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Objective Current transnasal endoscopic techniques for sinus and skull base surgery use a single endoscope to provide visualization from one perspective curtailing depth perception and compromising visualization of the instrument–target interface. The view can be blocked by instruments, and collisions between instruments often occur. The objective of this study was to investigate the use of multiportal retrograde endoscopy to provide more accurate manipulation of the surgical target. Design Maxillary antrostomy and frontal sinusotomy were performed on three different cadavers by three different surgeons. A zero-degree rigid endoscope was introduced through the nose for the standard transnasal approach. A flexible endoscope was introduced transorally, directed past the palate superiorly, and then flexed 180 degrees for the retrograde view. Videos of the standard transnasal view from the rigid endoscope and retrograde view from the flexible endoscope were recorded simultaneously. Results All surgeries were able to be performed with dual-screen viewing of the standard and retrograde view. The surgeons noted that they utilized the retrograde view to adjust the location of ends/tips of their instruments. Four surgeons reviewed the videos and individually agreed that the visualization achieved provided a perspective otherwise not attainable with rigid transnasal endoscopy alone. Conclusion High-quality visualization of surgical targets such as the frontal or maxillary ostia can be challenging with rigid endoscopes alone. Multiportal retrograde endoscopy provides proof of concept that additional views of a surgical target can be achieved. Additional work is needed to further develop indications, techniques, and generalizability to targets beyond those investigated here.

Objective Several different open and endoscopic approaches for the pterygomaxillary space and infratemporal fossa have been described. Limitations to these approaches include restricted exposure of the infratemporal fossa and difficult surgical manipulation. Study Design Consecutive clinical cases utilizing a novel approach to access lesions in the infratemporal fossa and pterygomaxillary space were reviewed. Data was collected on pathology, lesion location, and surgical approach(es) performed. Computer modeling was performed to analyze the full extent of surgical access provided by the paramaxillary approach to the range of target locations. Results Ten consecutive cases met inclusion criteria. Surgical access to the target lesion was achieved in all cases. Computer modeling of the approach derived the anatomical boundaries of the paramaxillary approach. Wide access to the posterior maxilla, and lateral or medial to the mandibular condyle allows for variability in endoscopic angles and access to more medial pterygomaxillary space lesions. The lateral extent is limited proximally only by the extent of cheek/soft tissue retraction and by the zygomatic arch more superiorly. The superior limit of dissection is at the temporal line. Conclusion The endoscopic paramaxillary approach is a transoral minimally disruptive approach to the ITF and PS that provides excellent surgical exposure for resection of lesions involving these areas. Compared with previously described endoscopic approaches, there are no external incisions; tumor manipulation is straightforward without angled endoscopy, and all areas of the infratemporal fossa and pterygomaxillary space can be accessed.

Robotic surgery has been shown to be feasible and successful in several areas of pediatric head and neck surgery. However, adoption has been limited. Robotic surgery may be better integrated into practice with advanced preoperative surgical planning and the design of new robotic platforms with instrumentation specific for the application. With continued investigations, computer-aided surgical planning techniques including three-dimensional printing, virtual reality, multiobjective cost function for optimization of approach, mirror image overlay, and flexible robotic instruments may demonstrate value and utility over current practice.

Introduction Many theories on the pathophysiology of chronic rhinosinusitis with nasal polyposis (CRSwNP) exist. The most effective management of CRSwNP has not been elucidated. Doxycycline, which has anti-inflammatory and anti-bacterial properties, has shown durable effects; however, its efficacy in combination with standard therapy has not been examined. We hypothesized that its addition to the standard anti-inflammatory regimen would improve patient outcomes. Methods We performed a double-blind, placebo-controlled trial at a tertiary level institution. Patients with moderate or severe CRSwNP were randomized into two groups, each receiving a 20-day course of oral corticosteroids and doxycycline or placebo. The 22-item Sinonasal Outcome Test (SNOT-22), nasal polyp scores, and visual analog scale (VAS) scores were recorded at the initial, 3-, 8- and 12-week visits. Results 49 patients were enrolled, 24 in the experimental and 25 in the placebo group with 3 moderate disease patients in each group. There were 12 dropouts in the treatment group and 14 in the placebo group. The most common reasons for dropout were severe CRS and asthma exacerbations. There was no significant difference in SNOT-22 scores, nasal polyp scores, and VAS scores between the two arms. Conclusions Non-surgical management of patients with CRSwNP remains challenging. Our conclusions are limited given the high dropout rate and thus, limited sample size with inadequate power. This study is important, however, because a high dropout rate of mostly severe disease patients may illustrate that this patient population may not be optimally managed with medical therapy alone.

The initial management of atypical meningiomas poses a distinct clinical challenge in that treatment protocols have not been fully established, and outcomes, especially differences by patient age, have not been broadly measured. The National Cancer Database (NCDB) allows for analysis of a large, diverse patient population to determine clinical parameters and survival outcomes based on the initial treatment of patients with atypical meningiomas.Analysis of the NCDB yielded 3611 atypical meningioma patients treated between 2008 and 2012. Principal treatment paradigms included surgery with or without radiation. Survival estimates were calculated using Kaplan-Meier curves stratified by age at diagnosis for each treatment paradigm. Subset analysis was performed for socio-economic factors.Overall 5-year survival rate was 77.6% and declined with increasing patient age (p 0.0001). Five-year survival for patients ≤ 45 years undergoing surgery alone was 89.3 vs. 44.4% for those 75 years (p 0.0001). For patients undergoing surgery with adjuvant radiation, 5-year survival was 93.7% in those ≤ 45 years and 54.1% in those 75 years (p 0.0001). Use of adjuvant radiation was stable over time. Private-insured patients were more likely to receive adjuvant radiation (p = 0.0001).Patients treated for atypical meningioma have high rates of 5-year survival. A marginal survival benefit of adjuvant radiation was observed for patients 55 and 75 years, while patients between 55 and 75 years tended to have slightly improved survival with surgery alone. Though surgery remains the standard of care in the primary treatment of atypical meningioma, the decision to administer radiation post-operatively has remained controversial.

OBJECTIVES/HYPOTHESIS Patients who present to the emergency department (ED) with various otolaryngologic disorders are frequently referred to an otolaryngologist for follow-up care. Our aim was to further characterize this group as it has not been well described in the literature. STUDY DESIGN Cross-sectional retrospective study. METHODS We reviewed the charts of patients seen during an 18-month period in an urban public hospital trauma center adult ED and referred to an otolaryngology clinic for follow-up care. RESULTS Seven hundred thirty-eight patients were seen and referred; the most common diagnoses made by ED providers were peripheral vertigo (12%), otitis externa (8%), and nasal fractures (8%). Nine percent of patients were evaluated during their ED visit by an otolaryngology provider. Three hundred seventy-two (50%) patients returned for their otolaryngology clinic visit; facial trauma patients were least likely to return. The most common diagnoses made by otolaryngology providers were otitis externa (12%), peripheral vertigo (12%), and nasal fractures (7%). There was 50% concordance between patients' diagnoses made by ED and otolaryngology providers. The most common differences were otitis media versus otitis externa (10%) and acute pharyngitis versus laryngopharyngeal reflux (8%). During 37% of follow-up visits, an in-office procedure was performed, most commonly flexible fiberoptic laryngoscopy, cerumen removal, and nasal endoscopy. CONCLUSIONS Our analysis reports comprehensive characteristics of this referral group, identifying potential areas for improvement in patient management, resident education and efficiency. Otolaryngologists covering EDs should be familiar with this population in terms of types of cases that may affect their practices. LEVEL OF EVIDENCE 4. Laryngoscope, 128:1062-1067, 2018.

Objective To determine if pharyngeal packs have an effect on postoperative pain and postoperative nausea and vomiting in functional endoscopic sinus surgery (FESS). Study Design Forty-six patients scheduled for routine endoscopic sinus surgery were recruited into this study. The patients were randomly allocated to have or to not have pharyngeal packing prior to surgery. Methods The placement of pharyngeal packs during FESS is controversial. Theoretically, pharyngeal packs may prevent postoperative nausea and vomiting by preventing ingestion of blood during sinus surgery. However, prior studies have not conclusively demonstrated this to be the case in FESS. Pharyngeal packs have been associated with complications including throat pain, aspiration, and death. The objective of this randomized control trial was to determine if pharyngeal packs have an effect on postoperative throat pain, nausea, and vomiting in order to determine their importance during FESS. Patients were blinded to intervention. Postoperatively, throat pain and nausea/vomiting scores were recorded. Results There was no significant difference in mean throat pain at 4 hours following surgery (P = 0.860). At 24 hours after surgery, patients without pharyngeal packing experienced more pain than those who had a throat pack placed (P = 0.002). There was no significant difference in the level of nausea at 4 hours after surgery (P = 0.315) or at 24 hours after surgery (P = 0.315). Conclusion We recommend against the routine use of placing pharyngeal packs during FESS. Level of Evidence 1b. Laryngoscope, 127:2460–2465, 2017

Objective To describe patient demographics, histology, treatment modalities, and survival associated with adult sinonasal rhabdomyosarcoma. Study Design Retrospective review of a national database. Setting Tertiary medical center. Subjects and Methods Patient demographics, tumor histology, treatment modalities, and survival trends were examined for patients aged ≥18 years who were diagnosed with sinonasal rhabdomyosarcoma between 2004 and 2013 with the National Cancer Database. Kaplan-Meier analysis and the log-rank tests were performed to determine the unadjusted association between overall survival and various patient and disease characteristics. Results A total of 186 patients were identified; 5-year overall survival was 28.4%. Over half of patients were between 18 and 35 years old at diagnosis (53.8%), which was associated with improved 5-year overall survival over patients >35 years old (31.9% vs 24.4%, P = .014). Alveolar sinonasal rhabdomyosarcoma was most common (66.7%). There was no statistical difference in 5-year overall survival between alveolar and embryonal subtypes (30.5% vs 41.6%, P > .05). Metastatic disease was present in 27.7% of patients and was associated with worse 5-year overall survival (14.7% vs 33.9%, P < .0001). The majority of patients were treated with chemotherapy with adjuvant radiation (49.5%). A quarter of patients were treated with surgery plus chemoradiation (25.8%). Conclusion We present the largest analysis of adult sinonasal rhabdomyosarcoma using a standardized national based database. Adult sinonasal rhabdomyosarcoma has a very poor prognosis independent of histologic subtype. The small number of surgical cases limits the ability of the analysis to accurately compare treatment with chemoradiation with and without surgery.

Background Sinonasal undifferentiated carcinoma (SNUC) is a rare, aggressive malignancy of unknown etiology with a poor overall prognosis. Its relative rarity has made it difficult to determine the impact of different treatment modalities on survival. Methods Retrospective study of cases in the National Cancer Data Base (NCDB). NCDB cases that were diagnosed as having SNUC between January 1, 2004, and December 31, 2013 were included in the analysis. Outcomes of patients treated with surgery followed adjuvant chemoradiotherapy were compared with definitive chemoradiotherapy. Results A 5-year survival rate of 42.2% was observed in the 460 patients in the analysis. American Joint Committee on Cancer (AJCC) clinical staging data were available for 304 patients. Of these patients, 60.2% had advanced tumors (AJCC stage 3 or 4). Surgery followed by adjuvant chemoradiotherapy was associated with better survival than definitive chemoradiotherapy (55.8% vs 42.6%, p = 0.007) in the study population. However, in late-stage tumors, there was no difference in survival between the 2 treatment groups (p = 0.22). For late-stage tumors, the time to initiation of adjuvant therapy was 49.2 ± 5.1 days for the surgery plus adjuvant therapy group as compared with 25.9 ± 2.6 days in the definitive chemoradiotherapy group (p 0.05). Margin status played a critical role in the success of surgical resection, as no patients with positive margin status receiving adjuvant therapy survived to 5 years. Conclusion Surgery may play a role in a multimodality approach to treatment of late-stage SNUC if the tumor is amenable to surgical resection and negative margins can be reliably obtained. However, in cases where there may be difficulty obtaining negative margins, or this is considered unlikely preoperatively, surgical resection does not appear to provide any additional survival benefit.

Background Most data on sinonasal mucosal melanoma come from small institutional studies, and therefore optimal treatment methods are not well understood. The purpose of this study was to analyze the association between treatment and survival in sinonasal mucosal melanoma. Methods Six hundred ninety–five patients diagnosed with sinonasal mucosal melanoma between 2004 and 2010 were identified from the National Cancer Data Base. Treatment modalities and overall survival rates were determined. Results The 5–year overall survival was 21.7%, with a mean survival of 38.4 ± 1.7 months. The majority of patients were treated with surgery alone (31.5%) or surgery with adjuvant radiotherapy (41.4%). There was no statistical difference between survival with surgery alone and surgery with adjuvant radiation therapy (25.1% vs 25.1%, p = 0.93). Between the surgery and surgery–with–adjuvant–therapy groups, there was no difference in the number of patients with positive margins (p = 0.54), regional lymph node metastases at diagnosis (p = 0.55), morbidity scores (p = 0.58), insurance status (p = 0.13), age > 60 years (p = 0.24), or treatment at academic centers (p = 0.12). Conclusions Based on this large review of patients with sinonasal mucosal melanoma, adjuvant radiation therapy may not provide a survival benefit as patients tended to do poorly regardless of adjuvant radiation status.

BackgroundSecondary cerebrospinal leaks (CSF) are leaks that recur after an initial endoscopic repair of CSF leaks. Identification of characteristics that could predict secondary leaks may allow surgeons to plan repairs with the knowledge that these defects are more likely to fail.ObjectiveTo identify characteristics that could predict secondary CSF leaks.MethodsA search of all studies that reported outcomes after endoscopic repair of CSF leaks was conducted by using medical literature data bases. Studies with the following criteria were included: written in the English language, secondary CSF leaks after primary repair, and assessment of success of fistula repair. Data extracted included the etiology of the leak, site of the leak, reconstructive materials used, and success of the repair.ResultsNinety-four studies, from 1988 to 2015, with a total of 3149 primary CSF leaks were included. Sixty-three studies (67%) had a success rate of ≥80%; 77 studies (82%) had secondary leak rates of ConclusionThe rate of secondary CSF leaks was low due to advances in endoscopic repair techniques. Spontaneous and iatrogenic CSF leaks were more likely to recur, especially without adequate control of underlying factors, such as increased intracranial pressure and obesity. Further studies with consistent reporting are required for more definitive conclusions about secondary CSF leaks.

Mammals express thousands of long noncoding (lnc) RNAs, a few of which are known to function in tissue development. However, the entire repertoire of lncRNAs in most tissues and species is not defined. Indeed, most lncRNAs are not conserved, raising questions about function. We used RNA sequencing to identify 1109 polyadenylated lncRNAs expressed in erythroblasts, megakaryocytes, and megakaryocyte-erythroid precursors of mice, and 594 in erythroblasts of humans. More than half of these lncRNAs were unannotated, emphasizing the opportunity for new discovery through studies of specialized cell types. Analysis of the mouse erythro-megakaryocytic polyadenylated lncRNA transcriptome indicates that ~75% arise from promoters and 25% from enhancers, many of which are regulated by key transcription factors including GATA1 and TAL1. Erythroid lncRNA expression is largely conserved among 8 different mouse strains, yet only 15% of mouse lncRNAs are expressed in humans and vice versa, reflecting dramatic species-specificity. RNA interference assays of 21 abundant erythroid-specific murine lncRNAs in primary mouse erythroid precursors identified 7 whose knockdown inhibited terminal erythroid maturation. At least 6 of these 7 functional lncRNAs have no detectable expression in human erythroblasts, suggesting that lack of conservation between mammalian species does not predict lack of function.

To determine if pharyngeal packs have an effect on postoperative pain and postoperative nausea and vomiting in functional endoscopic sinus surgery (FESS).Forty-six patients scheduled for routine endoscopic sinus surgery were recruited into this study. The patients were randomly allocated to have or to not have pharyngeal packing prior to surgery.The placement of pharyngeal packs during FESS is controversial. Theoretically, pharyngeal packs may prevent postoperative nausea and vomiting by preventing ingestion of blood during sinus surgery. However, prior studies have not conclusively demonstrated this to be the case in FESS. Pharyngeal packs have been associated with complications including throat pain, aspiration, and death. The objective of this randomized control trial was to determine if pharyngeal packs have an effect on postoperative throat pain, nausea, and vomiting in order to determine their importance during FESS. Patients were blinded to intervention. Postoperatively, throat pain and nausea/vomiting scores were recorded.There was no significant difference in mean throat pain at 4 hours following surgery (P = 0.860). At 24 hours after surgery, patients without pharyngeal packing experienced more pain than those who had a throat pack placed (P = 0.002). There was no significant difference in the level of nausea at 4 hours after surgery (P = 0.315) or at 24 hours after surgery (P = 0.315).We recommend against the routine use of placing pharyngeal packs during FESS.1b. Laryngoscope, 127:2460-2465, 2017.

Objective: Sphenoid sinus mucocele is a rare complication of transsphenoidal surgery and can present clinically many years after the initial surgery. Although the formation of sphenoid sinus mucocele has been previously described in the literature as case reports, there is no information demonstrating the incidence of sphenoid sinus mucocele after sphenoid obliteration in a large series. This study aims to determine the incidence of sphenoid sinus mucocele formation and other postoperative complications following transsphenoidal surgery with fat obliteration. Methods: A retrospective review was performed of patients who underwent sphenoid obliteration with fat after Transsphenoidal approach for pituitary adenoma by two surgeons at our institution from 2001 to 2003. Follow-up records up to 2015 were obtained for these patients. Data collected included demographics, operation performed, sphenoid sinus obliteration method, reconstruction method, follow-up period, postoperative complications, recurrence and residual disease. Results: Of the 95 patients who underwent Transsphenoidal approach and sphenoid obliteration with fat, 27 patients developed postoperative complications. None had sphenoid sinus mucocele formation. Recurrence of disease occurred in 11.6% of patients. Residual disease was present in 7.4% of patients. Complications included sinusitis, hematoma, hyponatremia, acromegaly and postoperative need for the placement of a ventriculoperitoneal shunt. Conclusion: Sphenoid sinus mucocele formation is a rare complication following transsphenoidal surgery with fat obliteration with an estimated incidence of less than 1.1%. Further studies with more cases are needed to accurately establish the incidence.

Background Given the rarity of esthesioneuroblastoma, it is difficult to validate a staging system. The purpose of this study was to investigate the utility of the Kadish staging system in esthesioneuroblastoma using the National Cancer Database (NCDB). Methods One thousand one hundred sixty-seven patients with esthesioneuroblastoma were identified from the NCDB. Results Five-year survival was 80.0% for Kadish A, 87.7% for Kadish B, 77.0% for Kadish C, and 49.5% for Kadish D. Kadish B had higher survival than Kadish A. More Kadish B patients received surgery with adjuvant therapy than Kadish A patients (41.6% vs 32.5%; P = .0038) and also had more positive margins (21.6% vs 11.3%; P = .03). There was no difference in age distribution, sex, race, or neck dissection status between the 2 groups. Conclusion Kadish B had greater survival than Kadish A, but the treatment characteristics could not account for this difference. The utility of early-stage Kadish staging is uncertain and requires further study.

Sinonasal undifferentiated carcinoma (SNUC) is a rare, aggressive malignancy of unknown etiology with a poor overall prognosis. Its relative rarity has made it difficult to determine the impact of different treatment modalities on survival.Retrospective study of cases in the National Cancer Data Base (NCDB). NCDB cases that were diagnosed as having SNUC between January 1, 2004, and December 31, 2013 were included in the analysis. Outcomes of patients treated with surgery followed adjuvant chemoradiotherapy were compared with definitive chemoradiotherapy.A 5-year survival rate of 42.2% was observed in the 460 patients in the analysis. American Joint Committee on Cancer (AJCC) clinical staging data were available for 304 patients. Of these patients, 60.2% had advanced tumors (AJCC stage 3 or 4). Surgery followed by adjuvant chemoradiotherapy was associated with better survival than definitive chemoradiotherapy (55.8% vs 42.6%, p = 0.007) in the study population. However, in late-stage tumors, there was no difference in survival between the 2 treatment groups (p = 0.22). For late-stage tumors, the time to initiation of adjuvant therapy was 49.2 ± 5.1 days for the surgery plus adjuvant therapy group as compared with 25.9 ± 2.6 days in the definitive chemoradiotherapy group (p0.0001), yet this did not appear to affect outcomes. No differences in age, gender, race, Charlson-Deyo score, facility type (academic vs nonacademic), or radiation dose were found between the 2 treatment groups (p0.05). Margin status played a critical role in the success of surgical resection, as no patients with positive margin status receiving adjuvant therapy survived to 5 years.Surgery may play a role in a multimodality approach to treatment of late-stage SNUC if the tumor is amenable to surgical resection and negative margins can be reliably obtained. However, in cases where there may be difficulty obtaining negative margins, or this is considered unlikely preoperatively, surgical resection does not appear to provide any additional survival benefit.

Most data on sinonasal mucosal melanoma come from small institutional studies, and therefore optimal treatment methods are not well understood. The purpose of this study was to analyze the association between treatment and survival in sinonasal mucosal melanoma.Six hundred ninety-five patients diagnosed with sinonasal mucosal melanoma between 2004 and 2010 were identified from the National Cancer Data Base. Treatment modalities and overall survival rates were determined.The 5-year overall survival was 21.7%, with a mean survival of 38.4 ± 1.7 months. The majority of patients were treated with surgery alone (31.5%) or surgery with adjuvant radiotherapy (41.4%). There was no statistical difference between survival with surgery alone and surgery with adjuvant radiation therapy (25.1% vs 25.1%, p = 0.93). Between the surgery and surgery-with-adjuvant-therapy groups, there was no difference in the number of patients with positive margins (p = 0.54), regional lymph node metastases at diagnosis (p = 0.55), morbidity scores (p = 0.58), insurance status (p = 0.13), age60 years (p = 0.24), or treatment at academic centers (p = 0.12).Based on this large review of patients with sinonasal mucosal melanoma, adjuvant radiation therapy may not provide a survival benefit as patients tended to do poorly regardless of adjuvant radiation status.

Mammalian genomes encode thousands of long noncoding (lnc) RNAs, although the extent to which lncRNAs regulate biological functions is not known. Indeed, most lncRNAs show low levels of conservation among mammals, which could suggest limited or species-restricted functions. We used RNA-seq to identify 683 and 1189 lncRNAs expressed during mouse and human erythropoiesis respectively, of which ∼25% are erythroid-specific. Primary cell chromatin immunoprecipitation (ChIP) studies indicate that most mouse erythroid lncRNAs arise from classical promoters, and their genomic loci are bound by the hematopoietic transcription factors GATA1 and SCL/TAL1. Using the G1E-ER4 cell line, which has an inducible form of GATA1, we found that lncRNAs whose genomic loci are bound by GATA1 in primary cells are upregulated on GATA1 induction in the cell line, similar to coding genes. We compared RNA-Seq transcriptomes of erythroblasts from 8 different mice strains and showed that lncRNA expression is highly conserved within strains of the same species. A comparison of the human and mouse lncRNA transcriptomes showed that only 15% of mouse erythroblast lncRNAs have detectable syntenic transcripts in human erythroblasts, and that most lncRNAs are not detectable in humans. To identify functional lncRNAs, we used RNA interference in primary erythroblasts to analyze the functions of 21 abundantly expressed murine erythroid lncRNAs, 15 of which are mouse specific and 6 of which have orthologous transcripts in humans. Suppression of seven different lncRNAs inhibited various aspects of erythroid maturation including loss of cell volume, down-regulation of the surface marker CD44, and enucleation. The suppression of enucleation ranged from 25% reduction to 75% reduction of enucleation demonstrated with at least 2 separate shRNAs for each of the 7 lncRNAs (p Disclosures: No relevant conflicts of interest to declare.

Abstract 2331 Lnc (long noncoding) RNAs are RNA transcripts greater than 200nt that regulate gene expression independent of protein coding potential. It is estimated that thousands of lncRNAs play vital roles in diverse cellular processes and are involved in numerous diseases, including cancer. We hypothesize that multiple lncRNAs regulate erythrocyte and megakaryocyte formation by modulating gene expression. To identify lncRNAs in erythro-megakaryopoiesis, we purified two biological replicates each of murine Ter119+ erythroblasts, CD41+ megakaryocytes and bipotential megakaryocyte-erythroid progenitors (MEPs) [Lin− Kit+, Sca1−, CD16/32−, CD34−]. We performed strand-specific, paired-end, 200nt-read-length deep sequencing (RNA-Seq) to a depth of ∼200 million reads per sample using the Illumina GAII platform. We used the Tophat and Cufflinks suite of bioinformatic tools to assemble and compare de-novo transcriptomes from these three cell types, producing a high-confidence set of 69,488 transcripts. We confirmed that the RNA-seq assemblies accurately reflect gene expression predicted from prior studies. For example, Ter119+ cells were highly enriched for key erythroid transcripts encoding globins, heme synthetic enzymes and specialized membrane proteins. Megakaryocytes expressed high levels of gene encoding lineage-specific integrins and platelet markers. MEPs expressed numerous progenitor genes including Gata2, Kit and Myc. Thus, the RNA-seq data are of high-quality and sufficient complexity to accurately represent erythroid, megakaryocytic and MEP transcriptomes. We used a series of Unix-based bioinformatic filtering tools to identify lncRNAs that are expressed in these transcriptomes. We identified 605 “stringent” lncRNAs, and 813 “potential noncoding” transcripts. 47% of the lncRNAs are novel unannotated transcripts, validating the use of de-novo RNA-Seq in unique cell populations for lncRNA discovery. Among the 605 “stringent” lncRNAs, 103 are erythroid-restricted, 133 are meg-restricted and 280 are MEP-restricted, consistent with reports that lncRNAs exhibit exquisitely cell-type specific expression. Current efforts are aimed at generating a more comprehensive map of lncRNA expression at specific stages of erythroid and megakaryocyte/platelet development, and performing high throughput functional screens to analyze currently identified lncRNAs. Our studies are beginning to define new layers of gene regulation in normal erythro-megakaryopoiesis and are relevant to the pathophysiology of related disorders including various anemias, myeloproliferative and myelodysplastic syndromes and leukemias. Disclosures: No relevant conflicts of interest to declare.