Asian Cardiovasc Thorac Ann 2006;14:476-478
© 2006 Asia Publishing EXchange Ltd
Asymptomatic Solitary Mediastinal Cystic Lymphangioma: A Rare Entity
Panagiotis Misthos, MD,
Evangelos Sepsas, PhD,
Ioannis Kokotsakis, MD,
Ion Skottis, MD
First Thoracic Surgical Department, Sotiria General Hospital for Chest Diseases, Athens, Greece
For reprint information contact: Panagiotis Misthos, MD Tel: 30 210 252 9048 Fax: 30 210 252 9048 Email: panmisthos{at}yahoo.gr, 7 P. Dimitrakopoulou Street, Athens 11141, Greece
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ABSTRACT
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Solitary mediastinal cystic lymphangioma is an extremely rare tumor-like abnormality of the lymphatic system, of congenital origin. From 1996 to 2003, 4 cases of solitary mediastinal cystic lymphangioma were managed in our department. The clinicopathologic characteristics were recorded and analyzed. The incidence proved to be 1.2% among all cases of mediastinal masses admitted to our department. All patients were asymptomatic, they shared common radiologic features, and all were managed by radical surgical excision. No recurrence or mortality were noted during follow-up ranging from 2 to 7 years. Complete excision of this benign entity has an excellent prognosis.
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INTRODUCTION
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Cystic lymphangioma is an extremely rare tumor of the mediastinum, especially when it is confined only to mediastinum. It is a congenital developmental malformation of unknown etiology, which involves the lymphatic system. Agenesis or obstruction of lymphatic channels leads to abnormal dilatation that eventually causes the formation of a cystic mass. Most lymphangiomas occur in the neck (75%) and axilla (20%).1,2 Less than 1% of all lymphangiomas present as a solitary mediastinal mass.3 Very few previous cases of solitary cystic lymphangioma in the superior mediastinum have been reported.4,5 We describe 4 cases of this extremely uncommon clinical entity, which were detected incidentally.
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PATIENTS AND METHODS
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In the last decade, 327 patients with mediastinal tumors were investigated in our department. These patients were subjected to diagnostic procedures and 172 (52.6%) of them were managed surgically. The tumors were studied preoperatively by chest radiography and computed tomography (CT) scanning. Their location, size, and relationships to other adjacent structures were recorded, as well as the clinical signs and symptoms. An experienced pathologist evaluated all histological specimens and ambiguous cases were excluded from this study.
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RESULTS
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From January 1996 to January 2003, 4 cases (1.2%) of solitary mediastinal cystic lymphangioma were managed in our department. The patients were all male, aged 23–54 years (mean age, 38.7 years), and none had symptoms or signs in their medical history. All 4 tumors were detected incidentally in a routine examination. No underlying disease existed.
On CT scanning, a common image was noted: a unilocular homogeneous well-circumscribed mass at the right paratracheal region of the upper mediastinum, lateral to the superior vena cava (Figure 1
). The diameters of the lesions ranged from 7 to 13 cm (mean, 9.5 cm). The findings from CT imaging posed a serious diagnostic problem as to the exact nature of the masses. Fiberoptic bronchoscopy was negative, as well as upper abdominal CT scanning. All patients were investigated for possible thyroid gland disease (thyroid hormone levels, thyroid ultrasonography, and thyroid scanning). The differential diagnosis included thymic cysts and bronchogenic cysts.
All patients were subjected to a muscle-sparing lateral minithoracotomy. Fine-needle aspiration of the mass was performed before any dissection took place. This yielded a thin yellow fluid in all cases. Complete cyst excision was feasible in all cases. In all except one case, it was possible to create a plane of dissection from the superior vena cava. The cyst wall was removed along with a narrow strip of the wall of the superior vena cava, which was reconstructed by suturing. The postoperative course was uneventful and the mean hospital stay was 5 days. The pathologic diagnosis was cystic lymphangioma. The follow-up ranged from 2 to 7 years (mean, 4.2 years) and no recurrences were detected.
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DISCUSSION
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Cystic lymphangioma is a tumor-like congenital developmental abnormality of the lymphatic system. Lymphangiomas have been classified into three groups: lymphangioma simplex, composed of capillary-sized thin-walled lymphatic channels; cavernous lymphangioma, composed of dilated lymphatic channels, often with fibrous adventitia coats; and cystic lymphangioma or cystic hygroma, composed of cysts that range from a few millimeters to several centimeters in diameter.2,6 Rarely, they are associated with lymphangiomatosis, which is a generalized process with a dismal outcome. They are most likely congenital malformations that result from inability of the lymphatic system to communicate with the venous system, leading to deficient lymph drainage. If this happens in a location where expansion is permitted due to a larger space and a looser, less-compact tissue structure, a cystic hygroma develops. This is characterized by endothelial-lined spaces that vary widely in size and wall thickness, and contain lymphoid tissue. We believe all 4 of our cases were of this kind. We also noted that despite the benign nature of this entity, 2 of the 4 tumors showed a tendency to infiltrate the mediastinal organs, especially the superior vena cava which was invaded by the cyst wall without obstruction. This made complete excision technically demanding.
Less than 1% of all lymphangiomas present as a solitary mediastinal mass; mediastinal cystic hygromas are usually extensions of neck lymphangiomas.3 In this study, of the 327 mediastinal tumors referred to the thoracic surgery department for diagnosis and/or treatment, only these 4 (1.2%) were solitary mediastinal lymphangiomas. Previous reports gave incidences of 1.7% and 2.8%, but although the lesions were stated to be primary mediastinal lymphangiomas, it is not clear whether they were solitary lesions.7,8 All cases were confined to the superior mediastinum, which is in contrast to a previous report.4 Most reported cases have been extensions of cystic hygromas of the neck.
Cystic lymphangioma is incidentally detected, as most often the patient shows no symptoms or signs. Chest pain, dyspnea, and cough are noted when the tumor grows to a large size. Our patients presented with no symptoms and were diagnosed by the finding of a radiographic abnormality during routine examination. Taking into consideration the diameter of these tumors, which ranged from 7 to 13 cm, it seems likely that cystic lymphangiomas do not cause symptoms until they acquire large dimensions (probably more than 14 cm). Differential diagnosis includes other masses of the superior mediastinum including thymic, enterogenous, and bronchogenic cysts, tumors such as thymomas, lymphomas, and teratomas, as well as aneurysmal dilatation of the brachiocephalic trunk. The radiographic image of cystic lymphangioma is a well-described rounded unilocular mass of homogeneous density, without calcification. Although this differentiates them from low-density tumors (thymoma, lymphoma, teratoma), it is impossible to define the nature of the mass and distinguish it from cystic lesions in the differential diagnosis.9–11 Only complete excision of the cyst can establish a solid pathologic diagnosis.
The treatment of choice is complete surgical excision, which might be a rather demanding operation when vital structures are affected, such as the superior vena cava, vagus nerve, or phrenic nerve. Although generally located close to the lymphatic duct, no case of chylothorax was documented. The cystic wall contains infiltrates that strongly predispose to recurrence. Complete excision of this benign entity has an excellent prognosis. Although complete surgical resection is traditionally considered the treatment of choice, there is controversy as to whether surgical excision is always indicated. The opponents of surgical management state that malignancy is rarely associated with mediastinal cysts in general.12 Furthermore, they are asymptomatic without compression of any vital structures. Observation is advocated. On the other hand, the natural history of such big cysts is practically unknown and there are no guarantees that they will not enlarge causing compression of vital structures, or rupture, or become infected. In addition, there may be considerable lung compression at the time of diagnosis. We believe that since no evidence-based data are available for the time being, one should not change the current policy that is followed by the majority of thoracic surgeons.
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REFERENCES
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- Rekhi BM, Esselstyn CB Jr, Levy I, Mercer RD. Retroperitoneal cystic lymphangioma. Report of two cases and review of the literature. Cleve Clin Q 1972;39:125–8.[Medline]
- Singh S, Baboo ML, Pathak IC. Cystic lymphangioma in children: report of 32 cases including lesions at rare sites. Surgery 1971;69:947–51.[Medline]
- Brown LR, Reiman HM, Rosenow EC 3rd, Gloviczki PM, Divertie MB. Intrathoracic lymphangioma. Mayo Clin Proc 1986;61:882–92.[Medline]
- Topcu S, Soysal O, Balkan E, Yalcinkaya I, Demircan S, Gulhan E. Mediastinal cystic lymphangioma: report of two cases. Thorac Cardiovasc Surg 1997;45:209–10.[Medline]
- Nakazato Y, Ohno Y, Nakata Y, Yamaguchi H, Hazato N, Nagasawa S, et al. Cystic lymphangioma of the mediastinum. Am Heart J 1995;129:406–9.[Medline]
- Bill AH Jr, Sumner DS. A unified concept of lymphangioma and cystic hygroma. Surg Gynecol Obstet 1965;120:79–86.[Medline]
- Wychulis AR, Payne WS, Clagett OT, Woolner LB. Surgical treatment of mediastinal tumors: a 40 year experience. J Thorac Cardiovasc Surg 1971;62:379–92.[Medline]
- Glasson MJ, Taylor SF. Cervical, cervicomediastinal and intrathoracic lymphangioma. Prog Pediatr Surg 1991;27:62–83.[Medline]
- Kittredge RD, Finby N. The many facets of lymphangioma. Am J Roentgenol Radium Ther Nucl Med 1965;95:56–66.[Medline]
- Nanson EM. Lymphangioma (cystic hygroma) of the mediastinum. J Cardiovasc Surg (Torino) 1968;9:447–52.[Medline]
- Chervenak FA, Isaacson G, Blakemore KJ, Breg WR, Hobbins JC, Berkowitz RL, et al. Fetal cystic hygroma. Cause and natural history. N Engl J Med 1983;309:822–5.[Abstract]
- Ponn RB. Simple mediastinal cysts: resect them all? Chest 2003;124:4–6.
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ABSTRACT
INTRODUCTION
