Congenital Neck Masses.

There are many possible causes of congenital neck masses, with the most common ones being thyroglossal duct cysts, branchial cleft anomalies, and vascular malformations. Most congenital neck masses are asymptomatic in the neonatal period, but depending on the location and the size, they can cause airway obstruction and serious complications at birth. Proper diagnosis is important for optimal treatment planning, and if the airway is compromised, multidisciplinary teamwork is critical for proper airway management. This review summarizes the clinical features, etiology, diagnosis, management, and prognosis of different types of congenital neck masses.

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)

Efficacy of ethanol ablation as a treatment of benign head and neck cystic lesions.

OBJECTIVE: To evaluate the efficacy and safety of ethanol ablation in the treatment of benign head and neck cystic lesions. METHODS: A total of 25 patients who received ethanol ablation (EA) of head and neck cystic lesions by an otolaryngologist at a single institution between October 2017 and October 2020 were identified. Patient demographics, clinical characteristics, treatment details, and treatment outcomes at follow up visits were obtained by retrospective review of electronic medical records. RESULTS: 25 patients who underwent ethanol ablation of head and neck cystic lesions were included, with a mean age of 49.1 years old (Interquartile range (IQR),32.5-65.5 years) and 12 males (47.0%). The most common cysts treated with EA were thyroglossal duct cysts (n = 8, 32.0%) and lymphoepithelial parotid cysts (n = 7, 28.0%). The mean volume prior to treatment was 10.57 mL (IQR, 1.58-8.81 mL). Mean volume following EA was 1.30 mL (range, 0.10-0.97 mL) with 74.40% cyst reduction by volume (IQR, 48.56-96.29%) (p = 0.002). The mean time to the last follow-up was 5 months (range, 3-6 months). One patient received surgery despite treatment success to obtain a definitive diagnosis of the mass. No other patients received further surgical management. The treatment success of EA, as defined by >70% volume reduction or the resolution of symptoms, was 92.0%. All patients were satisfied with the outcome and had no reported complications. CONCLUSION: EA is an effective and safe alternative to surgery for the treatment of head and neck cystic lesions that can be performed in an outpatient setting by an otolaryngologist.

Sclerotherapy for Benign Cystic Lesions of the Head and Neck: Systematic Review of 474 Cases.

OBJECTIVE: The role of sclerotherapy for vascular lesions of the head and neck is well established. However, the efficacy of sclerotherapy for benign cystic lesions of the head and neck is less clear. The objective of this review is to determine the efficacy and safety of sclerotherapy for benign cystic lesions of the head and neck. DATA SOURCES: PubMed/MEDLINE, Cochrane Library, and Embase. REVIEW METHODS: The PRISMA guidelines (Preferred Reporting Systems for Systematic Reviews and Meta-analyses) were followed for this systematic review. Studies of patients with benign head and neck cystic masses treated primarily with sclerotherapy were included. Thirty-two studies met criteria for inclusion. RESULTS: A total of 474 cases of sclerotherapy were reviewed. Agents comprised OK-432, ethanol, doxycycline, tetracycline, and bleomycin. Lesions in the analysis were ranula, thyroglossal duct cyst, branchial cleft cyst, benign lymphoepithelial cyst, parotid cyst, thoracic duct cyst, and unspecified lateral neck cyst. A total of 287 patients (60.5%) had a complete response; 132 (27.9%) had a partial response; and 55 (11.6%) had no response. OK-432 was the most widely utilized agent, with a higher rate of complete response than that of ethanol (62.0% vs 39.4%, P = .015). Fifty-three cases (11.2%) required further surgical management. One case of laryngeal edema was reported and managed nonoperatively. CONCLUSION: Sclerotherapy appears to be a safe and efficacious option for benign cystic lesions if malignancy is reliably excluded. Efficacy rates are comparable to those of sclerotherapy for vascular malformations. The rate of serious complications is low, with 1 incident of airway edema reported in the literature.

The efficacy of OK-432 sclerotherapy on thyroglossal duct cyst and the influence on a subsequent surgical procedure.

Background: Although there are studies regarding the efficacy of OK-432 sclerotherapy on thyroglossal duct cyst (TDC), its effects on surgical procedure following this therapy have not been properly described. Objectives: The present study aimed to delineate the prognostic factors of OK-432 sclerotherapy in patients with TDC and investigate its influence on subsequent surgical procedure and the histological characteristics in patients with poor response to OK-432 sclerotherapy. Material and methods: We conducted a retrospective analysis of the medical records of 20 TDC patients treated with OK-432 sclerotherapy. Results: Of the 20 patients, OK-432 sclerotherapy was effective in 5 patients (25.0%). OK-432 showed a lower effective rate in multilocular cysts (9.1%) than in unilocular cysts (44.4%), although not significantly. Five cases were treated with surgery following OK-432 sclerotherapy. There was no significant difference in the operating time and the amount of bleeding between patients with and without OK-432 sclerotherapy. From the results of the histological examination of the cyst wall, two cases had stratified squamous epithelium and two cases showed the absence of lymphocyte infiltration. Conclusion and significance: OK-432 sclerotherapy is an acceptable initial treatment for TDC, especially in unilocular cysts, because of lack of influence on surgical procedure.

Infected Lingual Thyroglossal Duct Cyst Mimicking Supraglottitis.

A thyroglossal duct cyst (TGDC) is a common embryological remnant that typically presents as an anterior neck mass; however, this malformation can occur in any adjacent area, including the tongue base (lingual type), along the migration path of the thyroid during embryonic development. Lingual TGDC is often quiescent until infection occurs. Supraglottitis or inflammation of the supraglottis, is a potentially life-threatening disease. Because of the anatomical proximity of lingual TGDC to the supraglottis, lingual TGDC infection might be related to a presentation of supraglottitis. A 49-year-old male initially presented with clinical symptoms of acute supraglottitis. After intensive medical treatment resulting in no improvement, a computed tomography scan was performed. The result raised the suspicion of an infected lingual TGDC. Transoral marsupialization using a rigid laryngoscope was performed to drain the abscess inside the cyst. A diagnosis of lingual TGDC was made based on the characteristic histological pattern of the lesion. After treatment, a follow-up computed tomography scan showed no evidence of recurrence. To the authors' knowledge, only a few reports have pointed out similarities in the clinical and radiological findings between acute supraglottitis and an infected lingual TGDC. Clinicians should consider lingual TGDC during the differential diagnosis of supraglottitis, especially in patients with poor response to medical treatment.

Management outcome of thyroglossal cyst in a tertiary health center in Southwest Nigeria.

Thyroglossal duct cyst is a non-odontogenic congenital developmental cyst. It is predominantly a midline anterior neck swelling in children and total excision of the tracts prevents recurrence. Retrospective hospital record analysis of patients managed with histopathology results of thyroglossal cyst between 2003 and 2018. Comparing outcomes and technique of thyroglossal cyst excision in a resource challenged environment. A total of 37 patients comprising 22(59.5%) males and 15(40.5%) females (M:F 1.4:1) with age range of 13 days to 55 years (median 6 years) were managed. The majority were children less than 10 years of age. They all presented with a fluctuant midline progressive anterior neck swelling, in addition to anterior neck ulcer 1(2.7%), discharging sinuses 3(8.1%) and thyroglossal cyst duct infections, which were managed successfully with antibiotics. Central compartment neck dissection with excision of mid-portion of the hyoid bone was performed in all the patients. Rupture of thyroglossal duct cysts was observed in 7(18.9%) at surgery, but there was no recurrence. Surgical drain was not used and most patients were discharged within 48 hours postoperatively. Thyroglossal duct cyst was confirmed at histology without any evidence of mitotic changes. There was no recurrence for the Sistrunk's procedure in all specialties. The modification of the Sistrunk's procedure with mid-anterior neck dissection is effective in excising a thyroglossal duct cyst, hence preventing recurrence. Non-usage of wound drains and short hospital stay are cost effective.

Papillary-Type Carcinoma of the Thyroglossal Duct Cyst: The Case for Conservative Management.

OBJECTIVES: Thyroglossal duct cyst (TGDC) is the most common congenital neck mass, presenting in up to 7% of the population. TGDC carcinoma is much less common, occurring in roughly 1% of patients diagnosed with TGDC. The vast majority of these tumors are papillary-type thyroid cancer. Given its rarity, there is wide variation in management recommendations for this disease. Extent of surgical management and need for adjuvant therapy including radioactive iodine ablation (RAI) are particularly debated, with some authors arguing aggressive therapy including RAI for any patients who undergo concurrent thyroidectomy with the Sistrunk procedure for TGDC carcinoma. We present a series of patients treated for TGDC carcinoma at our institutions and discuss our management algorithm. METHODS: This is a retrospective chart review of patients with TGDC treated at 2 separate institutions. Factors reviewed included patient age, sex, preoperative diagnosis, preoperative work-up, extent of therapy, and use of adjuvant therapy. RESULTS: Six patients who were treated for TGDC carcinoma at our institutions were identified. One patient was excluded because the patient had been treated at an outside facility prior to referral. All patients had papillary-type thyroid cancer. One patient underwent the Sistrunk procedure alone, and the remaining 4 underwent the Sistrunk procedure plus total thyroidectomy. Two of 4 patients were noted to have malignancy in the thyroid. Two of 4 patients who underwent thyroidectomy additionally received adjuvant RAI. CONCLUSION: Thyroglossal duct cyst carcinoma is uncommon and management is controversial. In low-risk patients (single tumor focus, negative margins, normal preoperative neck/thyroid imaging, no extension of TGDC carcinoma beyond the cyst wall), the Sistrunk procedure alone with observation of the thyroid may be sufficient. In this patient population, RAI is unlikely to be of any substantial benefit.

[Cancer of the thyroglossal duct]. / Rak shchitoiazychnogo protoka.

The authors present the clinical observation of the cancer of the tongue-lingual duct together with the concise overview of the relevant literature and the discussion of etiology and pathogenesis of this condition.

Synchronous malignancies of thyroglossal duct cyst and thyroid gland.

Malignant involvement of thyroglossal duct cyst is rare, still rarer is the synchronous malignant involvement of the thyroid gland. Although the Sistrunk procedure is often regarded as adequate, controversy exists of the need for an additional total thyroidectomy and radioiodine ablative therapy, the decision of which depends upon the presence of (i) suspicious thyroid gland nodule; (ii) presence of lymphadenopathy; or (iii) a previous history of neck irradiation. We report a 47-year-old woman diagnosed with papillary carcinoma within a recurrent thyroglossal duct cyst with infiltration into surrounding soft tissues and a suspicious thyroid nodule of the left thyroid lobe with no regional lymph node involvement. On final histopathology, the left thyroid nodule had a follicular variant of papillary carcinoma thyroid without regional nodal involvement. The patient underwent total thyroidectomy with radioactive iodine postoperatively.

Treatment Efficacy and Safety of Ethanol Ablation for Thyroglossal Duct Cysts: A Comparison with Surgery.

OBJECTIVE: To compare the efficacy and safety of ethanol ablation (EA) for thyroglossal duct cyst (TGDC) against surgery. METHODS: This study included 345 patients (289, surgery; 56, EA) treated for TGDC at four institutions between May 2005 and June 2014. Surgery (whole surgery and Sistrunk operation which is the current standard surgical method) and EA were compared with respect to the treatment failure and complication rates. The cost of EA and surgery was also compared. The Cox regression hazard model and linear regression were used for the adjustment of covariates. RESULTS: EA demonstrated higher treatment failures (19.6% vs. 2.4%, p < 0.001[whole surgery] and 1.2%, p = 0.004 [Sistrunk operation]), but fewer complications (1.8% vs. 10.0%, p = 0.04 [whole surgery] and 10.2%, p = 0.06 [Sistrunk operation]), and lower cost (₩423,801 vs. ₩1,435,707 [whole surgery]) than surgery. EA achieved 85.7% of treatment success up to second session. The mean volume reduction rate after EA was 82.3% at last follow-up. Young age and EA were correlated with treatment failure (p = 0.01 and 0.001, respectively). CONCLUSION: Both surgery and EA had acceptable treatment efficacy in the management of TGDC. Although there is a higher likelihood of treatment failure with EA, it has a better safety profile than surgery. KEY POINTS: • Both surgery and ethanol ablation show acceptable treatment efficacy for TGDC. • Considering treatment failure, surgery manages TGDC more effectively than EA. • EA is safer than surgery and presents no major complications. • EA could be an alternative treatment for TGDC in selected patients.

Incidental radiographic findings of thyroglossal duct cysts: Prevalence and management.

OBJECTIVES/HYPOTHESIS: To determine the epidemiology of incidental thyroglossal duct cysts (TGDC) discovered on imaging studies obtained in the head and neck area in children and to discuss subsequent management. METHODS: A retrospective chart review was performed at Texas Children's Hospital of all computed tomography (CT) and magnetic resonance (MR) imaging studies obtained in the head and neck region between July 2011 and July 2014. Images obtained for the purpose of evaluating a neck or lingual mass were excluded from the study, as were patients with previously known TGDCs. Data including age, sex, location of TGDC, size, presence of symptoms, referral to Otolaryngology, and intervention were recorded. RESULTS: A total of 60,663 CT and MR studies of the head, brain, sinus, neck, and C-spine during this time period were reviewed; of these 69 (0.1%) cases contained incidental discovery of probable TGDCs with more males (40) than females (29). Ages ranged from 3 days to 17 years old, with the mean age at 5 years. Locations varied, with majority at base of tongue (83%) followed by hyoid (13%) then infrahyoid straps (4%). Sizes ranged from 2 to 28 mm with average size at 8 mm. 11 of these patients were referred to an Otolaryngologist; 9 were asymptomatic and decision was made to observe, the other two subsequently underwent surgical excision secondary to mass effect and dysphagia with histologic confirmation of diagnosis. CONCLUSION: TGDCs commonly present as an anterior neck mass, however the majority of incidentally discovered TGDCs on imaging are located at the base of tongue. Management of these findings should include referral to an Otolaryngologist for further evaluation with the decision to intervene surgically based on development of clinical symptoms.

Doxycycline: A sclerosant agent to treat a case of recurrent thyroglossal duct cyst.

Thyroglossal duct cyst (TGDC) is one of the most common congenital anterior midline neck masses in children. Sistrunk operation is considered as the cornerstone in TGDC removal. Nevertheless, 5% to 7 % of patients have been reported to show a recurrence even after adequate resection. This necessitates at times multiple resections with potential complications. One interesting emerging technique is sclerotherapy of TGDC remnants post resection. We present here a case of a child who had a successfully treated recurrent TGDC using sclerotherapy with doxycycline.

Malformaciones congénitas del cuello. Diagnóstico y tratamiento / Congenital neck mass. Diagnosis and treatment

Las alteraciones congénitas del cuello constituyen un desafío para los médicos de familia y los especialistas. Aunque algunas de ellas son diagnosticadas de forma intrauterina, la mayoría permanecen silentes y se manifiestan en el contexto de infecciones a lo largo de la vida. La localización anatómica, la consistencia y la edad son determinantes en la orientación del posible diagnóstico. Una masa cervical en línea media infrahioidea hará pensar en un quiste tirogloso. Si es lateral, descartaremos un quiste braquial. Los estudios complementarios por imagen son fundamentales, sin olvidar pruebas anatomopatológicas como punción aspiración de aguja fina (PAAF) (AU)

Congenital neck masses are a challenge for general practitioners and specialists. Although some of them are diagnosed in utero, most of them remain silent until complications appear in the adult age. The anatomical location, consistency and age are determinants in guiding the possible diagnosis. A midline infrahyoid mass may be a thyroglossal cyst, however a lateral neck mass is more possible to result in a brachial cyst. Complementary imaging studies are essential such as pathological tests like needle aspiration fine needle aspiration (FNA) (AU)

Squamous cell carcinoma in a thyroglossal duct cyst: A case report with review of the literature.

Carcinoma arising within a thyroglossal duct cyst (TGDC) is exceedingly uncommon, occurring in about 1% of TGDC (Chrisoulidou et al., 2013 [1]). Since the first description of TGDC carcinoma in 1911 by Brentano, approximately 200 cases have been reported in the world literature, mostly as single case reports making its true incidence difficult to determine (Hanna, 1996 [2]). There are numerous reports in the literature of papillary and follicular TGDC carcinoma, but only limited reports of squamous cell carcinoma. In order for a lesion to qualify as squamous cell carcinoma of a TGDC, the lesion must arise from the epithelial lining. Recognition and understanding of this entity are important in staging and planning of treatment. Exclusion of primary squamous cell carcinoma arising from an adjacent structure or metastatic central compartment nodal disease is important in the evaluation for diagnosis to be confirmed. A thorough work up should be undertaken to exclude other primary malignancies that may have metastasized. We present a unique case of squamous cell carcinoma, along with supporting pathology and radiology imaging. We then review this rare entity and provide some insight into the diagnosis and management.

Efficacy of ethanol ablation for thyroglossal duct cyst.

OBJECTIVE: Ethanol ablation has been known as an effective, easy, and safe treatment of cystic thyroid lesions. The objective of the present study was to evaluate efficacy of ethanol ablation as a minimally invasive management of thyroglossal duct cyst (TGDC). METHODS: Between January 2012 and July 2013, 9 TGDC patients were diagnosed and treated with ethanol ablation. We evaluated the treatment outcomes with the change of volume reduction and the improvement of symptomatic and cosmetic complaints and complications. RESULTS: Initial mean tumor volume was 8.9 mL (range, 0.2-36.9 mL) in ultrasonography. The mean number of the treatment sessions was 1.7 (range, 1-3 sessions). At last follow-up, the mean volume of the treated thyroglossal duct cyst decreased significantly from 8.9 mL to 1.9 mL (P = .019; volume reduction rate = 76.6%). Treatment success rate was 77.8% (7/9). Mean symptoms and cosmetic-grading scores improved from 5.2 to 3.1 and from 5.3 to 3.1 (P = .062). No significant complications were observed during follow-up. CONCLUSION: Ethanol ablation is a feasible and convenient procedure without surgical scars and hospitalization for TGDC patients. Favorable outcomes can be achieved without significant complications.

Carcinoma papilar en quiste tirogloso. Propuesta de algoritmo diagnóstico y terapéutico / Papillary carcinoma in a thyroglossal duct cyst. Proposal of an algorithm for diagnosis and treatment / Carcinoma papilar em cisto tirogloso: proposta de algoritmo diagnóstico e terapêutico

Antecedentes: el carcinoma diferenciado de tiroides en quiste tirogloso (CaQT) es una entidad rara. La incidencia de CaQT es de 1 a 2%. Usualmente su forma de presentación clínica es indistinguible de una lesión benigna y el diagnóstico definitivo es postquirúrgico. No hay en la actualidad un consenso sobre la indicación de tiroidectomía total, radioablación con iodo y/o terapia supresiva con levotiroxina luego de ser extirpado quirúrgicamente...

Introduction: the development of well -differentiated thyroid carcinoma in thyroglossal duct cysts (TGDCa) is uncommon. The incidence of TGDCa lies within 1 to 2%. Usually the clinical appearance is indistinguishable from a benign thyroglossal duct cyst. The definitive diagnosis is post-operative. After the surgery of choice, the other alternative treatments such as thyroidectomy, radioiodine and L-T4 therapy are controversial...

Antecedentes: o carcinoma diferenciado de tireoide em cisto tirogloso (CaQT) é uma entidade rara. A incidência de CaQT é de 1 a 2 por cento. Em geral, a sua forma de apresentação clínica é indistinguível de uma lesão benigna e o diagnóstico definitivo é pós-cirúrgico. Não existe atualmente um consenso sobre a indicação de tiroidectomia total, radioablação com iodo e/ou terapia supressiva com levotiroxina após ser extirpado cirurgicamente...

Thyroglossal duct cysts: anatomy, embryology and treatment.

Thyroglossal duct cysts are the most frequently encountered congenital abnormality of the neck, and are described extensively in the literature. The high incidence of this abnormality and its presence in all age groups requires clinicians to be aware of the clinical features, etiology, and current treatment options. Because it is readily accessible, relatively inexpensive, and non-invasive, sonography is arguably the ideal initial investigation. Computerized tomography and fine needle aspiration biopsy are often utilized as supplementary techniques for confirmation of the diagnosis. The treatment of choice for thyroglossal duct cysts continues to be the classic Sistrunk procedure, developed in 1920, although several modifications have since been employed. In this review, we aim to explore the embryological development, clinical presentation and diagnostic features of thyroglossal duct cysts. In addition, a useful adaptation to the Sistrunk procedure and the recent application of OK-432 therapy as a promising alternative for treatment of thyroglossal duct cysts will also be discussed.

Failure of sclerotherapy in the treatment of thyroglossal duct cyst in children: 2 case reports and review of the literature.

Thyroglossal duct cyst (TGDC) is one of most common congenital diseases of the midline of the neck. Most TGDC cases require treatment in the cases of cosmetic problems or recurrent infection, and a Sistrunk operation is considered to be the standard treatment. However, less invasive treatments are sometimes used, and sclerotherapy with OK-432 or ethanol is one such method. However, the validity or use of sclerotherapy as a TGDC treatment is controversial because cases of TGDC that have been successfully treated with sclerotherapy are rare, and the follow-up period is short, and there are no statistical reports about the reoccurrence of symptoms after sclerotherapy. In this report, we review 2 recurrent TGDC cases after sclerotherapy with OK-432 and ethanol and discuss the efficacy and limitations of sclerotherapy.