|Year : 2018 | Volume
| Issue : 1 | Page : 68-70
Pleural mass imaging - A quick primer
Raajit Chanana, Vijay Patil, Vanita Noronha, Amit Joshi, Kumar Prabhash
Department of Medical Oncology, Tata Memorial Hospital, Mumbai, Maharashtra, India
|Date of Web Publication||12-Dec-2018|
Dr. Raajit Chanana
91, Pocket B Sukhdev Vihar, New Delhi - 110 025
Source of Support: None, Conflict of Interest: None
A 35-year-old female patient with no comorbidities and no history of addictions presented with a 2 week history of intermittent right-sided chest pain without any associated symptoms. On local examination, there was dullness over the right infrascapular and right infra-axillary area along with decreased breath sounds over the corresponding areas. Computed tomography scan revealed a well-defined lobulated heterogeneously enhancing pleural-based mass. What is the most likely diagnosis?
Keywords: Solitary fibrous tumors, pleural mass, pleural tumors
|How to cite this article:|
Chanana R, Patil V, Noronha V, Joshi A, Prabhash K. Pleural mass imaging - A quick primer. Cancer Res Stat Treat 2018;1:68-70
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient has given his/her consent for his/her images and other clinical information to be reported in the journal. The patient understands that his/her name and other identifying information will not be published and due efforts will be made to conceal his/her identity, but that anonymity cannot be guaranteed.
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| Introduction|| |
The pleura can be involved by various benign, malignant, and tumor-like conditions. These conditions are differentiated radiologically on the basis of laterality, presence, or absence of calcification and associated conditions such as pleural effusion and rib destruction. The most common tumor-like condition involving the pleura is pleural thickening. Differentiation of a pleural-based mass from pulmonary and extra-pleural neoplasms is crucial in making treatment decisions. Radiological assessment of pleural tumors requires a basic understanding of the pleural anatomy. The pleura is a serous membrane made of mesothelial cells and divided into parietal pleura and visceral pleura, with a normal thickness of 0.2–0.44 mm. Under normal circumstances, the pleura is not separately seen, unless demarcated by fluid, air, or fascia. Pulmonary masses usually have acute angles with the chest wall and are centered in the lung. A pleural mass forms an obtuse angle with the chest wall, displaces the pulmonary vasculature and may show incomplete border sign (only a portion of the margin of mass can be seen on the chest radiograph). While pleural masses usually do not cause erosion of ribs or displace the extrapleural fat outward, extrapleural masses (fat, ribs or intercostal muscles, and neurovascular bundle) usually displace the extrapleural fat inward.
| Solitary Fibrous Tumor|| |
Solitary fibrous tumor (SFT) comprises a histologic spectrum of rare metastasizing fibroblastic mesenchymal tumors. It was first described in 1931 by Klempere and Robin in a patient with a distinctive pleural lesion as a mesothelial tumor. SFT is divided into two entities, pleural and extrapleural. Pleural SFT is also known as localized fibrous tumor and develops in the age group of 40 to 60 years with a female predominance. Extra pleural SFTs are observed in middle-aged adults (median age 50 years) and affect both sexes equally (male:female = 1:1.2). SFT is now recognized to occur anywhere in the body, including soft tissues and viscera with a predilection for body cavity sites such as pleura, peritoneum, and meninges. SFTs are rare tumors accounting for <2% of soft tissue tumors. Pleural SFTs account for <5% of all tumors arising from the pleura. Majority of SFTs behave in an indolent fashion and do not recur locally or distantly.
At presentation, approximately 40%–60% of patients have nonspecific pulmonary symptoms like cough, shortness of breath, or chest pain. It may be detected incidentally in asymptomatic individuals at the time of the chest imaging or during the evaluation of an unrelated condition. Large tumors that are not discovered incidentally may cause symptoms due to mechanical compression. Approximately 20% of pleuropulmonary SFT may be associated with clubbing, hypertrophic osteoarthropathy (Pierre–Marie–Bamberger syndrome), and in <5% of patients, it may be associated with hypoglycemia (Doege–Potter syndrome).
Radiologically, on cross-sectional imaging, findings are similar to those of other soft-tissue tumors, and there are no pathognomonic features that are specific for this tumor. SFTs usually appear as well-circumscribed masses. In the contrast-enhanced computed tomography (CECT) image, [Figure 1] and [Figure 2], the mass appears to be a pleural-based neoplasm with areas of necrosis, hemorrhage, and cystic changes with or without calcification.
The patient described above underwent a CT-guided biopsy of the pleural lesion. Microscopically, the lesion had atypical spindled cells, arranged haphazardly within the stroma, characteristically referred as to as a patternless pattern (less and more cellular areas alternate), on a background of necrosis. On immunohistochemistry (IHC), the tumor expressed CD34, Bcl2, CD99, and vimentin, in the absence of actin, desmin, S100 protein or epithelial membrane antigen. The final diagnosis of malignant SFT was made. Recently, IHC demonstration of strong nuclear expression of signal transducer and activator of transcription 6 (STAT6) has been shown to be a highly sensitive and specific marker for SFT., SFTs have been classified as benign or malignant based on histologic demonstration of any one or more of the following features-mitotic activity (>3 mitotic figures per 10 high-power field), presence of necrosis or hemorrhage, large tumor size, increased cellularity, nuclear pleomorphism, stromal, or vascular invasion. Anaplastic or dedifferentiated SFT represents an aggressive variant of SFT associated with rapid progression.
SFTs of all sites are characterized by a recurrent inversion of the long arm of chromosome 12 (12q13). This inversion results in fusion of two genes, nerve growth factor-inducible A gene-NGFI-A binding protein 2 and STAT6.
Management of SFTs depends on the site, presence, or absence of symptoms and extent of spread. Localized pleural SFTs generally are managed by wedge resection. However, in case of large sessile tumors and those with ipsilateral intrapleural metastases, a lobectomy, pneumonectomy or a chest wall or diaphragm resection may be required. There are no data to support the use of adjuvant radiation and chemotherapy for completely resected SFT.
Our patient had symptomatic metastatic disease at presentation. Optimal management for unresectable or metastatic SFT is not established. Based on a retrospective review, she was started on ifosfamide and adriamycin. After 6 cycles of chemotherapy, she had stable disease and has been kept on follow-up.
| Differential Diagnosis of Pleural Solitary Fibrous Tumors|| |
Radiologically, focal tumor-like conditions such as loculated pleural effusion and extrapleural hematoma causing a pleural pseudotumor can be considered as differential diagnoses.
Mesothelioma is a highly malignant and locally aggressive tumor seen in the sixth or seventh decade of life. On imaging, diffuse nodular pleural thickening, pleural plaques, and pleural effusion are usually seen. Typically, pleural plaque is seen adjacent to ribs, involving sixth to ninth ribs.
Both Hodgkin and non Hodgkin lymphoma can involve the pleura. Imaging features such as effusion, pleural nodules, focal, or diffuse pleural thickening with homogeneous contrast enhancement along with mediastinal and hilar lymphadenopathy may be seen.
Pleural metastasis from lung, breast, etc., are commonly associated with pleural effusion. Diffuse or focal nodular pleural thickening may be seen.
Askin tumor is an aggressive malignant tumor of primitive neuroectodermal origin. On imaging, unilateral involvement is generally seen in the form of nodular pleural thickening. Infiltration into the chest wall, mediastinum, and sympathetic chain is pathognomonic.
Pleural lipoma is one of the most common benign pleural conditions which is detected incidentally. On CT, lipoma shows fat density and no contrast enhancement. The presence of enhancing septa within the mass suggests liposarcoma. Other rare pathologies of the pleura include epithelioid hemangioendothelioma, Castleman Disease, sarcomas, malignant fibrous histiocytoma, leukemic infiltration, and extraskeletal osteosarcoma.
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[Figure 1], [Figure 2]