Diagnostic and therapeutic challenges of a large pleural inflammatory myofibroblastic tumor

Abstract

We report a 48-year-old woman with a pleural pseudoneoplasm requiring different diagnostic and therapeutic strategies. After initial presentation with increasing dyspnoea, temperature, dry cough, and interscapular pain diagnostic processing showed a large mediastinal mass with marked pleural effusion and high metabolic activity in the 18F-FDG-PET/CT. Extensive CT-guided biopsy of the tumor reaching from the visceral pleura into the right upper lobe revealed no malignancy, but a marked inflammatory tissue reaction containing foam cells. Initial empiric antibiotic therapy was temporarily successful. However, in the further course the mass relapsed and was resistant to antibiotics and a corticosteroid trial. With the working hypothesis of an inflammatory myofibroblastic tumor the patient underwent surgical tumor resection, finally confirming the suspected diagnosis. Due to residual disease intravenous immunoglobulins were administered leading to sustained response. This case with a pleural localisation of a large inflammatory pseudotumor with responsiveness to immunomodulation after incomplete resection extends the reported spectrum of thoracopulmonary manifestations of this rare entity.

Figure 1

Anteroposterior chest radiograph showing a large homogenous opacity right paramediastinal and right side pleural effusion. (a) Initial presentation. (b) Response to treatment with moxifloxacin four weeks after initial presentation.

Figure 2

Computed tomography (CT) scan of the chest with CT-guided needle biopsy of a right paramediastinal tumor. In total 10 biopsies were taken from the 8.4 cm large mass.

Figure 3

18-FDG PET-CT scan with high FDG uptake in a right paramediastinal mass (a). Postoperative scans showing residual FDG uptake one month after surgery (b), a decrease in intensity after immunomodulation with intravenous immunoglobulins 4 months later (c), and sustained response at one-year followup (d).

Figure 4

Tumor biopsy showing a dense highly vasculated mixed inflammatory infiltration ((a); H&E, 40x), composed of macrophages with foamy cytoplasm, so called histiocytes, some lymphocytes and plasma cells ((b); H&E, 400x).