Incidental finding of thyroglossal duct cyst in a neonate during endotracheal intubation: a case report.

BACKGROUND: Thyroglossal Duct Cyst (TDC) is a common lesion of the midline neck, originating from an incomplete involution of the thyroglossal duct. It is typically observed in pre-scholar patients and surgery is the treatment of choice to prevent infections. Here reported a case of incidental diagnosis in a newborn patient. CASE PRESENTATION: a 3-week-old male baby was admitted to our hospital for weight loss and projectile vomits after breastfeeding. After a diagnosis of hypertrophic pyloric stenosis, the baby underwent pyloromyotomy. During the endotracheal tube placement, the anesthetist noticed the presence of a midline neck mass. The suspect of TDC was confirmed by an intraoperative ultrasound, so, despite the age of the patient, we proceeded with the excision of the lesion according to Sistrunk's procedure to avoid future complications and anesthesia. CONCLUSIONS: even if TDC is a common lesion of pediatric patients, anecdotical neonatal cases were described in the literature, all of them symptomatic. An accurate physical examination and ultrasound are essential diagnostic tools to distinguish TDC from other middle neck lesions, particularly ectopic thyroidal tissue. Sistrunk's procedure is the most effective surgical approach. When diagnosis is made in a newborn, we suggest postponing surgery, unless the baby requires general anesthesia for other surgical procedures, such as in our case.

Clinical Characteristics and Prognosis of Infants and Children <3 Years of Age With Thyroglossal Duct Cyst Complicated With a Parapharyngeal Mass: A Case Series Study.

Thyroglossal duct cysts (TGDCs) are congenital and developmental abnormalities in infants and young children. This retrospective case series study examined the characteristics of 7 patients <3 years (mean age, 1.9 years) with TGDC complicated with a parapharyngeal mass treated at one hospital between January 2019 and 2022. Four patients had a painless mass around the neck, 2 had a painless mass associated with snoring, and 1 presented repeated swelling and pain. B-ultrasound suggested 6 cases of TGDC and 1 possible lymphangioma. All patients were treated with Sistrunk surgery to remove the TGDC. Six patients had no cyst recurrence during follow-up (6 months to 2 years). In conclusion, TGDC complicated with a parapharyngeal mass has complex and variable clinical manifestations. Completely removing the cyst while sparing thyroid cartilage and surrounding vascular and neuroanatomical structures is important to avoid complications. The patients are likely to be free from recurrence after surgery.

Papillary Thyroid Cancer in Thyroglossal Duct Cysts: A Pictorial Review and Case Series.

ABSTRACT: Thyroglossal duct cyst is the most common congenital neck mass, but the incidence of malignancy within a thyroglossal duct cyst is rare, estimated at 1%. Most cancers arising within thyroglossal duct cysts are incidentally detected after surgical excision. We present the preoperative radiologic findings of 8 patients with papillary thyroid cancer arising within a thyroglossal duct cyst, as evaluated on ultrasound, computed tomography, magnetic resonance imaging, and positron emission tomography scan.

Diagnosis and Treatment of Double Thyroglossal Duct Cyst.

This retrospective study aimed to investigate clinical diagnostic and management characteristics of double thyroglossal duct cyst (TDC) cases. Seventy-eight patients diagnosed with TDCs who were admitted to the inpatient ward of the Department of Otolaryngology, Dalian Central Municipal Hospital from June 2008 to October 2021 were included in the study. Ultimately, 67 of these patients were diagnosed with single TDCs and 11 patients with double TDCs. Each patient underwent computed tomography and color doppler ultrasound imaging of their neck masses, thyroid color doppler ultrasound imaging, and surgical cyst removal through the classic Sistrunk procedure. All surgically excised specimens were sent to the pathology lab for examination and were confirmed to contain TDCs. Two of the 67 patients with single TDCs experienced postoperative complications related to infections within the operative area, whereas no patients with double TDCs experienced postoperative infection, excessive bleeding, or other surgical complications. All cases were followed up for 1 to 3 years after surgery with no cyst recurrence observed. Double TDCs may present on physical examination as unilateral neck masses that interfere with tongue extension and movement and swallowing that can be identified using imaging methods. Correct clinical diagnosis and complete surgical removal of cysts are key measures for ensuring successful treatment outcomes for patients with TDCs.

Thyroglossal duct cyst carcinoma case series-Management strategy and outcomes / Serie de casos de carcinoma del conducto tirogloso: estrategias de tratamiento y resultados

Objective: To review the clinical presentation, diagnosis, pathology and management strategies in a modern cohort of patients with thyroglossal duct cyst carcinoma. Study design: Retrospective case series following PROCESS Guidelines. Setting Comprehensive cancer centre. Methods: Data recorded included: gender, age at diagnosis, clinical presentation, thyroid function, diagnostic investigations, cytological results, final histology, staging and follow up status. The risk of malignancy in cytological analysis was stratified according to the Royal College of Pathologists classification in United Kingdom. Results: Twelve patients were included. The majority of patients (66.7%) presented with an isolated thyroglossal duct cyst. Only 4 patients had preoperative cytological suspicion of carcinoma (sensitivity: 33.3%). At the time of presentation all patients were euthyroid. Following diagnosis of malignancy, a total thyroidectomy was performed in all patients, with the exception of 2, who had a thyroglossal duct cyst carcinoma of less than 10mm. Among the 10 patients who underwent total thyroidectomy, 7 (70%) patients had proven carcinoma in the thyroid gland, 3 with deposits of less than 10mm. The average size of the thyroid cancer deposits was 7.2mm (1–20mm). With a mean follow-up of is 44 months (5–120), all patients were alive and free of recurrence at the end of the study period. Conclusion: Thyroglossal duct cyst carcinoma is a rare condition and its management should be discussed in a multidisciplinary meeting. As with differentiated thyroid cancer originating in the thyroid gland, it bears extraordinary survival rates. Accordingly, the management of these cancers has shifted towards a more conservative approach although its peculiarities must be taken into account: ease of extracystic invasion and possible different lymph node invasion. (AU)

Objetivo: Revisar la presentación clínica, el diagnostico, la histología y las estrategias de tratamiento en una cohorte moderna de pacientes con carcinoma del conducto tirogloso. Diseño del estudio: Serie de casos retrospectiva utilizando PROCESS Guidelines. Localización: Unidad de cáncer de cabeza y cuello. Métodos: Los datos incluidos fueron: sexo, edad al diagnóstico, presentación clínica, función tiroidea, investigaciones diagnósticas, resultados citológicos, histología final, estadificación y estado durante el seguimiento. El riesgo de malignidad en el análisis citológico fue estratificado de acuerdo con la clasificación del Royal College of Pathologists del Reino Unido. Resultados: Se incluyeron 12 pacientes. La mayoría de ellos (66,7%) presentaron solamente un quiste del conducto tirogloso al diagnóstico. Solamente 4 pacientes tuvieron sospecha de malignidad de acuerdo con los resultados de la citología preoperatoria. En el momento de la presentación, todos los pacientes tenían función tiroidea normal. Después del diagnóstico, se realizó tiroidectomía total a todos los pacientes menos dos, que tuvieron carcinoma del conducto tirogloso menor de 10mm. Entre los 10 pacientes que recibieron tiroidectomía total, 7 (70%) sufrieron carcinoma en la glándula tiroides, 3 de ellos con depósitos menores de 10mm. El tamaño medio de los depósitos de carcinoma en la glándula tiroides fue de 7,2mm (1-20mm). Con una media de seguimiento de 44meses (5-120), todos los pacientes estaban vivos y libres de recidiva al final del periodo estudiado. Conclusión: El carcinoma del conducto tirogloso es una entidad poco frecuente y su manejo debe ser realizado por un equipo multidisciplinario. Igual que en el carcinoma diferenciado de tiroides que se origina en la glándula tiroides, las tasas de supervivencia son excelentes. ... (AU)

Diagnostic accuracy of ultrasonography to distinguish thyroglossal duct cysts from dermoid cysts in children with a midline neck swelling.

INTRODUCTION: Midline neck swellings are very common in children and mostly caused by thyroglossal duct cysts (TGDCs) or dermoid cysts (DCs). Since DCs can undergo simple excision, whilst TGDCs demand more thorough resection via Sistrunk procedure, it is important to differentiate between both pre-operatively. Previous studies have suggested an ultrasound-score (SIST) based on presence of septae, wall irregularity and solid components could do so. This study aims to evaluate the diagnostic accuracy of this score. METHODS: All patients (≤18 years) undergoing surgery between 2006 and 2018 for a midline neck mass at our tertiary centre with a histopathological diagnosis of TGDC or DC were retrospectively included. The pre-operative ultrasound was evaluated by an experienced radiologist and the SIST as well as location, tract, echogenicity, margin and multilocularity were scored. RESULTS: We included 97 children, of whom 67 (69 %) with TGDCs. The SIST showed a sensitivity of 37 %, specificity of 97 %, a positive predictive value of 96 % and a negative predictive value of 35 % for the SIST-score in detecting TGDCs, which resulted in an AUC of 0.67. In addition, internal echogenicity (P < 0.01) and margin definition (P < 0.01) were significantly associated to TGDC diagnosis whilst location and multilocularity were deemed insignificant following Bonferroni correction. CONCLUSION: We conclude that the SIST-score seems very capable to rule in TGDC. However, the SIST-score is far from making a clear distinction between DC and TGDCs preoperatively. The addition of other ultrasound variables, such as margin definition and echogenicity, might increase the diagnostic accuracy and demands further research.

Diagnosing Midline Neck Masses: Comparing Clinical Exam, the SIST Score, and the 4S Algorithm.

OBJECTIVE: To validate and compare novel ultrasound scoring systems for dermoid cysts and thyroglossal duct cysts among pediatric patients. STUDY DESIGN: Retrospective study. SETTING: Tertiary care children's hospital. METHODS: An electronic medical record query of patients younger than 18 years old who underwent primary excision of a neck mass between January 2005 and February 2022, who underwent preoperative ultrasound, and had final histopathologic diagnosis of either thyroglossal duct cysts or dermoid cysts. This generated 260 results, of which 134 patients met the inclusion criteria. Charts were reviewed for demographic data, clinical impressions, and radiographic studies. Radiologists blindly reviewed ultrasound for SIST score (septae + irregular walls + solid components = thyroglossal), and 4S algorithm (Septations, depth relative to Strap muscles, Shape, Solid parts). Statistical analyses were performed to determine the accuracy of each diagnostic modality. RESULTS: Of 134 patients, 90 (67%) had a final histopathologic diagnosis of thyroglossal duct cysts, and 44 (33%) were dermoid cysts. The accuracy of clinical diagnosis was 52%, and preoperative ultrasound report accuracy was 31%. The 4S and SIST accuracies were each 84%. CONCLUSION: Both the 4S algorithm and SIST score provide increased accuracy of diagnosis relative to standard preoperative ultrasound assessment. Neither scoring modality was determined to be superior. Further research is warranted in improving the accuracy of preoperative assessments for pediatric congenital neck masses.

[Hyoid body morphology of thyroglossal duct cyst: a comparative study based on imaging].

Objective:To provide reference for preoperative diagnosis and treatment of thyroglossal duct cyst by studying the morphological changes of hyoid body. Methods:The CT data（midsagittal image） of congenital thyroglossal duct cyst（TGDC group） diagnosed by pathology and the control group（C group） were collected from January 2016 to October 2021. The differences of hyoid body height（HBH）, hyoid body width（HBW）, hyoid bone thickness（HBT）, HBW/HBH, HBT/HBH between the two groups were compared. HBH, HBW and HBT were analyzed by t-test; The HBW/HBH and HBT/HBH were analyzed by Mann-Whitney U test. Results:Twenty-nine cases were included in the TGDC group and 58 in the C group. The HBH in the TGDC group was（8.93 ±0.22） mm and that in the C group was（8.94±0.12） mm, there was no significant difference between the two groups（P>0.05）. The HBW in the TGDC group and the C group were（5.09±0.21） mm and（4.48±0.11） mm, and the HBT were（3.84±0.12） mm and（3.13±0.08） mm, respectively, the difference between the two groups was statistically significant（P<0.05）. The average rank sum of HBW/HBH in the TGDC group and the C group was 53.95 and 39.03, respectively, and the average rank sum of HBT/HBH was 59.90 and 36.05, respectively, the difference between the two groups was statistically significant（P<0.05）. Conclusion:The morphological changes of hyoid body of thyroglossal duct cyst may be helpful for preoperative diagnosis, and it also suggests that hyoid body resection may reduce the possibility of postoperative recurrence.

Endoscopic management of intralingual thyroglossal duct cysts: Case series and systematic review.

OBJECTIVE: To discuss our institutional experience with endoscopic management of intralingual thyroglossal duct cyst (TGDC) and review cases in the published literature in a systematic review. METHODS: Pediatric patients with intralingual TGDC treated with endoscopic surgery at our institution from 2009-2019 were identified. Metrics from our case series were then compared to those in the literature in a systematic review to assess pooled outcomes of endoscopic or transoral management. Patient demographics, age of presentation, presenting symptomatology, size of cyst on imaging, type of surgery, and post-operative outcomes were assessed. RESULTS: We identified 5 institutional cases of intralingual TGDC and 48 cases of intralingual TGDC described in the literature. The average age of presentation was 20.36 months. 69.8% (N=37) of patients presented with at least one respiratory symptom, 22.6% (N=12) presented with dysphagia, 9.4% (N=5) presented with an identified mass in the oropharynx, and 15.1% (N=8) had the cyst discovered as an incidental finding. Three patients required revision surgeries due to prior incomplete TGDC excisions and one patient experienced a recurrence >6 months after primary excision requiring a second procedure. Our data pooled with published case series in systematic review confirms that endoscopic or transoral management are excellent options for definitive management of intralingual TGDC. CONCLUSIONS: Intralingual TDGC is a potentially life-threatening variant of TGDC. Our results pooled with published series in a systematic review suggest that endoscopic or transoral management of intralingual TGDC are excellent minimally invasive treatments with a low risk of recurrence. Postoperative surveillance up to one year is recommended.

Synchronous carcinoma of thyroglossal duct cyst and native thyroid gland.

The unobliterated portion of embryological thyroglossal duct may present as cystic swelling later in life and may contain functional thyroid follicles. This cyst requires excision along with the entire thyroglossal duct remnant and adjacent portion of hyoid bone. At times, the excised specimen could demonstrate a focus of carcinomatous change inside the cyst wall. Very rarely, this thyroglossal duct cyst carcinoma could be associated with malignancy of native thyroid gland. This case report illustrates an interesting case of synchronous carcinoma of thyroglossal duct cyst and native thyroid gland. It also sheds light on the controversies related to the pathophysiology of such association and the dilemmas surrounding the management of thyroglossal duct cyst carcinoma, with or without concurrent carcinoma of thyroid gland.

[Ectopic thyroid carcinoma in front of hyoid bone misdiagnosed as thyroglossal cyst：a case report].

A clinical case of ectopic thyroid carcinoma in front of hyoid bone was reported in this paper. The patient, a 17-year-old female, presented with an enlarging neck mass of 1-week history. Physical examination revealed a 3 cm×2 cm neck mass in front of the hyoid bone. Ultrasonographic depicted as a cystic solid mixed echogenic mass with punctate strong echogenicity. CT scan showed a cystic-solid mass in front of the hyoid bone with punctate calcifications. The patient was misdiagnosed as a thyroglossal duct cyst and underwent surgery. The final pathological diagnosis was papillary thyroid carcinoma with cyst formation.

Epidermoid cyst mimicking a thyroglossal duct cyst in a pediatric patient: a case report.

This article presents a case of an epidermoid cyst that mimicked a thyroglossal duct cyst in a pediatric patient. An 8-year-old boy was referred for evaluation of a volumetric increase in the median cervical region with an evolution of about 4 years. The skin in the submental region was healthy and normal colored. Palpation revealed a mobile, well-circumscribed nodular lesion of soft consistency. Computed tomography of the neck showed an expansive hypodense formation extending from the base of the tongue to the upper portion of the hyoid bone, suggesting a thyroglossal duct cyst. Considering the diagnostic hypothesis, cystic enucleation via the Sistrunk procedure was planned. However, no ductal structure was identified during the surgical procedure, and the lesion was only near, but not attached to, the hyoid bone. Simple excision of the lesion was therefore performed. At the most recent follow-up examination, about 3 months postoperatively, the patient demonstrated satisfactory clinical progress. The epidermoid cyst close to the hyoid bone presented diagnostic difficulty due to its similarity to a thyroglossal duct cyst. Computed tomography provides limited information for diagnosing this type of lesion, and ultrasonography is the preferred test. In view of the uncertain diagnosis in this case, the extent of the excision was determined during the surgery, and simple excision was a satisfactory treatment associated with a good prognosis.

Characteristics of lingual thyroglossal duct cysts under flexible laryngoscopy and treatment approaches.

OBJECTIVES: Lingual thyroglossal duct cysts (LTGDCs) are clinically rare and easily misdiagnosed as epiglottic cysts. Misdiagnosis leads to mistreatment; thus,simple diagnosis is important. This study aimed to investigate the characteristics of LTGDCs with flexible laryngoscopy and imaging, improve their diagnosis and explore surgical methods for patients undergoing an initial operation and patients with recurrence. METHODS: In total, 10 patients with LTGDCs were admitted from April 2014 to December 2020.By reviewing the diagnosis and treatment of the first typical case, the characteristics of LTGDC under flexible laryngoscopy were summarized. According to these characteristic manifestations, a clinical diagnosis of LTGDC was made correctly in the other 9 patients. All 10 patients underwent preoperative CT of the neck and sagittal reconstruction and thyroid ultrasound. RESULTS: Of the 10 patients, the first 2 patients had recurrent LTGDCs after several operations and underwent Sistrunk surgery. The remaining 8 patients were newly diagnosed and underwent endoscopic radical resection with low-temperature coblation; of these patients, 7 had no recurrence, and 1 underwent Sistrunk surgery after developing short-term recurrence. All patients were followed up for 5 months to 6 years after the last operation and were without recurrence. CONCLUSION: LTGDCs are easily misdiagnosed as epiglottic cysts in the clinic. A correct clinical diagnosis can be made based on the characteristics according to flexible laryngoscopy. To determine the relationship between the cyst and hyoid bone, CT was performed. The surgical method was chosen based on the relationship between the cyst and hyoid bone and history of recurrence.

Clinical and cytopathological features of suspected thyroglossal duct cysts and neoplasms arising from them: A large series from a referral cancer center.

BACKGROUND: Thyroglossal duct cysts (TGDCs) are the most common congenital midline cystic lesions in the neck, and they are often evaluated by fine-needle aspiration. Recognizing the cytomorphologic features of TGDCs and their mimics is important for clinical management. METHODS: This study examined the clinical, radiological, and cytopathological features of 86 ultrasonography-guided fine-needle aspiration (US-FNA) specimens from clinically suspected TGDCs or malignancies arising from TGDCs and correlated the findings with surgical follow-up and/or imaging studies. RESULTS: According to ultrasound examinations of 66 lesions, 17 (25.8%) were cystic, 8 (12.1%) were cystic with septations, 21 (31.8%) were cystic with solid nodules, and 20 (30.3%) were solid or cystic with internal debris. Cytopathologically, 81 lesions (94%) were categorized as benign, 2 (2%) were categorized as atypical, and 3 (3%) were categorized as malignant. In benign lesions, proteinaceous material (63%), histiocytes (63%), colloid (37%), squamous cells (35%), columnar cells (32%), follicular cells (15%), inflammatory cells (9%), and multinucleated giant cells (9%) were noted. Diagnoses in the benign category included TGDC in 64 patients (75%), TGDC or mimics (colloid nodule/epidermoid cyst) in 14 patients (17%), a colloid nodule in 1 patient, and thyroiditis in 1 patient. Surgical resection, performed in 23 patients, confirmed TGDCs in 12, benign mimics in 7, and carcinoma in 4. CONCLUSIONS: Cytopathological features, in conjunction with imaging, allowed a definite diagnosis of TGDC in most patients (75%). The presence of mature squamous cells, thyroid follicular cells, with or without colloid and/or lymphocytes alone allowed a differential diagnosis of TGDC and its mimics in 17%. US-FNA findings could not distinguish primary carcinomas arising from TGDCs from metastatic tumors.

The effectiveness of ethanol ablation in the treatment of thyroglossal duct cysts in adult cases and evaluation with cosmetic scoring.

PURPOSE: The purpose of this study was to evaluate thyroglossal duct cyst (TGDC) volumes before and after treatment with ultrasound (US) in patients who underwent ethanol ablation (EA). Besides, the usability of cosmetic scoring in TGDC cases was investigated by comparing cosmetic scores pre-treatment and after EA. MATERIALS AND METHODS: 28 TGDC cases who had EA in one session and had complete US data and cosmetic scores were included in the study. US data including TGDC diameters and volumes obtained at the pre-treatment, 3rd, 6th, and 12th month after EA were noted, respectively. Cosmetic scoring was performed pre-treatment and after EA using the WHO grading system simultaneously with US. RESULTS: At the 12th month after EA, there was 85.2% reduction in mean diameter and 95.1% reduction in mean volume in TGDC cases (p < 0.001). The mean cosmetic score pre-treatment was 2.7 ± 0.8 and the mean cosmetic score at the 12th month was 1 (p < 0.001). When the changes in TGDC volumes and cosmetic scoring after EA were compared according to gender and age, there was no statistically significant difference (p > 0.05). CONCLUSION: The current study demonstrated that EA can be used safely to reduce TGDC sizes and is an alternative treatment option to surgery.

A new transoral modality for the treatment of lingual thyroglossal duct cyst with suspension laryngoscopy by plasma coblation.

INTRODUCTION: Lingual thyroglossal duct cysts (LTGDC) are a rare kind of thyroglossal duct cyst. However, Sistrunk surgery is not very suitable for this type of cyst. This study aimed to explore the efficacy of transoral excision of LTGDC by plasma coblation. METHODS: The present study reviewed 11 patients, comprising seven males and four females, who had been diagnosed with LTGDC preoperatively by computed tomography (CT) and fibre-optic electronic laryngoscopy. Of those patients, two had recurrence after surgery of epiglottic cysts. All these patients underwent transoral excision by plasma coblation. Then, we collected preoperative data of the patients, observed the effect of surgery, and analysed factors relevant to LTGDC, including the estimated bleeding amount, postoperative hospitalisation, complications and recurrence rates. RESULTS: The connection between LTGDC and hyoid was tapered on sagittal images of CT, which was vital evidence for the diagnosis of LTGDC. Surgery was performed successfully for all 11 patients, and all recovered without complication. There was no evidence of recurrence after surgery, during follow up for 3-43 months. CONCLUSIONS: Transoral surgery for LTGDC can be performed successfully by plasma coblation, which is an effective and safe surgical treatment. Fibre-optic electronic laryngoscopy and CT are essential to the diagnosis of LTGDC in order to avoid missing detection and misdiagnosis.

Large thyroglossal duct cyst of the neck mimicking cervical cystic lymphangioma in a neonate: a case report.

Thyroglossal duct cyst (TGDC) is a congenital neck malformation, with a rate of approximately 7% in paediatric patients. TGDC is rarely detected in infants aged younger than 1 year. Even though TGDC is histologically benign, it is associated with preterm delivery or sudden infant death due to airway obstruction, with a mortality rate of 30% to 40%. We report a rare case of a neonate who presented with a large left lateral neck mass. At 7 to 8 months of gestation, magnetic resonance imaging of the foetal neck showed that there was a high possibility of a cervical cystic lymphangioma. The patient had normal vital signs and was afebrile. She was immediately transferred to our Ear, Nose, and Throat Department for further diagnosis and treatment. A computed tomography scan confirmed a large cystic mass that was positioned against a thyroglossal duct. Excision of the mass in the left neck was performed under general anaesthesia without resecting part of the hyoid bone. A histopathological examination confirmed the diagnosis of a TGDC. Follow-up at 1 year showed no recurrence.

Proposed ultrasound algorithm to differentiate thyroglossal duct and dermoid cysts.

OBJECTIVE: 1) To assess reproducibility of the previously established SIST score. 2) To determine inter-observer agreement in using ultrasound (US) characteristics to differentiate thyroglossal duct cyst (TGDC) from dermoid cysts (DC) 3) Improve the method used to pre-operatively differentiate TGDC from DC. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary care pediatric hospital. SUBJECTS AND METHODS: An electronic medical record was queried to identify children with midline neck masses who underwent pre-operative neck US and had a histopathologic diagnosis of either TGDC or DC. Two pediatric radiologists, blinded to the pathologic diagnosis, evaluated the US images and documented the presence of pre-determined characteristics of each mass. Potential differentiating factors were analyzed for their predictive power. The SIST (septations, irregular walls, solid components = TGDC) score was determined as well as inter-observer agreement. Using the characteristics that had significant predictive power, we used the data to develop an algorithm to improve predicting cyst type. RESULTS: Pathologically, there were 47 TGDC and 25 DC. The inter-observer agreement about the pathologic diagnosis between the two radiologists was substantial, K = 0.66. Overall, the SIST score predicted the correct diagnosis 67% of the time. Radiologist 1 and radiologist 2 were more accurate than the SIST score alone, making the correct diagnosis 96% and 86% of the time, respectively. In our study, we found that the most important US characteristics in differentiating TGDC and DC are: internal Septations, depth relative to Strap muscles, Shape and Solid parts (4 S algorithm). The SIST score criteria were individually shown to be significant and sensitive in recognizing DC, however, they were not specific and often misclassified TGDC as DC. We developed a new sequential filtering algorithm that more accurately differentiates cysts. This new algorithm uses step-wise filtering of characteristics, first for Septations, then for depth to Straps, then Shape of the cyst and lastly Solid parts (4 S algorithm). This algorithm correctly categorized cyst type in 100% of patients in our study. CONCLUSIONS: Pre-operatively differentiating TGDC and DC continues to be a challenge. Using our 4 S algorithm, we can more definitively differentiate TGDC from DC compared to the SIST score. All SIST score characteristics were significant and sensitive in detecting dermoid cysts, however, not very specific. The radiologists' judgment and accuracy was better than the SIST score. The 4 S algorithm uses sequential filtering of important characteristics: Septations, depth to Straps, Shape of cyst and lastly Solid parts to improve diagnostic accuracy.