With a working diagnosis of pleuritis secondary to a malignant versus inflammatory process, medical thoracoscopy was planned to drain the rest of the fluid and to visualize the pleura. She was found to have a well-circumscribed hyperpigmented, soft pleural mass involving the parietal pleura (Fig. 3). There was no associated pulmonary parenchymal abnormality. Multiple biopsies were obtained from this mass that revealed chronic inflammation with reactive mesothelial cells, spindle-shaped myofibroblasts, and some plasma cells with no signs of malignancy.
Considering the entire clinical scenario of the patient, supplemented with histopathologic findings, she was given a final diagnosis of IPT of the pleura secondary to the new-onset systemic lupus erythematosus. She underwent a video-assisted thoracoscopic surgical (VATS) excision of the pleural mass. In addition she was started on high-dose steroids. On a follow-up at 3 months there was near complete resolution of both pleural effusion and proteinuria.
IPT is a rare, non-neoplastic lesion and is a result of unregulated inflammation.2 Current knowledge about prevalence of pulmonary IPT suggests that it is found in 0.7% of lung tumors and 0.04% in general thoracic surgery procedures.5,6 It is a tumor that is predominantly found at younger age with most of the cases reported in patient below 40 years of age without any sex or race bias.3 Pathogenesis of IPT remains unclear with some authors suggesting it to be primarily an inflammatory process, whereas others describing it as a low-grade malignant lesion with a dominant inflammatory component.7,8 The inciting trigger for the inflammation is equally ambiguous with proposed etiologies as metabolic disturbances or dysfunctional cytokine response cascade to pulmonary infections. Many reported cases have had a history of infection with various pathogens such as Mycobacteria, Epstein Barr virus, and Pseudomonas.7,9,10
There have been many documented cases of calcifying fibrous tumors of the pleura that were initially thought to be the end stage of an IPT.14–16 Recently studies have shown that these maybe 2 separate entities based on their immune expression.17,18 In addition there have been reported cases of IPT of the lung presenting with pleural thickening, some of which were found intraoperatively.4,19 To our knowledge there has been no previous recorded case of IPT involving exclusively the pleura.
The clinical presentation of IPT is variable with nonspecific symptoms attributed either to the inflammation in the lesion or the pressure effect.12,13 Patients with IPT of the lung present with cough, chest pain, dyspnea, hemoptysis, and fever. Nail clubbing and hypertropic osteoarthropathy has also been reported.20 Because of the lack of literature on IPT involving only the pleura we will have to extrapolate the information obtained from the cases with pleural involvement from the pulmonary IPT. Exudative pleural effusion rich in cellular elements with pleuritic chest pain may be the most common presentation. Our patient had only mild symptoms that progressed slowly before medical assistance was sought.
Laboratory investigations also may show findings pointing to an ongoing inflammation in the body. There may be elevated C-reactive protein, erythrocyte sedimentation rate, anemia, thrombocytosis, and hypergammaglobulnemia.13 The high levels of double-stranded DNA in our patient was thought to be due to the large size of the tumor and associated inflammation.
Radiologically pleural pseudotumors appear as a solitary or multiple nodular abnormalities.13,21,22 Unlike calcifying fibrous tumor of the pleura where there is extensive calcification easily visualized on imaging, there is scant calcification in the inflammatory myofibroblastic pseudotumor that might get missed.22 IPT of the lung has predilection for the lower lobes and therefore will cause pleural thickening in the adjacent pleura.13 In the case we are reporting we observed the pleural mass to be close to the left lower lobe and in the proximity to the diaphragmatic pleura (Fig. 3).
Semi-invasive diagnostic procedures such as bronchoscopy and percutaneous fine-needle aspiration biopsy have been considered insufficient for the diagnosis of lung IPTs.4,23 Video-assisted thoracoscopic surgery with complete excision of the mass helps in establishing a confirmatory diagnosis.24,25 Our case demonstrates that if there is pleural involvement, primary or secondary, it may be amenable to the diagnosis with less invasive medical thoracoscopy. We were able to get ample amount of tissue specimen through the medical thoracoscopy to help make a histopathologic diagnosis.
As IPT of the lungs do have malignant component with potential to recur, complete surgical resection has been recommended as the best treatment to achieve cure.26,27 Complete tumor excision and tumor size of ≤3 cm are factors associated with a decreased risk of recurrence.28,29 In our patient a VATS-assisted excision of the pleural mass was performed and the patient was started on corticosteroids. The latter treatment decision was based on certain case reports,30,31 which have shown that corticosteroids may have a role in preventing recurrences of IPT. Nonsurgical treatment modalities like radiation, chemotherapy, and steroids can also help manage IPT in patients who are poor surgical candidates or have multiple nodules or unresectable disease.4,32
To the best of our knowledge there are no case reports in the literature of diagnosis of IPT exclusively involving the inflamed pleura. Our case highlights that with the help of medical thoracoscopy we might be able to diagnose this rare pleural pathology before patients are subjected to more invasive procedures.
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