Head and Neck Soft Tissue Sarcomas: A Multivariate Analysis of Outcomes

Head-and-neck dermatofibrosarcoma protuberans: Survival analysis and Clinically relevant immunohistochemical indicators

BACKGROUND

Head and neck dermatofibrosarcoma protuberans (HNDFSP) is extremely rare and not entirely understood.

OBJECTIVE

To investigate the clinicopathological features of HNDFSP and identify the expression of its clinically relevant indicators, with the expectation of improving the existing treatment strategies.

METHODS

A long-term follow-up of patients with HNDFSP who received treatment between 2000 and 2021 at Shanghai Ninth People's Hospital was conducted. The clinical, histological, and immunohistochemical data of the patients were retrieved and analyzed. The endpoint of the study was the incidence of significant disease-related clinical events (recurrences or metastasis).

RESULTS

A total of 49 patients with HNDFSP were included in the study, with males (92.7%) predominating than females (7.3%). Eighteen patients developed recurrent disease (36.8%) after surgery, and the median time of recurrence was 48 months (interquartile, 20-74 months). Metastasis occurred in two cases (4.1%). Two patients died during follow-up, both with local recurrence, and one of them with intestinal metastasis. Post-operation radiotherapy was administered to eight patients (16.3%) and the effect in local control was remarkable. Age, tumor size, and negative margins with sufficient safety width were the main independent factors affecting the disease-free survival. Several potential targeted therapeutic indicators, including EZH2 (80.0%), EGFR (91.4%), PDGF (97.1%), PD-L1 (77.1%), and VEGF (77.1%), were positively expressed in most tumor samples.

CONCLUSION

HNDFSP is rare, significantly challenging to control locally, and has a worse prognosis with current treatment strategies. Wide local excision and long-term follow-up are needed. Radiotherapy could improve the prognosis of patients with HNDFSP.

International Consensus Statement on Allergy and Rhinology: Sinonasal Tumors

BACKGROUND

Sinonasal neoplasms, whether benign and malignant, pose a significant challenge to clinicians and represent a model area for multidisciplinary collaboration in order to optimize patient care. The International Consensus Statement on Allergy and Rhinology: Sinonasal Tumors (ICSNT) aims to summarize the best available evidence and presents 48 thematic and histopathology-based topics spanning the field.

METHODS

In accordance with prior International Consensus Statement on Allergy and Rhinology documents, ICSNT assigned each topic as an Evidence-Based Review with Recommendations, Evidence-Based Review, and Literature Review based on the level of evidence. An international group of multidisciplinary author teams were assembled for the topic reviews using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses format, and completed sections underwent a thorough and iterative consensus-building process. The final document underwent rigorous synthesis and review prior to publication.

RESULTS

The ICSNT document consists of four major sections: general principles, benign neoplasms and lesions, malignant neoplasms, and quality of life and surveillance. It covers 48 conceptual and/or histopathology-based topics relevant to sinonasal neoplasms and masses. Topics with a high level of evidence provided specific recommendations, while other areas summarized the current state of evidence. A final section highlights research opportunities and future directions, contributing to advancing knowledge and community intervention.

CONCLUSION

As an embodiment of the multidisciplinary and collaborative model of care in sinonasal neoplasms and masses, ICSNT was designed as a comprehensive, international, and multidisciplinary collaborative endeavor. Its primary objective is to summarize the existing evidence in the field of sinonasal neoplasms and masses.

Undifferentiated pleomorphic sarcoma of the floor of mouth: A rare case

Undifferentiated pleomorphic sarcoma (UPS) previously called as malignant fibrous histiocytoma comprises a group of high-grade pleomorphic sarcomas that cannot be otherwise classified and considered as a diagnosis of exclusion. In the head neck region, UPS is extremely rare and accounts for 3% of all the undifferentiated pleomorphic sarcomas. Some of the reported sites include maxilla, mandible, buccal mucosa, temperomandibular fossa, tongue, gingiva, paranasal sinuses, salivary glands, and retro-orbital soft tissue. Undifferentiated pleomorphic sarcoma of the floor of the mouth is very rare. To our knowledge, only one case has been reported earlier. We report the second case of undifferentiated pleomorphic sarcoma of the floor of mouth.

Desmoplastic Small Round Cell Tumor of the Head and Neck: A Potential Diagnostic Pitfall

Primary desmoplastic small round cell tumor (DSRCT) in the head and neck region is extremely rare. There is limited information about its clinicopathological characteristics, prognosis, and treatment modalities. The purpose of this study is to provide a comprehensive review of DSRCT occurring primarily in the head and neck, to demonstrate its peculiar morphology and immunohistochemical expression, and to address the differential diagnoses. A total of 25 cases were collected after a thorough review of the relevant literature. DSRCT was most frequently reported in the major salivary glands, followed by the eyes. Furthermore, some cases were misinterpreted as poorly differentiated carcinoma, Ewing sarcoma, and olfactory neuroblastoma. Diagnosing DSRCTs in the head and neck can be very challenging due to their rarity in this location, overlapping morphology, and immunohistochemistry. In these cases, following a systemic approach helps to solve diagnostic problems.

Soft Tissue Sarcomas of the Head and Neck Region with Skull Base/Intracranial Invasion: Review of Surgical Outcomes and Multimodal Treatment Strategies: A Retrospective Case Series

Soft tissue sarcomas (STS) invading the skull base are rare with little data to guide surgical management. Here we aimed to determine the factors affecting tumor control rates and survival in patients with T4 stage head and neck STS involving the skull base. A retrospective review of STS patients, surgically treated at our institution between 1994 and 2017 was conducted. Variables were collected and assessed against progression-free survival. Tumors were graded using the Fédération Nationale des Centres de Lutte Contre le Cancer (FNCLCC) system. A total of 51 patients (mean age of 35) were included, of whom 17 (33.3%) patients were FNCLCC grade 1, 8 (15. 7%) were FNCLCC grade 2 and 26 (51%) were FNCLCC grade 3. The median PFS was 236.4 months while the 5- and 10-year PFS rates were 44% and 17%, respectively. Recurrence occurred in 17 (33.3%) patients. Local recurrence occurred in 10 (58.8%). Univariate analysis revealed R0 resection had a near-significant impact on tumor control in radiation-naïve patients. Otherwise, prior radiation (HR 6.221, CI 1.236–31.314) and cavernous sinus involvement (HR 14.464, CI 3.326–62.901) were negative predictors of PFS. The most common cause of treatment failure was local recurrence. In T4 stage head and neck STS with skull-base involvement, FNCLCC grade, radiation status, and anatomic spread should be considered in determining the overall treatment strategy.

Angiosarcomas of the head and neck: Impact of large data analysis on clinical management

Angiosarcoma is a rare but often fatal malignancy from blood and lymphatic vessels that can arise anywhere in the body and often affects the head and neck region. Although its dismal prognosis is predominantly explained by its aggressive biology, several secondary factors contribute to poor outcomes. These include a phenotypic resemblance to innocuous blood vessel lesions, which contributes to a significant degree of late diagnosis. Another important factor is the rarity of angiosarcoma, which has impaired scientific determination of its optimal treatment significantly. As a result, treatment of angiosarcomas has largely been guided by information derived from the study of sarcomas at large, themselves a highly heterogeneous group of mesenchymal cancers both from a diagnostic as well as therapeutical perspective. The Digital Revolution and resultant Information Age promise to focus the clinical management of rare cancers from a generic to a more customized approach. In this paper, we review the current understanding of head and neck angiosarcomas within the context of this process.

Anterior Skull Base Sarcomas: Report of Characteristics and Outcomes at a Tertiary Care Cancer Center

Objective This study was aimed to describe our institutional experience on characteristics and treatment outcomes of sinonasal sarcomas invading the anterior skull base.

Design Present study is a retrospective review.

Setting The study was conducted at an academic cancer care center.

Participants Thirty-one patients with skull base sarcomas treated with primary surgery from 1979 to 2015 were identified for this study from a preexisting database.

Main Outcome Measures Survival and recurrence outcomes using the Kaplan–Meier method were the focus areas of the study.

Results The median age was 44 years (range: 13–69 years). Twenty patients were male (64.5%). Twenty-nine patients underwent open craniofacial resection (93.5%) and two patients underwent endoscopic resection (6.5%). The majority of tumors were staged pT4 (77.4%). The most common pathologies were leiomyosarcoma (19.4%), osteosarcoma (16.1%), and chondrosarcoma (12.9%). Of those with known margin status, 10 patients had positive/close margins (32.2%) and 16 patients had negative margins (51.6%). Most tumors were high grade (74.2%). Twenty-three patients (74.2%) received adjuvant radiation and four patients (12.9%) received adjuvant chemotherapy. There were nine postoperative complications (29%) including one mortality and three cerebrospinal fluid leaks. There were 10 local, 2 regional, and 5 distant recurrences over a median follow-up of 74 months (range: 1–300 months). The 5-year disease-specific survival (DSS) was 69.8%. The 5-year locoregional recurrence-free probability (RFP) was 63.2% and the 10-year distant RFP was 71.7%. The 5-year DSS for high grade tumors was 64.2 and 85.7% for low grade tumors (p = 0.117).

Conclusion This study contributes an updated analysis of anterior skull base sarcomas. Five-year DSS is approximately 70%. Analysis of survival outcomes based on grade, tumor size, and other factors is limited by small sample size and the rarity of these tumors.

Internal Jugular Venous Extension of a Mandibular Osteosarcoma With Literature Review

Head and neck osteosarcomas (HNOS) account for less than 1% of all head and neck cancers and makeup 6-10% of all primary osteosarcomas. Mandibular osteosarcomas are the second most common subtype of HNOS. They demonstrate higher recurrence rates; however, are amenable to surgery. An 18-year-old male presented with a 2 cm x 3 cm x 2 cm intraoral mass for two months. Biopsy revealed chondroblastic osteosarcoma. Computed tomography revealed extension into the left internal jugular vein. Composite resection of the left mandible, floor of the mouth, ventral tongue, submandibular gland, and modified radical neck dissection with fibular flap repair was performed. Adjuvant chemotherapy and palliative radiotherapy were added. Unfortunately, progressive metastasis to the contralateral mandible and entire spinal cord ensued. We report the first case of head and neck osteosarcoma with intravascular invasion into the internal jugular vein.

Pretreatment tumor sampling and prognostic factors in patients with soft-tissue sarcoma of the head and neck

BACKGROUND

Insufficient preoperative work-up and consequent intralesional or marginal resection of soft-tissue sarcomas of the head and neck (STSHNs) is common.

METHODS

This retrospective cohort study comprised 63 patients with STSHN treated at the Helsinki University Hospital between 2005 and 2017. We assessed the effect of pretreatment tumor sampling on surgical margin status and need for supplemental surgery, as well as prognostic factors and survival.

RESULTS

The lack of representative pretreatment biopsy specimen was associated with unfavorable margin status. Primary surgery at a non-academic center was associated with need for supplemental surgery. The 3-year overall survival (OS) was 68%, disease-specific survival (DSS) 71%, and recurrence-free survival (RFS) 61%. Higher tumor grade and primary tumor size over 5 cm were associated with reduced DSS.

CONCLUSIONS

Diagnosis and management of STSHNs should be centralized to experienced academic centers. Decision-making between needle biopsy, open biopsy, or upfront radical surgery depends on tumor location and size.

Biphenotypic sinonasal sarcoma: Report of 3 cases with a review of literature

Biphenotypic sinonasal sarcoma (BSNS) is a rare recently described distinct spindle cell sarcoma which arises exclusively in the sinonasal region and is characterized by concomitant neural and myogenic differentiation. Before this neoplasm was characterized, most were classified as other entities including adult fibrosarcoma, monophasic synovial sarcoma and malignant peripheral nerve sheath tumor. By immunohistochemistry, these tumors characteristically express S100 and smooth muscle actin (SMA) and/or muscle specific actin (MSA). Most cases harbor rearrangements of PAX3 (paired box gene 3), and the most frequent translocation partner is MAML3 (mastermind like transcriptional coactivator 3). Herein, we described three cases of BSNS involving the nasal cavity with or without paranasal sinus involvement. We also did a literature review of the clinical features, histologic and immunophenotypic findings, cytogenetics, pathogenesis and behavior of this rare entity.

Understanding giant cell sarcoma of the head and neck: A population-based study

BACKGROUND

Giant cell sarcomas (GCS) are rare head and neck neoplasms.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was analyzed for all patients who have been diagnosed with GCS from 1973 to 2014.

RESULTS

Four hundred and forty cases of GCS of the head and neck were identified. The average age at diagnosis was 74.4 years, 86.8% were white, 82.5% were male, 70.7% were insured, and 88.2% lived in an urban metropolitan region. Connective tissue was the most frequent primary site (42.5%). The 5Y-DSS rate was 91.1%, while the 5Y-OS was 54.6% for all cases. Patients treated with surgery alone had the highest 5Y-DSS rate of 94.5. T-classification odds ratio was a significant predictor of survival accounting for confounding variables on multivariate analysis.

CONCLUSIONS

GCS presents most frequently in connective tissue of the head and neck with overall high probability of survival. The treatment of choice is surgery alone.

RREB1-MKL2 fusion in a spindle cell sinonasal sarcoma: biphenotypic sinonasal sarcoma or ectomesenchymal chondromyxoid tumor in an unusual site?

Biphenotypic sinonasal sarcoma (BSNS) is a rare, low grade spindle cell sarcoma, recently recognized in the WHO classification of head and neck tumors, which is characterized by a dual myogenic and neural differentiation and recurrent gene fusions, often involving PAX3-MAML3, and less commonly PAX3 fusions with other partners such as NCOA1, NCOA2, or WWTR1. Yet, in about 4% of tumors no gene rearrangements are identified. Herein, we describe a RREB1-MKL2 fusion in a BSNS lesion occurring in a 73-year-old female patient with a right maxillo-ethmoidal angle lesion. The polypoid, moderately cellular tumor with infiltrative submucosal growth was composed of fascicles of relatively bland spindle cells embedded in a loose collagenous matrix. The tumor cells showed moderate amounts of eosinophilic cytoplasm with indistinct borders and uniform, pale, ovoid to slender nuclei. The slowly proliferating neoplastic cells co-expressed smooth muscle actin and S100, and showed focal nuclear positivity for ß-catenin, while lacking staining for cytokeratins, desmin, myogenin, caldesmon, glial fibrillary acid protein, and SOX-10. Molecular analysis by targeted RNA-based next-generation sequencing identified an in-frame fusion between exon 8 of RREB1 and exon 11 of MKL2, a genetic event that was reported to be a molecular hallmark of ectomesenchymal chondromyxoid tumor. Gene rearrangements in both genes were independently verified by fluorescence in situ hybridization (FISH). To evaluate its recurrent potential an additional group of 15 fusion negative BSNS were tested for abnormalities in RREB1 and MKL2 genes by FISH, but no additional positive cases were identified.

Head and neck sarcomas: treatment outcomes in a tertiary referral center in Argentina

PURPOSE

To analyze the clinical findings, management, and results of oncological treatments and to identify prognostic factors in patients diagnosed with head and neck sarcoma.

METHODS

We performed a retrospective analysis including 48 adult patients with primary head and neck sarcomas, treated between 2006 and 2018 in a referral center of Argentina.

RESULTS

The median follow-up time was 44 months (range: 4-146 months). Five-year overall survival was 68%. On univariate analysis, radiation-induced sarcomas (p=0.038) had worse survival. Five-year disease-free survival was 58% and local recurrence at 2 years was 22.7%. On multivariate analysis, positive/close resection margins (p=0.031), radiation-induced sarcomas (p=0.037), and mandibular and oral cavity location (p=0.002) were independent prognostic factors associated to local recurrence and shorter disease-free survival.

CONCLUSION

Head and neck sarcomas are a rare entity. Surgery is feasible in more than 80% of patients, with an acceptable overall and disease-free survival. Radiation-induced sarcomas, location in the mandible and oral cavity, and close margins were significant prognostic factors in our population.

Radiation Therapy in Adult Soft Tissue Sarcoma-Current Knowledge and Future Directions: A Review and Expert Opinion

Simple Summary

Radiation therapy (RT) is an integral part of the treatment of adult soft-tissue sarcomas (STS). Although mainly used as perioperative therapy to increase local control in resectable STS with high risk features, it also plays an increasing role in the treatment of non-resectable primary tumors, oligometastatic situations, or for palliation. This review summarizes the current evidence for RT in adult STS including typical indications, outcomes, side effects, dose and fractionation regimens, and target volume definitions based on tumor localization and risk factors. It covers the different overall treatment approaches including RT either as part of a multimodal treatment strategy or as a sole treatment and is accompanied by a summary on ongoing clinical research pointing at future directions of RT in STS.

Abstract

Radiation therapy (RT) is an integral part of the treatment of adult soft-tissue sarcomas (STS). Although mainly used as perioperative therapy to increase local control in resectable STS with high risk features, it also plays an increasing role in the treatment of non-resectable primary tumors, oligometastatic situations, or for palliation. Modern radiation techniques, like intensity-modulated, image-guided, or stereotactic body RT, as well as special applications like intraoperative RT, brachytherapy, or particle therapy, have widened the therapeutic window allowing either dose escalation with improved efficacy or reduction of side effects with improved functional outcome. This review summarizes the current evidence for RT in adult STS including typical indications, outcomes, side effects, dose and fractionation regimens, and target volume definitions based on tumor localization and risk factors. It covers the different overall treatment approaches including RT either as part of a multimodal treatment strategy or as a sole treatment, namely its use as an adjunct to surgery in resectable STS (perioperative RT), as a primary treatment in non-resectable tumors (definitive RT), as a local treatment modality in oligometastatic disease or as palliative therapy. Due to the known differences in clinical course, general treatment options and, consequently, outcome depending on lesion localization, the main part of perioperative RT is divided into three sections according to body site (extremity/trunk wall, retroperitoneal, and head and neck STS) including the discussion of special applications of radiation techniques specifically amenable to this region. The review of the current evidence is accompanied by a summary on ongoing clinical research pointing at future directions of RT in STS.

Survival of Patients With Non-Rhabdomyosarcoma Soft Tissue Sarcomas of the Head and Neck

OBJECTIVE

To evaluate factors associated with overall survival (OS) of patients with non-rhabdomyosarcoma soft tissue sarcomas of the head and neck.

STUDY DESIGN

Retrospective cohort study.

METHODS

The National Cancer Database was queried for cases of non-rhabdomyosarcoma soft tissue sarcomas of the head and neck between 2004 and 2014. Cases were categorized according to the World Health Organization classification of soft tissue tumors. A multivariable Cox proportional hazards model was used to evaluate associations with OS.

RESULTS

A total of 4,555 patients (63.6% male, 36.4% female, mean age 59.6 years) met inclusion criteria. The majority of tumors were classified as miscellaneous (35.9%), followed by vascular (20.1%), smooth muscle (13.5%), fibroblastic/myofibroblastic (12.1%), peripheral nerve (8.5%), adipocytic (7.4%), and undifferentiated (2.5%) sarcomas. The mean follow-up was 37.9 months, and overall mortality (MR) was 45.3%. The best prognosis was seen with fibroblastic/myofibroblastic sarcomas (MR = 20.6%, P < .001), whereas vascular sarcomas had the worst prognosis (MR = 67.6%, P < .001). Resection with clear margins had better OS than microscopically positive margins (hazard ratio [HR] = 1.43, P < .001) or grossly positive margins (HR = 2.97, P < .001). Radiation therapy was associated with better OS than no radiation (HR = 0.86, P = .001).

CONCLUSION

Non-rhabdomyosarcoma soft tissue sarcomas of the head and neck are associated with significant mortality. OS differs based on histologic subcategorization. Resection of the primary tumor with clear margins demonstrates improved OS for all histologies, suggesting this modality remains the preferred primary treatment when feasible.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:E500-E508, 2021.

Head and neck sarcomas: the first report addressing the duration of symptoms and diagnostic work up

Background: Head and neck sarcomas are rare and difficult to diagnose and manage.Aim: To describe a population of patients with head and neck sarcomas focusing on the effect of symptom duration and time to diagnosis on mortality and recurrence risk.Materials and methods: Fifty-one patients treated in our department between 1998-2013 were retrospectively included. Patient and tumour characteristics as well as dates of interest were obtained from sarcoma registries, charts and pathology records. The effect of symptom duration and time to diagnosis on mortality and risk of recurrence was tested by multivariate analysis.Results: There was a wide range in symptom duration (1-144 months, median 5) and time for diagnosis (0-234 days, median 14) without significant effect on overall mortality, disease-specific mortality or risk of recurrence. Chondrosarcomas in the larynx dominated among the patients with the longest diagnostic duration.Conclusion and significance: The diagnostic process is challenging and in some cases of extremely long duration without effect on mortality. The symptom duration and time to diagnosis in relation to mortality and risk of recurrence has not previously been described. Early biopsy, better imaging and advanced pathological techniques can hopefully speed up the diagnostic process and reduce morbidity and mortality.

Establishment and characterization of NCC-DFSP3-C1: a novel patient-derived dermatofibrosarcoma protuberans cell line

Dermatofibrosarcoma protuberans (DFSP) is the most common dermal sarcoma; it is characterized by the presence of the COL1A1-PDGFB translocation, which causes the constitutive activation of the platelet-derived growth factor β (PDGFB) signaling pathway. DFSP frequently exhibits local recurrence and is refractory to conventional chemotherapy. Therefore, a novel therapeutic strategy is required for improving the prognosis of DFSP. Although patient-derived cell lines are important tools for pre-clinical studies, currently, only a few such cell lines are available for DFSP in cell banks. Here, we report the establishment of a novel DFSP cell line. Using a surgically resected metastatic tumor tissue from a patient with DFSP, we established a cell line called NCC-DFSP3-C1. The NCC-DFSP3-C1 cells had a COL1A1-PDGFB translocation and retained the same copy number aberrations as the original tumor tissue. NCC-DFSP3-C1 cells exhibited constant growth, spheroid formation, and invasive ability. By screening a drug library, we identified anti-cancer agents with inhibitory effects on the proliferation of NCC-DFSP3-C1 cells; these anti-cancer agents included proteasomal, histone deacetylase, and kinase inhibitors. We concluded that the NCC-DFSP3-C1 cell line may serve as a useful tool for performing basic and pre-clinical studies on DFSP.

The occurrence and pattern of head and neck sarcomas: a comprehensive cancer center experience

PURPOSE

This study aimed to analyze the demographics, clinicopathological, treatment, and survival characteristics of head and neck sarcomas diagnosed in a reference center in the Brazilian Northeast.

MATERIALS AND METHODS

This retrospective cohort study reviewed the clinical records of patients with head and neck sarcomas. Epidemiologic data consisted in clinical location, age, gender, histopathological diagnosis, clinical TNM staging and treatment. Outcome variables were local recurrence and survival. The statistical analyses were performed by a binary logistic regression analysis. The survival analysis was assessed through the Kaplan-Meier curve.

RESULTS

Sixty-nine patients with head and neck sarcomas (male 39; female 30) were analyzed. The most common histologic subtypes were rhabdomyosarcoma, dermatofibrosarcoma, and pleomorphic sarcoma. The mean age of the patients at the time of diagnosis was 38.1 years old. A total of 31 patient died (sarcoma-related death) up to the end of the follow-up, with a mean follow-up rate of 1.63 years. A multivariate analysis revealed that anatomical site, treatment modality, histopathological diagnosis, and clinical stage of the disease were associated with specific survival, reaching statistical significance.

CONCLUSION

This study demonstrates the impact of important clinical-pathological parameters on the overall prognosis of head and neck sarcomas.

Soft tissue head and neck sarcoma: experience of a tertiary referral centre over a 15-year period

BACKGROUND

Head and neck soft tissue sarcoma is uncommon. It is both histologically and clinically heterogeneous, ranging from an indolent, locally destructive tumour, to a locally aggressive neoplasm with metastatic potential.

METHODS

A retrospective review was conducted of all adult head and neck soft tissue sarcomas, including cases of malignant soft tissue sarcoma and all intermediate type tumours, diagnosed between 1997 and 2012.

RESULTS

Sixty-eight cases were identified in this series from the sarcoma multidisciplinary team. Seventeen different histological subtypes of sarcoma were identified. Neither age, gender nor tumour size were significant prognostic indicators for survival in this series.

CONCLUSION

Prognosis is dependent on histological subtype, underscoring the importance of histological classification. Some histological subtypes occur only once or twice in a decade, even within a large regional referral centre. An accumulation of evidence from relatively small case series is key in the long-term development of treatment strategies.

Comparison of prognostic implications between the 7th and 8th edition of AJCC TNM staging system for head and neck soft-tissue sarcoma in adult patients

PURPOSE

This study aimed to investigate the prognostic factors for head and neck soft-tissue sarcoma (HNSTS) in adults, with the comparisons between the 7th and 8th edition of AJCC TNM staging system.

METHODS

From a cancer registry of a single, tertiary referral medical center, the medical records of 67 patients treated from February 2005 to December 2017 were reviewed.

RESULTS

T1b stage by AJCC 7th edition showed most diverse stage migration by AJCC 8th edition, and T1a or T2b stage by 7th edition remained in T1-3 or T3-4 by 8th edition. T2 stage by 7th edition showed a significantly higher death rate than the T1 stage, with fair discrimination in overall survival. Higher histologic grade and angiosarcoma were significant prognostic factors for recurrence as well as overall survival. Also, nodal and distant metastasis worsen overall survival.

CONCLUSIONS

In our series of patients with HNSTS, higher histologic grade, angiosarcoma, N1, and M1 stage significantly increased the risk of recurrence and worse overall survival, which was not evident in revised T stage by AJCC 8th edition.

Low-Grade Fibromyxoid Sarcoma of the Lateral Skull Base: Presentation of Two Cases

Low-grade fibromyxoid sarcoma (LGFMS) is a rare slow-growing malignant tumour with a deceptively benign histologic appearance. Herein, we report two cases of LGFMS with variable clinical presentations. The first case was a 17-year-old female who referred to our department due to deaf ear on the right together with ipsilateral gag reflex impairment and globus sensation in the pharynx. The second case was a 35-year-old female with recurrent LGFMS, suffering from headaches, vertigo, and episodes of loss of consciousness. LGFMS of the temporal bone is a rare pathology, and to the best of our knowledge, no such cases have been reported before.

Using Image-guided Intensity-modulated Radiotherapy on Patients With Head and Neck Soft-tissue Sarcoma

BACKGROUND

Image-guided intensity-modulated radiotherapy (IG-IMRT) is increasingly being used to treat patients with soft-tissue sarcoma (STS) of the head and neck. Although there is no comparison between IMRT and conventional radiation therapy (CRT) concerning their efficacy. In this analysis, we compared CRT and IMRT outcomes for head and neck STS.

PATIENTS AND METHODS

Sixty-seven patients who underwent radiotherapy between 1994 and 2017 were identified.

RESULTS

The median follow-up was 31 months. Of the 67 patients, 34% were treated with CRT technique and 66% with IG-IMRT. The locoregional relapse rate following IMRT was 21% versus 70% with CRT (p<0.001) and the 5-year locoregional control was 69% versus 28%, respectively (p=0.01). IG-IMRT was associated with non-significant, less acute, and chronic adverse events. In the multivariate analysis, a significant influence of radiation technique on locoregional control was confirmed (p=0.04).

CONCLUSION

IG-IMRT seems to be associated both with higher locoregional control as well as lower acute and chronic toxicities.

Validation of Neutrophil Count as An Algorithm-Based Predictive Factor of Progression-Free Survival in Patients with Metastatic Soft Tissue Sarcomas Treated with Trabectedin

Introduction: Based on a mathematical model of trabectedin-induced neutropenia, we assessed the predictive value of absolute neutrophil count (ANC) on progression-free survival (PFS) in an independent validation cohort of patients treated with trabectedin. Methods: We collected data from 87 patients in two expert centers who received at least two cycles of trabectedin for soft tissue sarcomas (STS) treatment. Correlations between ANC, patients' characteristics, and survival were assessed, and a multivariate model including tumor grade, performance status, ANC, and hemoglobin level was developed. Results: Therapeutic ANC ≥ 7.5 G/L level was associated with shorter PFS: 3.22 months (95% confidence interval (CI), 1.57⁻4.87) in patients with ANC ≥ 7.5 G/L vs. 5.78 months (95% CI, 3.95⁻7.61) in patients with ANC < 7.5 G/L (p = 0.009). Age, primary localization, lung metastases, dose reduction, hemoglobin, and albumin rates were also associated with PFS. In multivariate analysis, ANC ≥ 7.5 G/L was independently associated with poor PFS and overall survival. Conclusion: We validated increased pre-therapeutic ANC as a predictive factor of short PFS in patients starting trabectedin for STS. ANC appears to have an impact on survival rates and may be used as a decision-making tool for personalizing second-line strategies in patients with metastatic STS.

Adjuvant radiation for positive margins in adult head and neck sarcomas is associated with improved survival: Analysis of the National Cancer Database

BACKGROUND

Adult head and neck (H&N) sarcomas are a rare malignancy with limited data delineating the role of postoperative radiotherapy (PORT), particularly for a positive surgical margin. There are no randomized trials supporting the use of PORT, therefore treatment trends vary between institutions. A positive margin predicts recurrence and poor survival outcomes. This study uses the National Cancer Database (NCDB) to investigate whether PORT improves overall survival (OS) in adult H&N sarcomas with a positive margin and how utilization has changed.

METHODS

Patients (n = 1142) in the NCDB from 2004-2013 with adult H&N sarcomas who underwent resection and had a positive margin.

RESULTS

Factors significantly associated with increased utilization of PORT were: having insurance, salivary gland primary site, high-risk histology, poor differentiation, and a macroscopic positive margin. Treatment with PORT was associated with improved 5-year OS for all patients with a positive margin (57% vs 48%; P = .002), both microscopic (57% vs 49%; P = .010) and macroscopic (57% vs 41%; P = .036). Improved OS was significant after controlling for other known covariates on multivariate analysis (HR: 0.76; [0.64-0.90]; P = .002). Treatment at a community-based facility was an independent predictor for reduced OS (HR: 1.37; [1.15-1.64]; P < .001). The percentage utilization (53%) of PORT for these patients did not change significantly over time.

CONCLUSION

PORT provides a significant survival benefit for adult H&N sarcoma patients with either a microscopic or macroscopic positive margin; however, PORT is underutilized. Treatment at academic/research cancer programs was associated with increased utilization of PORT and improved survival outcomes.

Academic Facility Utilization and Survival Outcomes in Adult Head and Neck Sarcomas: An NCDB Analysis

Objectives

To investigate clinicopathologic and treatment factors associated with survival in adult head and neck sarcomas in the National Cancer Database (NCDB). To analyze whether treatment settings and therapies received influence survival outcomes and to compare trends in utilization via an aggregated national data set.

Study Design

Prospectively gathered data.

Setting

NCDB.

Subjects and Methods

The study comprised a total of 6944 adult patients treated for a head and neck sarcoma from January 2004 to December 2013. Overall survival (OS) was the primary outcome.

Results

Increased age and tumor size, nodal involvement, and poorly differentiated histology had significantly reduced OS ( P < .001). Angiosarcoma, malignant nerve sheath tumor, malignant fibrous histiocytoma, osteosarcoma, and rhabdomyosarcoma histologic subtypes had significantly reduced OS, while liposarcoma, chondrosarcoma, and chordoma had improved OS ( P < .001). Utilization of surgical therapy was associated with improved OS, while positive surgical margins were associated with treatment at a community-based cancer program and had reduced OS ( P < .001). On multivariate analysis, treatment with radiation and/or chemotherapy was not significantly associated with OS; however, primary treatment with definitive chemoradiotherapy had significantly reduced OS. Patients treated at academic/research cancer programs (n = 3874) had significantly improved 5- and 10-year OS (65% and 54%, respectively) when compared with patients treated at community-based cancer programs (n = 3027; 49% and 29%; P < .001). The percentage utilization of these programs (56% vs 44%) did not change over the study period.

Conclusion

For adult head and neck sarcomas, treatment at an academic/research cancer program was associated with improved survival; however, despite increasing medical specialization, the percentage utilization of these programs for this rare tumor remains constant.

The comparison of predictive factors regarding prognoses and invasion of thymic neuroendocrine tumors preoperatively and postoperatively

Background

Thymic neuroendocrine tumors (TNT), in the anterior mediastinum, are extremely rare diseases which have significantly poor prognoses. Studies have rarely provided conclusive evidence of the prognostic factors of TNT. Standard therapies have been controversial.

Methods

TNT patients (n=173) were enrolled from Surveillance, Epidemiology and End Results database (SEER). Univariate and multivariate analyses were utilized to evaluate predictive factors of prognoses. Logistic regression analysis was used to assess the plausible correlation between histological grade, and cancer invasion. Stratification analysis was used to evaluate the effectiveness of adjuvant therapies.

Results

According to our analysis, local Masaoka stage, surgery, radiotherapy, and non-chemotherapy predicted better overall survival (OS) (P<0.05, for all) in 173 TNT patients. We found that the higher the histological grade of the tumor, the greater the rate of metastasis (P<0.05). The focus was on 125 surgically treated patients, who were females with poor prognostic factors of OS, upgraded histological grade, and advanced Masaoka stage (P<0.01, for all). The effectiveness of radiotherapy treatments had discrepancies at different clinical stages. In the local stage, radiotherapy caused significantly worse OS (P=0.011), while in the advanced stage, patients demonstrated significantly better OS with this treatment (P=0.028). Chemotherapy caused worse OS, primarily, in females (P=0.028).

Conclusions

Surgery, Masaoka stage, and adjuvant treatments were prognostic factors. With surgically treated TNT, gender, histological grade, and Masaoka stage predicted significantly worse OS. Chemotherapy decreased female patients' OS. Radiotherapy significantly promoted advanced and local advanced patients' OS; however, it decreased local stage patients' OS. Predicted TNT invasiveness significantly correlated with histological grade.

Undifferentiated pleomorphic sarcoma of the neck - A case report

Undifferentiated pleomorphic sarcoma very rarely affect the neck. We report a case of a 62year old man who presented with a right sided skin lump which he noticed after sustaining a neck contusion in a road traffic accident about one year ago. The initial CT and ultrasound scans of the lump were suggestive of a thrombosed varix. Clinical examination showed a hard skin nodule with signs of tethering. He underwent a wide excision of the skin nodule and the histology showed undifferentiated pleomorphic sarcoma with margins involved. He subsequently underwent another re-excision of margins and pectoralis major flap reconstruction. Following surgery, he was also prescribed adjuvant radiotherapy and he remains well about 12 months after follow up. The surgical management of undifferentiated pleomorphic sarcoma in the neck is challenging due to the proximity of critical neck structures and the need to obtain clear margins. Thus, adjuvant radiotherapy is often used to improve disease control.

Current update on the diagnosis and management of head and neck soft tissue sarcomas

Head and neck soft tissue sarcomas are a group of rare heterogeneous tumours arising from embryonic mesoderm. They comprise <1% of all head and neck malignancies and 5-15% of all sarcomas with most head and neck sarcomas arising from soft tissues. Although rare, they are associated with both high recurrence and mortality rates. We review the current management of head and neck soft tissue sarcomas.

Head and neck sarcomas: clinical and histopathological presentation, treatment modalities, and outcomes

BACKGROUND

Sarcoma of the head and neck is a rare condition that poses significant challenges in management and often requires radical multimodality treatment.

OBJECTIVES

This study aimed to analyse current clinical presentation, evaluation, management dilemmas and oncological outcomes.

METHODS

Computer records and case notes were analysed, and 39 patients were identified. Variables were compared using Pearson's chi-square test and the log-rank test, while survival outcomes were calculated using the Kaplan-Meier method.

RESULTS

The histopathological diagnosis was Kaposi sarcoma in 20.5 per cent of cases, chondrosarcoma in 15.3 per cent and osteosarcoma in 10.2 per cent. A range of other sarcomas were diagnosed in the remaining patients. The site of disease was most commonly sinonasal, followed by the oral cavity and larynx.

CONCLUSION

Wide local excision with clear resection margins is essential to achieve local control and long-term survival. There is a need for cross-specialty collaboration in order to accrue the evidence which will be necessary to improve long-term outcomes.

Low-Grade Fibromyxoid Sarcoma of the Head and Neck: A Clinicopathologic Series and Review of the Literature

Low-grade fibromyxoid sarcoma (LGFMS) is a deceptively bland malignancy with potential for late recurrence and metastasis, which usually occurs in the deep soft tissues of the extremities and trunk. Most LGFMSs harbor a characteristic gene fusion of FUS-CREB3L2, and recently MUC4 immunostaining has been found to be highly sensitive and specific for the diagnosis. We present a dedicated series of head and neck LGFMS, including the first reported laryngeal case, as well as a review of reported head and neck cases. The surgical pathology archives of our three institutions were searched for cases of LGFMS arising within the head and neck, and four cases were identified. The H&E slides were reviewed, and immunohistochemistry were performed for pancytokeratin, p63, p40, EMA, S100 protein, β-catenin, actin, CD34, and MUC4. The patients were 6, 43, 45, and 73 years old (mean 41.8 years) and included three males and one female. The tumors were located in the posterior cervical spine, facial skin, mandible, and larynx. The tumors were treated with surgical excision, and all four had histologic features typical for LGFMS including alternating myxoid and fibrous areas with prominent curvilinear vasculature. All tumors were MUC4 positive (100%), 2/4 (50%) were p63 positive, 1/4 (25%) showed focal EMA positivity; all 4 were negative for pancytokeratin, p40, S100 protein, β-catenin, actin, and CD34. LGFMS is a low grade sarcoma that rarely develops in the head and neck. Due to its rarity, a pathologist may not consider LGFMS in the differential diagnosis of spindle cell neoplasms within the head and neck. Immunohistochemical staining is helpful, but stains should be selected carefully to avoid misdiagnosis.

Excellent local control and survival after postoperative or definitive radiation therapy for sarcomas of the head and neck

BACKGROUND

To report our results with postoperative or definitive radiation therapy in head and neck sarcomas.

METHODS

We performed a retrospective analysis of 26 patients suffering from head and neck sarcomas, who received postoperative or definitive radiation therapy between 2003 and 2012. Median age was 64 years (19-88) and 69 % were male. Tumor locations were skull (including skin) in 31 %, paranasal sinus/orbita in 27 % and neck (including pharynx/larynx) in 42 %. Median tumor size was 4.6 cm (1-12 cm). 22 patients (85 %) presented in primary situation. Stage at presentation (UICC 7(th) for soft tissue sarcomas) was as follows: Ia:4 %, IIa:50 %, IIb:15 %, III:31 %. All except one patient suffered from high grade lesions (G2/3 FNCLCC), predominantly angiosarcoma (35 %), MFH (19 %) and synovial sarcoma (15 %). Surgery was performed in 21 pts (81 %), resulting in free margins in 10 (38 %), microscopically positive margins in 6 (23 %) and gross residual disease in 5 (19 %). Median dose to the primary tumor region was 66Gy (45-72Gy) in conventional fractionation, using 3D-CRT in 65 %, IMRT in 27 % and electrons in 8 %. 50 % of the patients also received sequential chemotherapy.

RESULTS

Median follow up was 39 months (8-136). We observed three local recurrences, transferring into estimated 3- and 5-year local control rates of 86 %. One additional patient failed distantly, resulting in 3- and 5-year freedom from treatment failure rates of 82 %. Four patients have deceased, transferring into 3- and 5-year overall survival rates of 88 % and 82 %, respectively. Only two of the four deaths were sarcoma related. Maximum acute toxicity (CTCAE 3.0) was grade 1 in 27 % of the patients, grade 2 in 50 % and grade 3 in 23 %. Severe acute toxicity was mainly represented by mucositis and dysphagia. Maximum late toxicity was grade 1 in 31 %, grade 2 in 15 % and grade 3 in 19 % of the patients. Severe late toxicity included skin ulceration (n = 1), dysphagia with persistent tube dependency (n = 1), persistent sinusitis (n = 1) and hearing loss (n = 2).

CONCLUSION

Excellent local control and overall survival rates can be achieved with postoperative or definitive radiation therapy with acceptable acute and late toxicities in patients suffering from sarcomas of the head and neck region.

Outcomes of the treatment of head and neck sarcomas in a tertiary referral center

Head and neck sarcomas are a rare and heterogeneous group of tumors that pose management challenges. We report our experience with these tumors. Forty consecutive patients treated for 44 head and neck sarcomas between 1997 and 2014 were culled from our prospectively maintained head and neck database. Five patients were excluded. The adult cohort consisted 29 (83%) patients of a mean age of 57.7 years, with 33 sarcomas. The most common diagnoses were undifferentiated pleomorphic sarcoma (27%) and chondroblastic osteosarcoma (21%). Clear surgical margins were achieved in 24/33 (73%) lesions. Twenty-two patients received radiotherapy and/or chemotherapy. Fourteen patients developed local (n = 6), regional (n = 1) and distant (n = 7) recurrence. The overall 5-year survival was 66% with a mean survival interval of 66.5 months. Recurrent sarcoma, close (<1 mm) or involved surgical margins and advanced age were associated with statistically significantly reduced survival. The pediatric cohort consisted 6 (17%) patients, with a mean age of 9 years. Five patients had primary embryonal rhabdomyosarcomas and one had chondroblastic osteosarcoma. Clear surgical margins were achieved in five (83%) patients. All patients received adjuvant radiotherapy and/or chemotherapy. Mean survival interval was 102 months. Three patients developed local (n = 1) or distant (n = 2) recurrence. Twenty-three free and 8 pedicled flaps were performed in 25 patients. Eleven out of thirty-nine (28%) lesions in 11 patients developed a complication. In conclusion, head and neck sarcomas are best managed by a multidisciplinary team at a tertiary head and neck referral center and resection with clear margins is vital for disease control.

Soft tissue sarcoma of the head & neck: nomogram validation and analysis of staging systems

BACKGROUND AND OBJECTIVES

Soft tissue sarcomas of the head and neck (STSHN) comprise a rare group of malignancies. Our objective is to determine the utility of soft tissue sarcoma staging systems within the head and neck, and to validate an individualized soft tissue sarcoma nomogram within head and neck primary sites.

METHODS

Previously-untreated patients with STSHN diagnosed and treated between 1982 and 2012 were eligible (n = 319, median follow-up 46 months). Clinical variables were extracted from a prospectively-maintained database. The performance of AJCC/UICC and MSK staging systems and a soft tissue sarcoma-specific nomogram were assessed.

RESULTS

Four-year overall survival (OS), disease specific survival (DSS), and recurrence-free survival (RFS) were 72%, 76%, and 71%, respectively. AJCC/UICC and MSK staging systems accurately stratified outcomes (OS, DSS, and RFS; P < 0.001 for all comparisons). The nomogram stratified outcomes by quartile (P < 0.001), and predicted risk of death at 4, 8 and 12 years (P < 0.001). Concordance indices for overall survival for the AJCC/UICC system, MSK system, and the nomogram were 0.71, 0.70, and 0.78, respectively.

CONCLUSIONS

Oncologic outcomes among groups of patients with STSHN can be accurately predicted using both the AJCC/UICC and MSK staging systems. A soft tissue sarcoma-specific nomogram provides reliable, individualized prognostic information for patients with STSHN.

Analysis of Clinical Prognostic Factors for Adult Patients with Head and Neck Sarcomas

Objective

To evaluate the treatment, outcome, and prognostic factors in patients with head and neck sarcomas treated in an academic medical center.

Study Design

Case series.

Setting

Academic medical center.

Subjects and Methods

We performed a retrospective analysis of adult patients (n = 97) with primary head and neck sarcomas treated between 2000 and 2012. We analyzed the treatment, outcome, and potential factors predictive of disease-free survival and disease-specific survival. We also evaluated the outcome and prognostic factors in patients with bone and soft tissue sarcomas.

Results

The median overall survival was 6.8 years, with 2-year and 5-year overall survival rates of 78% (95% confidence interval [CI], 66%-86%) and 59% (95% CI, 44%-72%), respectively. Univariable analysis revealed that age at diagnosis (>60 years: hazard ratio [HR], 2.7; 95% CI, 1.2-6.2; P = .01), surgical intervention (HR, 8.3; 95% CI, 3.5-19.5; P < .001), and metastatic disease (HR, 4.3; 95% CI, 1.3-13.6; P = .01) were significantly associated with disease-specific survival.

Conclusion

In this study, patients over the age of 60 years at diagnosis and those with inoperable disease at initial presentation had significantly worse disease-specific survival. Surgical intervention remains the optimal treatment modality for those with resectable disease and was associated with significantly better survival in this heterogeneous series. Further multi-institutional studies are required to better define prognostic factors in individual histological subtypes.

Head and neck sarcomas: analysis of the SEER database

OBJECTIVE

To summarize the epidemiology of sarcomas occurring in the head and neck and identify prognostic factors for patient survival.

STUDY DESIGN AND SETTING

Cross-sectional analysis of the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) program.

METHODS

The SEER 18 registries, comprising sarcoma diagnoses made from 1973 to 2010, were queried for sarcomas arising in the head and neck. Pediatric and adult patients were analyzed separately, and multivariate and propensity-matched analyses were performed to identify predictors of disease-specific survival.

RESULTS

In all, 11,481 adult cases and 1244 pediatric cases were identified. In adults, the most common histologic subtypes were malignant fibrous histiocytoma (MFH), Kaposi sarcoma, and hemangiosarcoma, while in the pediatric cohort, the most common histologic subtypes were rhabdomyosarcoma, MFH, and osteosarcoma. Cause-specific 2-, 5-, and 10-year survival rates were 76%, 66%, and 61% for adults and 84%, 73%, and 71% for pediatric patients. Multivariate analysis performed for adults revealed that male gender, absence of radiation therapy, and stage I disease were associated with improved cause-specific survival reaching statistical significance. However, a propensity-matched model demonstrated no significant difference in cause-specific survival between patients who received radiation and those who did not.

CONCLUSION

Sarcomas, a heterogeneous group of malignant mesenchymal tumors, are uncommonly found in the head and neck. This study represents the largest analysis of patients with head and neck sarcomas in the literature and demonstrates the impact of age, gender, primary site, histology, and radiation status on overall prognosis.

Head and neck sarcomas: the UCLA experience

PURPOSE

To profile the clinical presentation, subtype distribution, and treatment results of sarcomas of the head and neck at a single tertiary academic center over an 11-year period.

MATERIALS AND METHODS

A retrospective review was performed by examining the records and reviewing the pathology of 186 patients with head and neck sarcomas treated at UCLA Medical Center from 2000 to 2011.

RESULTS

The mean age of the study population was 49 ± 22 years. 58% of the patients were male and 42% were female. Median duration of follow-up for the entire group was 18.5 months. The most common presenting symptom was a mass lesion in 59.9% of patients. The nasal cavity/sinus was the most common presenting site seen in 22% of patients. Solitary fibrous tumor/hemangiopericytoma was the most common subtype. 15% of patients had evidence of prior radiation exposure. 26.3% of tumors were greater than 5 cm and 35.5% were high-grade. Margins were positive in 31.2% of patients. Lymph node metastasis was rare at 6.5%. Perineural invasion was identified in 6.5%. Among all subtypes, 5-year recurrence-free survival and overall survival were 50% and 49%, respectively. Multivariate analysis demonstrated that grade and margin status were predictors of recurrence-free survival while grade and age affected overall survival.

CONCLUSIONS

Head and neck sarcomas are a rare entity frequently presenting as a mass lesion. In our series, lesions tended to be high-grade with a significant portion of surgical specimens having positive margins. Grade and margin status were the most important predictors of survival.

Surgical management of giant secondary malignant fibrous histiocytoma following radiotherapy for nasopharyngeal carcinoma: A case report and literature review

Malignant fibrous histiocytoma (MFH) is rare in the chest wall, particularly in patients who have undergone radiotherapy for primary nasopharyngeal cancer. In the present study, a case of MFH of the upper chest wall that appeared four years after initial radiotherapy for squamous cell carcinoma of the nasopharynx is reported. Furthermore, two-step surgical management was successfully performed consisting of i) tumor-reductive excision and ii) limb salvage surgery, including wide resection of the tumor mass, defect reconstruction of the chest wall using left latissimus dorsi myocutaneous flap and dermatoplasty of the flap-supplied region. The progress of the clinical characteristics, the reasons for radiation-induced carcinogenesis, the treatment options and the prognostic factors of MFH are also reviewed. Finally, the importance of prevention and follow-up of this malignancy are highlighted and specific advice is offered.

Radiation-induced malignant fibrous histiocytoma of the occipital: a case report

Malignant fibrous histiocytoma (MFH) is a rare neoplasm exhibiting a propensity for aggressive clinical behavior. Effective treatment modality is surgical resection with wide margins, but its rate of recurrence and metastasis is still high. Early detection and complete excision of the tumor is necessary. A MFH of the occipital developed in a 51-year-old woman eight years after surgery and radiation for medulloblastoma of the cerebellar vermis. The secondary neoplasm arose at the site of tumor resection within the irradiated field, and was resected. The development of sarcomas is a recognized complication of radiation therapy. The final diagnosis after the operation was MFH. Radiation-induced sarcoma (RIS) is well known, but radiation-induced MFH is relatively rare in the head and neck region, especially in the occipital. The imaging findings are not diagnosis specific, but strict follow-up within the radiation field by computerized tomography (CT) and magnetic resonance imaging (MRI) and appreciation of the expected latency period may help in providing the diagnosis of RIS.