Figure 1
The patient initially presented 14 years previously with a history of pain of the left shoulder. A chest radiograph showed an abnormal shadow with an extrapleural sign located in the left upper lung field. A disease-free course of 9 years followed. Over the past 4 years multiple intrathoracic and extrathoracic recurrences occurred.
Primary intrathoracic extrapulmonary haemangiopericytoma with multiple recurrences
The patient initially presented 14 years previously with a history of pain of the left shoulder. She had no history of shortness of breath, coughing, fever or haemoptysis. A chest radiograph showed an abnormal shadow with an extrapleural sign located in the left upper lung field. A detailed full blood count and biochemical tests showed results within normal range. Chest CT revealed a well-demarcated soft tissue mass in the chest wall adjacent to the second left rib. The diagnosis of haemangiopericytoma was established by percutaneous needle biopsy. The mass was successfully resected and a disease-free course of 9 years followed.
Over the past 4 years multiple intrathoracic recurrences had occurred, as shown in multiple spiral CT examinations, including: soft tissue masses involving the 4th-6th left rib and the 6th-8th right rib, one left epidiaphragmatic pleural soft tissue mass and a pulmonary mass at the left pulmonary ligament. Additionally, extrathoracic recurrences were diagnosed at the sacroiliac joints, the left iliac wing and the diaphysis of the right radius. Histological diagnosis and immunochemical studies were obtained at each stage.
Over the past 4 years multiple intrathoracic recurrences had occurred, as shown in multiple spiral CT examinations, including: soft tissue masses involving the 4th-6th left rib and the 6th-8th right rib, one left epidiaphragmatic pleural soft tissue mass and a pulmonary mass at the left pulmonary ligament. Additionally, extrathoracic recurrences were diagnosed at the sacroiliac joints, the left iliac wing and the diaphysis of the right radius. Histological diagnosis and immunochemical studies were obtained at each stage.
Incidence and location
Hemangiopericytoma is a rare tumor of high vascularity belonging to the group of sarcomas. Stout and Murray first described this entity in 1942 (1). The tumor arises from the capillary pericyte of Zimmermann, which is a contractile cell normally found spiraling in an incomplete layer around the capillaries and postcapillary venules.
It generally presents in middle and late adulthood. Because of its vascular origin, it may be found anywhere in the body. Principal sites of the tumour include lower limb and the retroperitoneal space. Hemangiopericytomas rarely arise in the chest wall. There seems to be a predominance for women in the case of hemangiopericytomas originating in the chest wall (2).
Clinical behaviour
Symptoms depend on the location of the tumour and are mostly due to pressure effects on the surrounding structures. Thoracic hemangiopericytomas may be discovered incidentally, presenting without any symptoms. The rate of recurrence is given as 50%. Adult cases usually follow a benign course but 20–30% of cases behave in malignant fashion. Distant metastases occur via hematogenous route. Local or distant recurrences have been reported to occur at long intervals after the initial diagnosis.
Histological features
The natural history of hemangiopericytoma is associated with cellularity, mitotic activity, necrosis, and hemorrhage. Four or more mitoses per high-power field, foci of necrosis, and increased cellularity are suggestive of malignancy and poor prognosis. The histology of adult hemangiopericytoma usually shows a well demarcated but multinodular mass. Positive reticulin stain is the criterion for the diagnosis of hemangiopericytoma (3). The tumor seems to have a low tendency to infiltrate into surrounding tissue rather than to form a fibrotic capsule against displaced tissue.
Imaging appearance
Hemangiopericytomas, at any location, are difficult to diagnose on the basis of imaging findings alone. Such findings are nonspecific in the majority of cases and may suggest only a soft tissue origin or marked hypervascularity of the tumor. Contrast-enhanced CT scan, angiography, and magnetic resonance imaging can be employed preoperatively, as well as during the follow-up. In a case of an intrathoracic extrapulmonary hemangiopericytoma, cross-section imaging modalities may suggest the diagnosis. A chest radiograph is an essential tool in the diagnostic workup. In the chest radiograph the size and contour of the tumor are initially evaluated, which may vary from a sharply delineated round or lobulated mass, as well as the presence or absence of pleural effusion. The CT findings of a thoracic hemangiopericytoma may include a large, well-circumscribed, lobulated, soft tissue mass with cystic low attenuation zones and speckled calcifications. After intravenous administration of contrast agent, there is enhancement of solid areas or septations (4). CT sometimes shows capsular like appearance, contrast enhancement of the “capsular” margin, without signs of surrounding compression atelectasis. A heterogeneous matrix is usually noted in large tumors. The differential diagnosis includes other soft tissue sarcomas of the lung (i.e. an angiosarcoma, fibrosarcoma, leiomyosarcoma, primary liposarcoma or a Kaposi’s sarcoma in immunocompromised patients), as well as other unusual lung tumors (of vascular origin, i.e. a hemangioendothelioma and sclerosing hemangioma, of other mesenchymal tissue, i.e. solitary fibrous tumor, malignant thoracopulmonary small cell tumor -"Askin" tumor-, or plasma cell granuloma). MRI is the most sensitive instrument to exclude invasion of neighboring structures. It defines the extent of the tumor more clearly and provides better tissue characterization. MRI shows intermediate signals on T1-weighted images and increased signal on T2-weighted images (4). Nevertheless, compared to MRI, CT scan may offer a more detailed report of bone involvement in cases of primary or metastatic hemangiopericytomas that arise from osseous structures. Osseous lesions may reveal lysis, or a honeycomb appearance similar to that of hemangioma. In high-grade malignant hemangiopericytomas more aggressive features of marked osseous expansion are frequently present.
An angiographic study may detect the feeding vessels of this hypervascular tumor. Preoperative embolization has been suggested in cases of very hypervascular tumors, so as to decrease the risk of uncontrollable bleeding and massive blood loss.
As far as recurrences are concerned, CT helps determine the location and features of each new lesion and depicts associated findings, in order to document the extent of disease. Both intrathoracic and extrathoracic recurrences have been discovered many years after the initial diagnosis and long-term follow-up is necessary (5). The CT features of recurrences include soft tissue masses, round or lobulated, with contrast enhancement in solid areas or in septations, and with osseous destruction in cases of osseous involvement.
The radiologic appearance of primary intrathoracic extrapulmonary hemangiopericytoma with multiple intra- and extrathoracic recurrences is rarely cited in current literature. The clinical course of this entity may be long and uneventful unless it involves vital structures and spiral CT may serve as an effective means of recording its progress in sites of recurrence.
Hemangiopericytoma is a rare tumor of high vascularity belonging to the group of sarcomas. Stout and Murray first described this entity in 1942 (1). The tumor arises from the capillary pericyte of Zimmermann, which is a contractile cell normally found spiraling in an incomplete layer around the capillaries and postcapillary venules.
It generally presents in middle and late adulthood. Because of its vascular origin, it may be found anywhere in the body. Principal sites of the tumour include lower limb and the retroperitoneal space. Hemangiopericytomas rarely arise in the chest wall. There seems to be a predominance for women in the case of hemangiopericytomas originating in the chest wall (2).
Clinical behaviour
Symptoms depend on the location of the tumour and are mostly due to pressure effects on the surrounding structures. Thoracic hemangiopericytomas may be discovered incidentally, presenting without any symptoms. The rate of recurrence is given as 50%. Adult cases usually follow a benign course but 20–30% of cases behave in malignant fashion. Distant metastases occur via hematogenous route. Local or distant recurrences have been reported to occur at long intervals after the initial diagnosis.
Histological features
The natural history of hemangiopericytoma is associated with cellularity, mitotic activity, necrosis, and hemorrhage. Four or more mitoses per high-power field, foci of necrosis, and increased cellularity are suggestive of malignancy and poor prognosis. The histology of adult hemangiopericytoma usually shows a well demarcated but multinodular mass. Positive reticulin stain is the criterion for the diagnosis of hemangiopericytoma (3). The tumor seems to have a low tendency to infiltrate into surrounding tissue rather than to form a fibrotic capsule against displaced tissue.
Imaging appearance
Hemangiopericytomas, at any location, are difficult to diagnose on the basis of imaging findings alone. Such findings are nonspecific in the majority of cases and may suggest only a soft tissue origin or marked hypervascularity of the tumor. Contrast-enhanced CT scan, angiography, and magnetic resonance imaging can be employed preoperatively, as well as during the follow-up. In a case of an intrathoracic extrapulmonary hemangiopericytoma, cross-section imaging modalities may suggest the diagnosis. A chest radiograph is an essential tool in the diagnostic workup. In the chest radiograph the size and contour of the tumor are initially evaluated, which may vary from a sharply delineated round or lobulated mass, as well as the presence or absence of pleural effusion. The CT findings of a thoracic hemangiopericytoma may include a large, well-circumscribed, lobulated, soft tissue mass with cystic low attenuation zones and speckled calcifications. After intravenous administration of contrast agent, there is enhancement of solid areas or septations (4). CT sometimes shows capsular like appearance, contrast enhancement of the “capsular” margin, without signs of surrounding compression atelectasis. A heterogeneous matrix is usually noted in large tumors. The differential diagnosis includes other soft tissue sarcomas of the lung (i.e. an angiosarcoma, fibrosarcoma, leiomyosarcoma, primary liposarcoma or a Kaposi’s sarcoma in immunocompromised patients), as well as other unusual lung tumors (of vascular origin, i.e. a hemangioendothelioma and sclerosing hemangioma, of other mesenchymal tissue, i.e. solitary fibrous tumor, malignant thoracopulmonary small cell tumor -"Askin" tumor-, or plasma cell granuloma). MRI is the most sensitive instrument to exclude invasion of neighboring structures. It defines the extent of the tumor more clearly and provides better tissue characterization. MRI shows intermediate signals on T1-weighted images and increased signal on T2-weighted images (4). Nevertheless, compared to MRI, CT scan may offer a more detailed report of bone involvement in cases of primary or metastatic hemangiopericytomas that arise from osseous structures. Osseous lesions may reveal lysis, or a honeycomb appearance similar to that of hemangioma. In high-grade malignant hemangiopericytomas more aggressive features of marked osseous expansion are frequently present.
An angiographic study may detect the feeding vessels of this hypervascular tumor. Preoperative embolization has been suggested in cases of very hypervascular tumors, so as to decrease the risk of uncontrollable bleeding and massive blood loss.
As far as recurrences are concerned, CT helps determine the location and features of each new lesion and depicts associated findings, in order to document the extent of disease. Both intrathoracic and extrathoracic recurrences have been discovered many years after the initial diagnosis and long-term follow-up is necessary (5). The CT features of recurrences include soft tissue masses, round or lobulated, with contrast enhancement in solid areas or in septations, and with osseous destruction in cases of osseous involvement.
The radiologic appearance of primary intrathoracic extrapulmonary hemangiopericytoma with multiple intra- and extrathoracic recurrences is rarely cited in current literature. The clinical course of this entity may be long and uneventful unless it involves vital structures and spiral CT may serve as an effective means of recording its progress in sites of recurrence.
References
[1]
Enzinger FM, Smith BH.
Hemangiopericytoma. An analysis of 106 cases.
Hum Pathol 1976;7:6182. (PMID: 1244311)
[2]
Yanagihara K, Ueno Y, Isobe J, Yoshimi N, Itoh M.
Hemangiopericytoma of the chest wall.
Ann Thorac Surg 1997;63:537-9. (PMID: 9033336)
[3]
Husain AS, Haapaniemi J.
Aspiration biopsy cytology of malignant haemangiopericytoma metastatic to the lung. Cytomorphic and immunocytochemical study of a case.
Acta Cytol 1997;41:1265-8. (PMID: 9990255)
[4]
Kusumoto S, Nakamura R, Mizoguchi N, Ono S, Watanabe K.
Primary intrathoracic extrapulmonary hemangiopericytoma. CT and MR findings.
Clin Imaging 1997;21(1):51-3. (PMID: 9117932)
[5]
Kiefer T, Wertzel H, Freudenberg N, Hasse J.
Long-term survival after repetitive surgery for malignant hemangiopericytoma of the lung with subsequent systemic metastases: case report and review of the literature.
Thorac Cardiovasc Surg 1997; 45:307-309. (PMID: 9477464)
Case information
| URL: | https://eurorad.org/case/2124 |
| DOI: | 10.1594/EURORAD/CASE.2124 |
| ISSN: | 1563-4086 |
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