (132 [53%] females and 119 [47%] males) were identified; the mean age at diagnosis was 13.1 years (range 1-18 years). There were 84 (33%) MPNSTs located in the extremities, 127 (51%) were smaller than 1 cm, and 22 (9%) had metastasis at the time of diagnosis. In terms of treatment, surgery was pursued in 187 patients (74%), chemotherapy in 116 patients (46%), and radiation therapy in 129 patients (61%). The 5-year overall survival rate was estimated at 52% (95% CI 45%-59%), with a median survival of 64 months (range 36-136 months). Multivariate regression revealed that older age (HR 1.10, p < 0.01), metastases at the time of diagnosis (HR 2.14, p = 0.01), and undergoing biopsy only (HR 2.98, p < 0.01) significantly and independently predicted a shorter overall survival. Chemotherapy and radiation therapy were not statistically significant. CONCLUSIONS: In this study, the authors found that older patient age, tumor metastases at the time of diagnosis, and undergoing only biopsy significantly and independently predicted poorer outcomes. Only approximately half of patients survived to 5 years. These results have shown a clear survival benefit in pursuing maximal safe resection in pediatric patients with MPNSTs. As such, judicious workup with meticulous resection by an expert team should be considered the standard of care for these tumors in children.

Morbidity and Function Loss After Resection of Malignant Peripheral Nerve Sheath Tumors.

BACKGROUND: Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive soft tissue sarcomas. Their resection may lead to serious morbidity. Incidence of postoperative motor and sensory deficits is unknown, and reconstruction aimed at restoring such deficits is infrequently carried out. OBJECTIVE: To identify the incidence and risk factors of postoperative morbidity in MPNST as well as the use and outcomes of functional reconstructions in these patients. METHODS: Postoperative function and treatment of MPNSTs diagnosed from 1988 to 2019 in 10 cancer centers was obtained. Two models were constructed evaluating factors independently associated with postoperative motor (

A rare case report of malignant peripheral nerve sheath tumor involving both the small bowel and large bowel.

Malignant peripheral nerve sheath tumor (MPNST) contains properties and histologic markers of both neural crest cells and mesenchymal cells. It is a rare diagnosis, with an incidence of 1:100,000/year or 4%-10% of soft-tissue sarcomas. There are very few cases reported and studied. Therefore, establishing a proper diagnosis and treatment of MPNST provides a challenge. We present this unique and rare case of metastatic MPNST of the small and large bowel with bone, pulmonary, liver, and splenic metastases. The patient subsequently developed hemorrhagic brain metastases and died 6 months after THE initial diagnosis.

Résumé La tumeur maligne de la gaine nerveuse périphérique (MPNST) contient des propriétés et des marqueurs histologiques des cellules de la crête neurale et du mésenchyme cellules. Il s'agit d'un diagnostic rare, avec une incidence de 1: 100 000 / an ou 4 à 10% des sarcomes des tissus mous. Il y a très peu de cas signalés et étudié. Par conséquent, l'établissement d'un diagnostic et d'un traitement appropriés de la MPNST constitue un défi. Nous présentons ce cas unique et rare de MPNST métastatique du petit et du gros intestin avec métastases osseuses, pulmonaires, hépatiques et spléniques. Le patient a ensuite développé métastases cérébrales hémorragiques et est décédé 6 mois après LE diagnostic initial.

Primary intraosseous malignant peripheral nerve sheath tumor of the mandible: An unusual presentation mimicking a benign lesion.

The malignant peripheral nerve sheath tumor (MPNST) is a rare, aggressive malignant tumor that usually develops in the context of neurofibromatosis type 1. In the oral cavity, these tumors are excelling rare, especially in intraosseous sites. Herein, we report an unusual presentation of intraosseous MPNST affecting the mandible posterior region in a 28-year-old male without neurofibromatosis type 1 discovered as an incidental find on imaging exam. CT scan evaluation showed a solitary, well-defined, round hypodense lesion in the posterior mandibular region extending from tooth 45 to 46. Microscopic evaluation showed a tumor composed of atypical spindle-shaped cells arranged in fascicles and a storiform pattern. Tumor cells were positive for S-100 protein. Epithelial membrane antigen (EMA), pan-cytokeratin AE1/AE3, desmin, alpha-smooth muscle actin (α-SMA), HMB-45, MART-1, MUC4, and CD56 were negative. The diagnosis was low-grade MPNST. The patient underwent wide surgical resection of the tumor. After three years of follow-up, the patient remained with no evidence of recurrence or metastatic disease. When an intraosseous neurogenic tumor is suspected based on radiological characteristics, despite the apparent benign nature, an incisional biopsy is mandatory to rule out malignancy before treatment planning to avoid inadequate conservative treatment.

Endoscopic Endonasal Surgery for Resection of a Pterygopalatine Fossa Malignant Peripheral Nerve Sheath Tumor: 2-Dimensional Operative Video.

The pterygopalatine fossa (PPF) is an inverted, pyramid-shaped space immediately behind the posterior wall of the maxillary sinus, and lesions arising here include juvenile angiofibromas, schwannomas, and, in exceptionally rare cases, malignant peripheral nerve sheath tumors.1,2 Surgical access to the PPF is challenging and has been historically achieved via an open transmaxillary approach associated with facial scaring/deformity as well as potential injury to facial and infraorbital nerve branches.3 We present the case of a 67-year-old woman with facial numbness secondary to a presumed trigeminal schwannoma in the right PPF on magnetic resonance imaging. This surgical video highlights the key stages in performing an endoscopic endonasal excision of a PPF tumor. We start with a wide medial maxillary antrostomy, mobilization of the inferior turbinate, ethmoidectomy, and sphenoidotomy. The posterior wall of the maxillary sinus is then lifted off the anterior aspect of the tumor. The soft tissue attachment medial to the tumor containing the sphenopalatine artery is then cauterized and divided. This is followed by circumferential blunt dissection of the tumor until it is sufficiently mobile to remove in a piecemeal fashion. The PPF is then examined for any residual tumor and any bleeding from the maxillary artery within the fat pad. Hemostasis and reattachment of the inferior turbinate into the lateral nasal wall is demonstrated. The patient did not have any new deficits postoperatively, but histology indicated a malignant peripheral nerve sheath tumor and she underwent postoperative proton beam therapy. Postoperative surveillance magnetic resonance imaging at 14 months showed no tumor recurrence. The patient consented to the procedure in a standard fashion (Video 1).

A giant posterior mediastinal malignant peripheral nerve sheath tumor and benign neurofibroma in body surface: a case report.

BACKGROUND: Neurofibromatosis comprises neurofibromatosis type 1 (NF1) and type 2 (NF2). Major tumor type of NF1 are neurofibroma recognized as benign peripheral nerve tumor, malignant peripheral nerve sheath tumor (MPNST), and glioma. CASE PRESENTATION: We report a woman with a special condition, whose tumors in body surfaces were benign neurofibroma and tumors in posterior mediastinum are MPNST. The chest-enhanced CT suggested a round soft tissue density in posteriormediastium. The diagnosis was established by pathology and immunohistochemistry. A single-stage thoracoscopic mediastinal mass resection was performed. The whole operation went smoothly and the CT scan of lungs did not show relapse of tumor three months later. CONCLUSIONS: The appearance of neurofibroma should draw particular attention to the possibility of developing MPNST. More careful imaging examinations should be carried out, and pathological examination could diagnose it.

Radical Exenteration of the Skull Base for End-Stage, Locally Advanced Sinonasal Malignancies: Challenging the Dictum of Unresectability.

BACKGROUND: The role of surgery is not well defined in locally advanced sinonasal cancers with intracranial involvement after all medical options have been exhausted. We hypothesize that patients whose tumors are deemed unresectable and referred to palliative care may benefit from radical salvage surgery. METHODS: We performed a single-center retrospective review of patients with malignant, locally advanced (stage T4b) sinonasal cancers with intracranial involvement from 2000 to 2020, inclusive. Data were collected on the patient demographics, details of chemotherapy, radiation, histology, perioperative complications, surgical approaches, and survival. We compared the survival outcomes of patients with different duration of disease before presentation. RESULTS: We identified 17 patients who had undergone salvage surgical resection of treatment-recalcitrant, locally advanced sinonasal tumors. Almost all patients had undergone prior surgery, radiotherapy, and chemotherapy. Perioperative complications occurred in 6 of 17 patients with 1 death. Patients with clinically less aggressive disease had significantly longer progression-free and overall survival compared with the more aggressive group. CONCLUSIONS: Salvage surgery for locally advanced sinonasal cancers with intracranial invasion that is recalcitrant to all other therapies should be considered for patients who otherwise have no other treatment options.

Neurofibrosarcoma Revisited: An Institutional Case Series of Uterine Sarcomas Harboring Kinase-related Fusions With Report of a Novel FGFR1-TACC1 Fusion.

Uterine sarcomas with variable CD34 and S100 expression represent an emerging class of tumor in the female genital tract which commonly presents in the endocervix of premenopausal women. Initial molecular characterization identified NTRK1 and NTRK3 gene fusions as oncogenic drivers in these tumors; however, the repertoire of genetic alterations is likely more diverse given the recent discovery of PDGFB and RET gene fusions in similarly described tumors. Importantly, these fusion events lead to the aberrant activation of kinases that are potentially therapeutically targetable; therefore, recognizing this class of tumor becomes critical for initiating the molecular testing required for an accurate diagnosis and identification of clinically actionable fusions. Here, we report our institutional experience with 12 cases of uterine spindle cell sarcomas harboring kinase-related fusions. Patients ranged from 21 to 80 years old (median, 38 y) and presented either asymptomatically or with pelvic pain and/or uterine bleeding. Eleven (92%; 11/12) tumors were localized to the cervix and 1 (8%; 1/12) tumor was localized in the anterior fundus of the uterine corpus. Tumors ranged in size from 1.5 to 15.0 cm (median, 6.0 cm) and were histologically characterized by a moderately cellular, infiltrative proliferation of spindle cells with features of benign gland entrapment, stromal collagen deposition, perivascular hyalinization, occasionally myxoid stroma, a lymphocytic infiltrate, occasional nuclear pseudoinclusions, and a pseudophyllodes architecture. RNA-sequencing identified NTRK1 (8/12), NTRK3 (1/12), and PDGFB (2/12) gene fusions, which have been previously implicated in this tumor class, as well as a novel FGFR1-TACC1 (1/12) fusion. All tumors in this cohort showed coexpression of CD34 and S100 by immunohistochemistry except for those tumors with PDGFB fusions which showed solely CD34 expression. Of the 10 surgically resected tumors with follow-up, outcomes best correlated with the stage of disease. One of 4 patients with stage IA tumors (1/4) had recurrences, half of the stage IB (2/4) tumors had recurrences and all of the stage IIB tumors (2/2) had recurrences and died of disease. Future studies are still required to better understand the spectrum of genetic alterations as well as evaluate the efficacy of targeted kinase inhibitors in this class of tumor.

Recurrent malignant peripheral nerve sheath tumor of the parietal scalp.

Malignant peripheral nerve sheath tumors (MPNSTs) are a rare and aggressive subtype of sarcomas defined by their neural origin. Head and neck manifestations are particularly uncommon. Challenges exist in diagnosis, management, and recurrence. Achieving local control, particularly in the head and neck region, is difficult. We present a patient with a rapidly enlarging MPNST on the right parietal calvarium shortly after resection of a right vagus nerve MPNST. Recommendation was made for excision and reconstruction with a local advancement flap followed by radiation therapy. Local control with good aesthetic outcome was achieved by applying recommended surgical and oncologic principles.