European Journal of Radiology. 15 ( 1992) 4-6 0 1992 Elsevier Science Publishers B.V. All rights reserved. 0720-048X/92/$05.00
4
EURRAD 00273
Intrapericardial B. Padovani”, “Dipartement
bronchogenic cyst: CT and MR demonstration
P. Hofmanb,
S. Chanaleta,
de Radiologie, hLaboratoire diinatomo-pathologie, Cardiaque,
B. Taillan”, J. Jourdand
and J.-J. Serresa
‘Service de MPdecine Interne (HGpital de Cimiez), dService de Chirurgie
Centre Hospitalier RPgional Nice, H6pital Pasteur, Nice, France
(Received 24 October 1991; accepted after revision 20 December 1991)
Key words: Magnetic resonance imaging, thorax; Computed tomography, thorax; Thorax, bronchogenic cyst; Thorax, pericardium
Bronchogenic cysts account for 40-50x of all congenital cysts of the mediastinum, but intrapericardial localizations are exceptional. To our knowledge, only one case has been investigated by MR to date [ 11. We report a new case of an intrapericardial bronchogenic cyst investigated by CT and MR. Surgery provided the opportunity to confirm the diagnosis and compare imaging data with histologic findings. Case report A 42-year-old woman was hospitalized for an abdominopelvic mass with an inflammatory syndrome and weight loss of 7 kg. Puncture biopsy of the mass demonstrated actinomycosis. A routine chest radiograph revealed increased convexity of the lower right cardiac contour. Thoracic CT scans confirmed the presence of an 8 cm diameter, heterogeneous right paracardiac mass presenting multiple hypodense zones (20 HU) separated by thickened, irregular septa (Fig. la). Transthoracic and transesophageal echocardiography visualized a mass with a heterogeneous echostructure containing fluid-density zones, and confirmed the intrapericardial localization. Thoracic MR examination with Tl-weighted images
(TR 600 ms/TE 20 ms) revealed an 8 x 8 x 10 cm right anterior paracardiac mass lying against the right atrium, the ascending aorta, and the superior vena cava (Fig. lb). Axial scans confirmed the intrapericardial
Correspondence to: Bernard Padovani, M.D. HBpital Pasteur, 30, avenue de la Voie Romaine, 06002 Nice Cedex France.
localization and visualized a small associated pericardial effusion. The signal was heterogeneous, with the presence of well-defined areas of high signal intensity (Fig. lc). No contrast enhancement was observed following I.V. administration of gadolinium. Antibiotic therapy was instituted, and produced marked regression of the abdominopelvic mass and disappearance of the inflammatory syndrome over a two-month period, but the paracardiac mass remained unchanged. At surgery, the intrapericardial location was confirmed and the lesion was resected. Gross examination showed a multilocular mass composed of numerous cysts varying in size from 1 to 3 cm. Examination of the cysts’ contents revealed a mucoid gelatinous substance (Fig. 2). Microscopic examination demonstrated the presence of a pseudostratified, ciliated respiratory epithelium covering smooth muscle tissue and bronchial glands. The histologic diagnosis was a bronchogenic cyst. Discussion Bronchogenic cysts result from separation of an aberrant bud from the tracheobronchial tree between the 26th and 40th days of intrauterine life [2]. Such cysts mainly occur in the lungs or mediastinum. Intrapericardial locations have been reported, but remain exceptional. In a 1974 review of the literature [ 31, only 21 cases were collected. Most of these cysts are discovered during the first two decades, generally in children, and female predominance has been noted. These abnormalities tend to be right-sided, lying between the root of the aorta and the superior vena
b
Fig. 1. (a) CT scan demonstrating the hypodense right paracardiac mass with thick septa (curved arrows); (b) Coronal, Tl-weighted MR image showing the right paracardiac mass with heterogeneous signal intensities (black arrows). (c) Axial, Tl-weighted MR image demonstrating the pericardial effusion (white arrows). The pericardium (white arrowheads) is displaced by the mass. Note the presence of several zones of high signal intensity (black arrows).
cava, and may compress the vessels and the heart [4]. In this localization, the cysts have no connections with the tracheobronchial tree. In our case, the location of this mass adjacent to the right atrium was atypical. Clinical symptoms are variable, and depend on cyst size, location and degree of any vessel and heart compression [ 51. Mediastinal bronchogenic cysts commonly attain large dimensions without causing any clinical symptoms [2], as in our patient.
There are few reports of CT imaging of intrapericardial bronchogenic cysts [ 1,5,6]. Moncada and coworkers [ 51 emphasized the value of CT for confirming the intrapericardial location and determining the lesion’s cystic or solid nature. Other authors [ 7,8] have pointed out that mediastinal bronchogenic cysts often have elevated intracystic densities (up to 130 HU) owing to the presence of mucoid material and a high protein content. In our case, the density was low
b
Fig. 2. Gross appearance: multiple cystic compartments delimited by fibrous septa; clumps of a gelatinous substance (black arrows).
(20 HU) and the appearance of the multilocular mass with thick septa suggested a necrotic tumor rather than a cystic lesion, despite the absence of enhancement after injection of iodinated contrast material. These findings were related to the multilocular nature of the cyst and the presence of considerable intracystic inflammatory changes. MR proved more valuable for confirming the intrapericardial location and for accurately determining the lesion’s relationship with the cardiac cavities and great vessels of the mediastinum. The heterogeneous signal of the mass on Tl-weighted images and existence of an associated pericardial effusion were in favor of a malignant lesion. Pericardial effusions are rarely associated with intrapericardial bronchogenic cysts [ 51; they are more common with malignant tumors and certain benign cystic tumors such as teratomas [5]. Although we did not perform T2-weighted sequences, retrospective signal analysis and comparison with the gross findings proved instructive. The areas of high signal intensity on Tl-weighted sequences corresponded to clumps of gelatinous mucoid material. The high signal, explained by considerable shortening of Tl, was related to the high protein content of these clumps. Similar appearances are seen in cases of intracystic
hemorrhage or presence of fatty material. However, analysis of the CT scans had not revealed any negative, fat density zones. To our knowledge, only one other intrapericardial bronchogenic cyst has been investigated with MR [ 11. In that report, the cyst presented a homogeneous, high signal intensity on Tl-weighted images, and had a high CT density (40-60 HU). These findings allowed the authors to rule out a solid lesion, and suggested either a cyst containing protein-rich fluid or a hemorrhagic cyst. In our patient, non-enhancement with contrast was the major clue to exclude a malignant solid lesion and was seen with both CT and MR. Our findings emphasize the value of a combination of CT and MR for tissue characterization of this type of tumor. In particular, preoperative diagnosis could have been improved by recognition of the gelatinous mucoid material secreted by the ciliated respiratory epithelium. References Konig R, Herold U. Kernspintomographischer Nachweis einen mediastinalen bronchogenen Zyste. Radiologe 1986; 26: 464-466. Fraser RG, Pare JAP, Pare PD, Fraser RS, Genereux G.P. Diagnosis of disease of the chest. 3rd edn. Saunders, PA, USA 1989; 695-773. Deenadayalu RP, Tuuri D, Dewall RA, Johnson FG. Intrapericardial teratoma and bronchogenic cyst. Review of literature and report of successful surgery in infant with intrapericardiac teratoma. J Thorac Cardiovasc Surg 1974; 67: 945-995. Dabbs CH, Berg R Jr, Peirce EC II. Intrapericardial bronchogenie cysts; report of two cases and probable embryologic explanation. J Thorac Surg 1957; 34: 718-735. Moncada R, Baliga K, Moguillansky SJ, Subramanian R, Demos TC, Losada C, Bianchi G, Ow EP. CT diagnosis of congenital intra-pericardial masses. J Comput Assist Tomogr 1985; 9: 56-59. Shimizu M, Takeda R, Mifune JL, Tanaka T. Echocardiographic features of intrapericardial bronchogenic cyst. Cardiology 1990; 77: 322-326. Nakata H, Nakayama C, Kimoto T, Nakayama T, Tsukamoto Y, Nobe T, Suzuki H. Computed tomography of mediastinal bronchogenic cysts. J Comput Assist Tomogr 1982; 6: 733-738. Mendelson DS, Rose JS, Efremidis SC, Kirschner PA, Cohen BA. Bronchogenic cysts with high CT numbers. AJR 1983; 140: 463-465.
4
EURRAD 00273
Intrapericardial B. Padovani”, “Dipartement
bronchogenic cyst: CT and MR demonstration
P. Hofmanb,
S. Chanaleta,
de Radiologie, hLaboratoire diinatomo-pathologie, Cardiaque,
B. Taillan”, J. Jourdand
and J.-J. Serresa
‘Service de MPdecine Interne (HGpital de Cimiez), dService de Chirurgie
Centre Hospitalier RPgional Nice, H6pital Pasteur, Nice, France
(Received 24 October 1991; accepted after revision 20 December 1991)
Key words: Magnetic resonance imaging, thorax; Computed tomography, thorax; Thorax, bronchogenic cyst; Thorax, pericardium
Bronchogenic cysts account for 40-50x of all congenital cysts of the mediastinum, but intrapericardial localizations are exceptional. To our knowledge, only one case has been investigated by MR to date [ 11. We report a new case of an intrapericardial bronchogenic cyst investigated by CT and MR. Surgery provided the opportunity to confirm the diagnosis and compare imaging data with histologic findings. Case report A 42-year-old woman was hospitalized for an abdominopelvic mass with an inflammatory syndrome and weight loss of 7 kg. Puncture biopsy of the mass demonstrated actinomycosis. A routine chest radiograph revealed increased convexity of the lower right cardiac contour. Thoracic CT scans confirmed the presence of an 8 cm diameter, heterogeneous right paracardiac mass presenting multiple hypodense zones (20 HU) separated by thickened, irregular septa (Fig. la). Transthoracic and transesophageal echocardiography visualized a mass with a heterogeneous echostructure containing fluid-density zones, and confirmed the intrapericardial localization. Thoracic MR examination with Tl-weighted images
(TR 600 ms/TE 20 ms) revealed an 8 x 8 x 10 cm right anterior paracardiac mass lying against the right atrium, the ascending aorta, and the superior vena cava (Fig. lb). Axial scans confirmed the intrapericardial
Correspondence to: Bernard Padovani, M.D. HBpital Pasteur, 30, avenue de la Voie Romaine, 06002 Nice Cedex France.
localization and visualized a small associated pericardial effusion. The signal was heterogeneous, with the presence of well-defined areas of high signal intensity (Fig. lc). No contrast enhancement was observed following I.V. administration of gadolinium. Antibiotic therapy was instituted, and produced marked regression of the abdominopelvic mass and disappearance of the inflammatory syndrome over a two-month period, but the paracardiac mass remained unchanged. At surgery, the intrapericardial location was confirmed and the lesion was resected. Gross examination showed a multilocular mass composed of numerous cysts varying in size from 1 to 3 cm. Examination of the cysts’ contents revealed a mucoid gelatinous substance (Fig. 2). Microscopic examination demonstrated the presence of a pseudostratified, ciliated respiratory epithelium covering smooth muscle tissue and bronchial glands. The histologic diagnosis was a bronchogenic cyst. Discussion Bronchogenic cysts result from separation of an aberrant bud from the tracheobronchial tree between the 26th and 40th days of intrauterine life [2]. Such cysts mainly occur in the lungs or mediastinum. Intrapericardial locations have been reported, but remain exceptional. In a 1974 review of the literature [ 31, only 21 cases were collected. Most of these cysts are discovered during the first two decades, generally in children, and female predominance has been noted. These abnormalities tend to be right-sided, lying between the root of the aorta and the superior vena
b
Fig. 1. (a) CT scan demonstrating the hypodense right paracardiac mass with thick septa (curved arrows); (b) Coronal, Tl-weighted MR image showing the right paracardiac mass with heterogeneous signal intensities (black arrows). (c) Axial, Tl-weighted MR image demonstrating the pericardial effusion (white arrows). The pericardium (white arrowheads) is displaced by the mass. Note the presence of several zones of high signal intensity (black arrows).
cava, and may compress the vessels and the heart [4]. In this localization, the cysts have no connections with the tracheobronchial tree. In our case, the location of this mass adjacent to the right atrium was atypical. Clinical symptoms are variable, and depend on cyst size, location and degree of any vessel and heart compression [ 51. Mediastinal bronchogenic cysts commonly attain large dimensions without causing any clinical symptoms [2], as in our patient.
There are few reports of CT imaging of intrapericardial bronchogenic cysts [ 1,5,6]. Moncada and coworkers [ 51 emphasized the value of CT for confirming the intrapericardial location and determining the lesion’s cystic or solid nature. Other authors [ 7,8] have pointed out that mediastinal bronchogenic cysts often have elevated intracystic densities (up to 130 HU) owing to the presence of mucoid material and a high protein content. In our case, the density was low
b
Fig. 2. Gross appearance: multiple cystic compartments delimited by fibrous septa; clumps of a gelatinous substance (black arrows).
(20 HU) and the appearance of the multilocular mass with thick septa suggested a necrotic tumor rather than a cystic lesion, despite the absence of enhancement after injection of iodinated contrast material. These findings were related to the multilocular nature of the cyst and the presence of considerable intracystic inflammatory changes. MR proved more valuable for confirming the intrapericardial location and for accurately determining the lesion’s relationship with the cardiac cavities and great vessels of the mediastinum. The heterogeneous signal of the mass on Tl-weighted images and existence of an associated pericardial effusion were in favor of a malignant lesion. Pericardial effusions are rarely associated with intrapericardial bronchogenic cysts [ 51; they are more common with malignant tumors and certain benign cystic tumors such as teratomas [5]. Although we did not perform T2-weighted sequences, retrospective signal analysis and comparison with the gross findings proved instructive. The areas of high signal intensity on Tl-weighted sequences corresponded to clumps of gelatinous mucoid material. The high signal, explained by considerable shortening of Tl, was related to the high protein content of these clumps. Similar appearances are seen in cases of intracystic
hemorrhage or presence of fatty material. However, analysis of the CT scans had not revealed any negative, fat density zones. To our knowledge, only one other intrapericardial bronchogenic cyst has been investigated with MR [ 11. In that report, the cyst presented a homogeneous, high signal intensity on Tl-weighted images, and had a high CT density (40-60 HU). These findings allowed the authors to rule out a solid lesion, and suggested either a cyst containing protein-rich fluid or a hemorrhagic cyst. In our patient, non-enhancement with contrast was the major clue to exclude a malignant solid lesion and was seen with both CT and MR. Our findings emphasize the value of a combination of CT and MR for tissue characterization of this type of tumor. In particular, preoperative diagnosis could have been improved by recognition of the gelatinous mucoid material secreted by the ciliated respiratory epithelium. References Konig R, Herold U. Kernspintomographischer Nachweis einen mediastinalen bronchogenen Zyste. Radiologe 1986; 26: 464-466. Fraser RG, Pare JAP, Pare PD, Fraser RS, Genereux G.P. Diagnosis of disease of the chest. 3rd edn. Saunders, PA, USA 1989; 695-773. Deenadayalu RP, Tuuri D, Dewall RA, Johnson FG. Intrapericardial teratoma and bronchogenic cyst. Review of literature and report of successful surgery in infant with intrapericardiac teratoma. J Thorac Cardiovasc Surg 1974; 67: 945-995. Dabbs CH, Berg R Jr, Peirce EC II. Intrapericardial bronchogenie cysts; report of two cases and probable embryologic explanation. J Thorac Surg 1957; 34: 718-735. Moncada R, Baliga K, Moguillansky SJ, Subramanian R, Demos TC, Losada C, Bianchi G, Ow EP. CT diagnosis of congenital intra-pericardial masses. J Comput Assist Tomogr 1985; 9: 56-59. Shimizu M, Takeda R, Mifune JL, Tanaka T. Echocardiographic features of intrapericardial bronchogenic cyst. Cardiology 1990; 77: 322-326. Nakata H, Nakayama C, Kimoto T, Nakayama T, Tsukamoto Y, Nobe T, Suzuki H. Computed tomography of mediastinal bronchogenic cysts. J Comput Assist Tomogr 1982; 6: 733-738. Mendelson DS, Rose JS, Efremidis SC, Kirschner PA, Cohen BA. Bronchogenic cysts with high CT numbers. AJR 1983; 140: 463-465.
