European Journal of Radiology, 10 (1990) 62-64 Elsevier
62
EURRAD
00005
Unilateral hilar enlargement and oligemic lung secondary to mediastinal hydatidosis T. Franquet ‘, E. Gonzalez-Moya2, M.V. Acha2 and F.J. Jimenez’ Departments of ‘Radiology and 2Medicine (Pulmonary Division),Hospital ‘Virgen de1 Camino’, Pamplona, Spain (Accepted
Key words: Chest, hydatidosis;
20 September
Mediastinum,
Introduction Hydatid disease is a parasite infestation caused by the larval stage of the tapeworm Echinococcus. Two pathogenic species can be differentiated: E. granulosus (the most frequently observed) and E. multilocularik. Liver and lung are the two most common parasitized organs [l-3]. Mediastinal involvement by hydatid disease is extremely rare and only sporadic cases have been previously reported [4-61. A patient with mediastinal hydatidosis is described who initially presented with unilateral hilar enlargement and oligemic right lung secondary to hydatid vascular invasion. Case report A 25year-old woman frequently exposed to dogs was admitted to the hospital with a 15 day history of cough, mild hemoptysis and low grade fever. Ten days prior to admission she vomited bright red blood mixed with a fragmented white material characteristic of hydatid vomica. On admission the body temperature was 38 “C and physical examination revealed left basilar r-ales. The remainder of the examination was unremarkable. Chest X-ray films and linear tomography revealed unilateral hilar enlargement in association with an oligemic right lung (Fig. 1). Non-contrastenhanced CT showed some disparity in the degree of pulmonary vascular&y between both lungs. A multiloculated cystic mass involving right hilum and mediastinum at the pre-carinal level was demonstrated. After Address for reprints: T. Franquet, M.D., Department of Radiology, Hospital ‘Virgen de1 Camino’, c/ Irunlarrea s/n, 31008 Pamplona, Spain. 0720-048X/90/$03.50
0 1990 Elsevier Science Publishers
1989)
hydatidosis;
Hydatidosis,
mediastinum
intravenous contrast administration, a marked narrowing of the right pulmonary artery was observed (Fig. 2). Laboratory findings at this time revealed a white blood count of 9.550/mm3, with 3.8% eosinophils, hemoglobin level of 12.6, normal platelet count and sedimentation rate of 110 mm/h. Results of serologic tests for hydatidosis were positive, demonstrating high levels of specific antibody by indirect hemagglutination (l/163840) and the presence of the arc 5 of Capron on immunoelectrophoresis. Bronchoscopic examination showed a partially obstructed intermediary bronchus and the presence of white material in the bronchial tree highly characteristic of fragmented hydatid membranes. It was very difficult to remove this material by suction; however, bronchial aspirate demonstrated the presence of both hydatid membranes and scolices. With the diagnosis of mediastinal hydatidosis with hilar extension a surgical resection was indicated. However, the subsequent hospital course was complicated by fatal hemoptysis. Discussion Mediastinal involvement in hydatid disease is extremely rare and only sporadic cases have been reported [4,6]. The disease has the capacity to affect almost all mediastinal structures. The signs and symptoms in mediastinal echinococcosis are non-specific; however, pressure symptoms, secondary infection, rupture and anaphylactic shock may occur. Hydatid cysts arising in the posterior mediastinum may produce pain from bone erosion, those in the anterior mediastinum may cause dyspnea from tracheal compression and the rare involvement of the middle mediastinum may cause severe
B.V. (Biomedical
Division)
63
Fig. 1. (a) Posteroanterior chest roentgenogram showing unilateral hilar mass and oligemic right lung. (b) Tomograph showing diminished vasculature of right lung. A polilobulated right hilar mass and a subtle infiltrate at left lower lobe are also visible.
complications due to compression and/or erosion of great vessels and bronchi. Hydatid cyst invades bronchial walls and may rupture into the airway lumen. When bronchial communication exists, the complaint of chest pain, cough, fever and acute hypersensitivity may develop. Fragments of hydatid membranes and other intracystic material expelled into the bronchial tree may be bronchoscopically observed in a small number of patients. These bronchoscopic fmdings usually provide the clue to diagnosis of such an entity [7]. Aggressive invasion of vascular structures such as bronchial and pulmonary arteries may cause massive hemoptysis and hemorrhage; the direct passage of hydatid material into the vascular bed may produce a severe anaphylactic reaction. It should be noted that the
intravascular presence of this immunogenic material is responsible for the extremely high level of specific antibodies observed in our case. Unilateral pulmonary oligemia associated with hilar enlargement may be produced by compression or obstruction of a pulmonary artery by a contiguous process. To our knowledge, this is the first case in which an unilateral hilar enlargement associated with an oligemic lung is produced by hydatid mediastinal involvement. Before the development of cross-sectional imaging, radiographic evaluation of mediastinal lesions was limited to plain films. At present, CT represents the most accurate method of evaluating mediastinal disorders. CT can easily distinguish cystic from solid masses providing additional information on mediastinal involvement.
Fig. 2. (a) Pre-contrast CT scan showing a hypodense mediastinai multi-septated mass with hilar extension (arrow). (b) Post-contrast CT scan at the same level shows encassement of the right pulmonary artery and stenosis of the intermediary bronchus (arrowheads).
64
The treatment of hydatid disease is primarily surgical, although treatment with mebendazole has been shown to be useful in a previously reported case [ 51. Surgical resection of complicated cases is said to be technically very difficult, but remains the only effective treatment in such patients. In summary, although mediastinal involvement by hydatid disease is extremely rare, chest physicians and radiologists should include this entity in the differential diagnosis of unilateral pulmonary oligemia in association with hilar enlargement. References 1 Balikian JP, Mudarris FF. Hydatid disease of the lungs. A roentgenologic study of 50 cases. AJR 1974; 122: 692-707.
2 Beggs I. Review. The radiology of hydatid disease. AJR 1985; 639-648. 3 De Diego JC, Lecumberri FJ, Franquet T, Ostiz S. Computed tomography in hepatic echinococcosis. AJR 1982; 139: 699-702. 4 Rakower J, Milwidsky H. Primary mediastinal echinococcosis. Am J Med 1960; 29: 73-83. 5 Oppermann HC, Appell RG, Bostel F, Van Kaick, Wahn V. Mediastinal hydatid disease in childhood: CT documentation of response to treatment with mebendazole. J Comput Assist Tomogr 1982; 6: 175-176. 6 Desai MB. Mediastinal multivesicular hydatid cyst (letter). AJR 1988; 151: 203. 7 McPhail JL, Arora TS. Intrathoracic hydatic disease. Chest 1967; 52; 772-781. 8 Chemtai AK, Bowry TR, Ahmad Z. Evaluation of five immunodiagnostic techniques in echinococcosis patients. Bull WHO 1981; 59: 767-772.
62
EURRAD
00005
Unilateral hilar enlargement and oligemic lung secondary to mediastinal hydatidosis T. Franquet ‘, E. Gonzalez-Moya2, M.V. Acha2 and F.J. Jimenez’ Departments of ‘Radiology and 2Medicine (Pulmonary Division),Hospital ‘Virgen de1 Camino’, Pamplona, Spain (Accepted
Key words: Chest, hydatidosis;
20 September
Mediastinum,
Introduction Hydatid disease is a parasite infestation caused by the larval stage of the tapeworm Echinococcus. Two pathogenic species can be differentiated: E. granulosus (the most frequently observed) and E. multilocularik. Liver and lung are the two most common parasitized organs [l-3]. Mediastinal involvement by hydatid disease is extremely rare and only sporadic cases have been previously reported [4-61. A patient with mediastinal hydatidosis is described who initially presented with unilateral hilar enlargement and oligemic right lung secondary to hydatid vascular invasion. Case report A 25year-old woman frequently exposed to dogs was admitted to the hospital with a 15 day history of cough, mild hemoptysis and low grade fever. Ten days prior to admission she vomited bright red blood mixed with a fragmented white material characteristic of hydatid vomica. On admission the body temperature was 38 “C and physical examination revealed left basilar r-ales. The remainder of the examination was unremarkable. Chest X-ray films and linear tomography revealed unilateral hilar enlargement in association with an oligemic right lung (Fig. 1). Non-contrastenhanced CT showed some disparity in the degree of pulmonary vascular&y between both lungs. A multiloculated cystic mass involving right hilum and mediastinum at the pre-carinal level was demonstrated. After Address for reprints: T. Franquet, M.D., Department of Radiology, Hospital ‘Virgen de1 Camino’, c/ Irunlarrea s/n, 31008 Pamplona, Spain. 0720-048X/90/$03.50
0 1990 Elsevier Science Publishers
1989)
hydatidosis;
Hydatidosis,
mediastinum
intravenous contrast administration, a marked narrowing of the right pulmonary artery was observed (Fig. 2). Laboratory findings at this time revealed a white blood count of 9.550/mm3, with 3.8% eosinophils, hemoglobin level of 12.6, normal platelet count and sedimentation rate of 110 mm/h. Results of serologic tests for hydatidosis were positive, demonstrating high levels of specific antibody by indirect hemagglutination (l/163840) and the presence of the arc 5 of Capron on immunoelectrophoresis. Bronchoscopic examination showed a partially obstructed intermediary bronchus and the presence of white material in the bronchial tree highly characteristic of fragmented hydatid membranes. It was very difficult to remove this material by suction; however, bronchial aspirate demonstrated the presence of both hydatid membranes and scolices. With the diagnosis of mediastinal hydatidosis with hilar extension a surgical resection was indicated. However, the subsequent hospital course was complicated by fatal hemoptysis. Discussion Mediastinal involvement in hydatid disease is extremely rare and only sporadic cases have been reported [4,6]. The disease has the capacity to affect almost all mediastinal structures. The signs and symptoms in mediastinal echinococcosis are non-specific; however, pressure symptoms, secondary infection, rupture and anaphylactic shock may occur. Hydatid cysts arising in the posterior mediastinum may produce pain from bone erosion, those in the anterior mediastinum may cause dyspnea from tracheal compression and the rare involvement of the middle mediastinum may cause severe
B.V. (Biomedical
Division)
63
Fig. 1. (a) Posteroanterior chest roentgenogram showing unilateral hilar mass and oligemic right lung. (b) Tomograph showing diminished vasculature of right lung. A polilobulated right hilar mass and a subtle infiltrate at left lower lobe are also visible.
complications due to compression and/or erosion of great vessels and bronchi. Hydatid cyst invades bronchial walls and may rupture into the airway lumen. When bronchial communication exists, the complaint of chest pain, cough, fever and acute hypersensitivity may develop. Fragments of hydatid membranes and other intracystic material expelled into the bronchial tree may be bronchoscopically observed in a small number of patients. These bronchoscopic fmdings usually provide the clue to diagnosis of such an entity [7]. Aggressive invasion of vascular structures such as bronchial and pulmonary arteries may cause massive hemoptysis and hemorrhage; the direct passage of hydatid material into the vascular bed may produce a severe anaphylactic reaction. It should be noted that the
intravascular presence of this immunogenic material is responsible for the extremely high level of specific antibodies observed in our case. Unilateral pulmonary oligemia associated with hilar enlargement may be produced by compression or obstruction of a pulmonary artery by a contiguous process. To our knowledge, this is the first case in which an unilateral hilar enlargement associated with an oligemic lung is produced by hydatid mediastinal involvement. Before the development of cross-sectional imaging, radiographic evaluation of mediastinal lesions was limited to plain films. At present, CT represents the most accurate method of evaluating mediastinal disorders. CT can easily distinguish cystic from solid masses providing additional information on mediastinal involvement.
Fig. 2. (a) Pre-contrast CT scan showing a hypodense mediastinai multi-septated mass with hilar extension (arrow). (b) Post-contrast CT scan at the same level shows encassement of the right pulmonary artery and stenosis of the intermediary bronchus (arrowheads).
64
The treatment of hydatid disease is primarily surgical, although treatment with mebendazole has been shown to be useful in a previously reported case [ 51. Surgical resection of complicated cases is said to be technically very difficult, but remains the only effective treatment in such patients. In summary, although mediastinal involvement by hydatid disease is extremely rare, chest physicians and radiologists should include this entity in the differential diagnosis of unilateral pulmonary oligemia in association with hilar enlargement. References 1 Balikian JP, Mudarris FF. Hydatid disease of the lungs. A roentgenologic study of 50 cases. AJR 1974; 122: 692-707.
2 Beggs I. Review. The radiology of hydatid disease. AJR 1985; 639-648. 3 De Diego JC, Lecumberri FJ, Franquet T, Ostiz S. Computed tomography in hepatic echinococcosis. AJR 1982; 139: 699-702. 4 Rakower J, Milwidsky H. Primary mediastinal echinococcosis. Am J Med 1960; 29: 73-83. 5 Oppermann HC, Appell RG, Bostel F, Van Kaick, Wahn V. Mediastinal hydatid disease in childhood: CT documentation of response to treatment with mebendazole. J Comput Assist Tomogr 1982; 6: 175-176. 6 Desai MB. Mediastinal multivesicular hydatid cyst (letter). AJR 1988; 151: 203. 7 McPhail JL, Arora TS. Intrathoracic hydatic disease. Chest 1967; 52; 772-781. 8 Chemtai AK, Bowry TR, Ahmad Z. Evaluation of five immunodiagnostic techniques in echinococcosis patients. Bull WHO 1981; 59: 767-772.
