Hydatid Cyst as a Cause of Pancoast's Syndrome

M. Aghajanzadeh MD, R. Molaie MD, H. Aghajanzadeh MD, K.F. Marandi MD

Departments of Thoracic Surgery and Radiology, Razi Medical Center, Rasht, Iran

Case Presentation

A 20-year-old woman referred with chief complaint of pain and paresthesia in the right shoulder and arm together with reduced size of the right eye. The symptoms began from 8 months previously and had gradually worsened. The patient's past medical and family history were normal and the patient was a non-smoker. In review of the organs, the patient was alert and oriented and no evidence of organ failure was observed. She did not suffer from weight loss, night sweat, cough or sputum production.

The patient presented with ptosis and meiosis of the right eye. The left eye was normal and no lymphadenopathy was found. Thoracic cage, liver and spleen sizes were normal. Mild muscle weakness, atrophy and decreased tendon reflex of the right arm were present.

Laboratory results including eosinophil count, indirect hemagglutinin test and complement fixation test were also normal.

The chest X-ray revealed normal cardiothoracic ratio, normal pulmonary markings and costophrenic angles were clear. Opacity of the right lung apex over the three upper ribs was noted. A local X-ray of the right lung at second rib level was obtained for further evaluation (Fig. 1). The X-ray revealed apical opacity which was associated with complete destruction of the proximal part of the posterior arch of the second rib together with erosive changes of the third rib. A CT scan of the chest (Fig. 2) revealed a soft tissue density in the apex of the lung and destructive changes in the transverse process and body of the second thoracic vertebra together with extra-thoracic tumor expansion.

No sign of pressure effect or tumor extension into the spinal canal was seen. Abdominal sonography was normal. The differential diagnosis included neurogenic tumors, metastasis or possibly an infectious process such as tuberculosis.

With the impression of Pancoast's syndrome, the patient underwent thoracotomy through the third intercostal space in the posterolateral aspect. Cystic masses were seen in the right lung apex, which were aspirated and about 10 cc of clear fluid was obtained. After walling off, the cystic mass was excised. Daughter cysts were observed along with laminated membranes which were irrigated with 0.5% silver nitrate solution. The cyst with surrounding inflammatory tissue were excised. The second thoracic vertebra was involved but the spinal canal was intact.

The patient gradually improved after the operation and the eye and facial problems subsided. Pathologic examination confirmed the diagnosis of hydatid cyst. Control chest X-ray taken one year later showed no apical opacity and mild regeneration of the second rib was observed.

Discussion

Greater awareness of rare diseases and unusual forms of prevalent diseases are of importance in facilitating the recognition of similar cases in the future. Although relatively uncommon in western countries, hydatid cyst with its diverse clinical manifestations, is a prevalent disease in many parts of the world.

The syndrome which is presented here constitutes a very rare presentation of hydatid disease and only a limited number of similar cases have been reported in literature.

Pancoast's syndrome comprises an apical lung mass associated with ipsilateral shoulder and arm pain, muscle atrophy, Horner syndrome and occasional muscle atrophy.¹ This syndrome is often of malignant origin therefore some physicians equate it with a malignant process.^2,3

In one study, 98.6% of cases with this syndrome were due to the four major primary malignant lung tumors and only 1.4% were due to other causes.⁴ These included metastasis,⁵ malignant neurogenic tumors,⁵ acute^6,7 and chronic⁸ infections of lung or chest wall, lymphoma⁹ and hydatid cyst.^1,10-13

Hydatid cyst, a prevalent disease in Iran may infect different body organs. When present in the lungs, the lesion may easily be confused with that of malignant tumors. The mass is usually soft and cystic and neighboring organs are not usually affected.¹⁴ Rarely however, pressure effect and destructive changes to neighboring organs has been observed. Pancoast's syndrome and its features are due to the involvement of brachial plexus and its sympathetic chain secondary to pressure effect or invasion of abnormal tissue.^4,15

Extra-thoracic tumors such as mesothelioma, lymphoma, multiple myeloma, thyroid carcinomas and metastatic tumors can also induce this syndrome. Non-neoplastic causes are very rare and include tuberculosis, bacterial and fungal infections as well as hydatid cyst.^6-8,10,11

Although pulmonary hydatid cyst may be asymptomatic it often manifests itself by cough, pleuritic pain, dyspnea or bloody sputum. Chest X-ray may reveal solitary or multiple cystic masses with the so-called "water lily" sign when ruptured. We found only 7 cases of Pancoast's syndrome of echinoccocal origin in literature; three cases after operation of the cyst or spontaneous¹³ rupture and one subsequent to rupture of the hepatic hydatid cyst into the pleural space.¹⁰

Hydatid cyst as an operable prognostically favorable lesion must be considered in the differential diagnosis of Pancoast's syndrome in the coun-

tries where echinoccocal infection is endemic.

References

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