Ann Thorac Surg 1999;68:1857-1858
© 1999 The Society of Thoracic Surgeons
Case Reports
Postoperative mediastinal chyloma
Kenji Suzuki, MDa,
Junji Yoshida, MDa,
Mitsuyo Nishimura, MDa,
Kenro Takahashi, MDa,
Kanji Nagai, MDa
a Division of Thoracic Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan
Address reprint requests to Dr Suzuki, Division of Thoracic Surgery, National Cancer Center Hospital, 5-5-1, Tsukiji, Chuoku, Tokyo 104-0045 Japan
e-mail: kjsuzuki{at}ncc.go.jp
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Abstract
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Anterior mediastinal mass developed in a 69-year-old woman who had undergone right upper lobectomy and systematic lymph node dissection. The mass was diagnosed to be a mediastinal chyloma and surgical intervention was necessary to resolve the compression to the superior vena cava. Although posttraumatic mediastinal chyloma is not rare, postoperative mediastinal chyloma has not been reported in the literature. However, it should be noted as a differential diagnosis for a postoperative mediastinal mass.
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Introduction
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Postoperative chylothorax is reported to be a rare but well-known complication in thoracic surgery [1]. Conservative treatment, such as OK-432 (Picibanil; Chugai Pharmaceutical Co, Ltd, Tokyo, Japan) chemical pleurodesis, is usually effective, but surgical intervention is sometimes necessary in the management of chylothorax [2]. Mediastinal chyloma is stratified into thoracic duct cyst (so-called primary chyloma) and secondary chyloma. Secondary chyloma is usually associated with trauma [3–5]. Allen and colleagues [6] reported a posttraumatic mediastinal chyloma with tracheal compression, necessitating surgical treatment. We described a patient with postoperative mediastinal chyloma located in the upper mediastinum, which developed after a seemingly successful conservative management for postoperative chylothorax. The chyloma compressed the superior vena cava, and surgical intervention was necessary.
A coin lesion was visible in an annual chest roentgenogram of a 69-year-old woman. The patient was a housewife, lived in a rural area, and had never been a smoker. Hypertension was noted as her past history. The right lung tumor was ill-defined, noncalcified, and measured 2.4 by 2.4 cm on the plain x-ray film. Transbronchial biopsy specimen showed a well-differentiated adenocarcinoma. Preoperative workup resulted in a diagnosis of stage IA disease. She underwent right upper lobectomy and systematic mediastinal lymph node dissection on June 26, 1998. Pathologic study of the resected specimen showed a moderately differentiated adenocarcinoma of 3.3 cm in maximum tumor dimension, without metastasis to the locoregional lymph nodes. On the second postoperative day, approximately 300 mL of white turbid fluid was drained through the chest tube, and a postoperative chylothorax was diagnosed. As the chylothorax did not resolve despite a 1-week fast and total parenteral nutrition, 5 KE of OK-432 was administered into the thoracic cavity. Turbid drainage diminished and the chest tube was removed on the 14th postoperative day. Pleural effusion did not accumulate thereafter and the patient was discharged on the 19th postoperative day.
When she visited our outpatient clinic on the 59th postoperative day, a mass in the upper mediastinum was noted on the plain chest roentgenogram. Although the patient remained asymptomatic except slight dyspnea, the size of the mediastinal mass gradually increased. Chest computed tomographic scan on August 30, 1998, showed a low density cystic mass surrounded by a thick and contrast-enhanced capsule in the upper mediastinum (Fig 1). The mass compressed the superior vena cava and trachea. Considering the previous chylothorax, the mass was suspected to be a secondary mediastinal chyloma. As the patient had slight dyspnea and the size of the mass gradually increased, we performed surgical intervention on September 30, 1998. A right thoracotomy revealed a small amount of milky effusion in the thoracic cavity and an elastic mass measuring 5 cm in the upper mediastinum, dorsal to the superior vena cava and ventral to the trachea. The thick capsule was incised and chile spilled out. After the chile was removed, we ligated the thoracic duct immediately cephalad to the diaphragm. The postoperative course was uneventful and the patient was free of any symptoms. The patient was discharged 9 days after the second operation. She is healthy with no signs of mediastinal mass 1 month after operation.
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Fig 1. Chest computed tomographic scan on August 30 showing a low density cystic mass surrounded by a thick and contrast-enhanced capsule in the upper mediastinum. Note that the mass compresses the superior vena cava and trachea.
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Comment
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Mediastinal chyloma has been reported by several investigators [3, 5]. However, most of the chylomas were caused by trauma, and mediastinal chyloma after thoracic surgery has not been reported in the literature. In contrast, postoperative chylothorax has been a well-known complication after thoracic operation. Conservative treatment such as oral intake limitation is effective in most cases of chylothorax, but surgical intervention is sometimes necessary. Intrapleural injection of OK-432, which is a heat- and penicillin-treated lyophilized powder of the Su strain of Streptococcus pyogens A3, has been reported to be effective in managing chylothorax [2]. Recurrence after successful conservative treatment of chylothorax has rarely been reported. In the present case, a very rare complication after thoracic surgery, mediastinal chyloma, developed after a seemingly successful conservative management for postoperative chylothorax. We found a thick capsule containing chylous fluid in the upper mediastinum. Systematic mediastinal lymph node dissection might have caused the postoperative chylothorax. The thick capsule of the chyloma may have been the result of severe inflammatory response caused by the intrapleural injection of OK-432. Therefore, mediastinal chyloma may be a complication of chemical pleurodesis. Although chemical pleurodesis has been reported to be safe and effective [2], the mediastinal chyloma should be noted as its possible complication. Mediastinal chyloma can progress and compress the surrounding intrathoracic structures, as shown in this patient. Surgical drainage and ligation of the thoracic duct seemed effective to manage this condition.
Mediastinal chyloma developed after a major lung resection and systematic lymph node dissection was reported. This complication is rare; however, it should be noted that it can develop after chemical pleurodesis for chylothorax and compress the major vessels or trachea. Plain chest roentgenogram and thoracic computed tomographic scan were useful in the diagnosis. When necessary, surgical drainage and thoracic duct ligation could successfully manage this complication.
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References
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Cerfolio R.J., Allen M.S., Deschamps C., Trastek V.F., Pairolero P.C. Postoperative chylothorax. J Thorac Cardiovasc Surg 1996;112:1361-1366.[Abstract/Free Full Text]
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Shimizu J., Hayashi Y., Oda M., et al. Treatment of postoperative chylothorax by pleurodesis with the streptococcal preparation OK-432. Thorac Cardiovasc Surg 1994;42:233-236.[Medline]
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Sinclair D., Woods E., Saibil E.A., Taylor G.A. "Chyloma". J Trauma 1987;27:567-569.[Medline]
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Tsuchiya R., Sugiura Y., Ogata T., Suemasu K. Thoracic duct cyst of the mediastinum. J Thorac Cardiovasc Surg 1980;79:856-859.[Abstract]
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Higgins C.B., Mulder D.G. Mediastinal chyloma, a roentgenographic sign of chylous fistula. JAMA 1970;211:1188.
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Allen S.J., Koch S.M., Tonnesen A.S., Bowman-Howard M., Khalil K. Tracheal compression caused by traumatic thoracic duct leak. Chest 1994;106:296-297.[Abstract/Free Full Text]
Accepted for publication April 21, 1999.
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Abstract
Introduction
