A 21-year-old female was admitted to our hospital after 3 weeks of marked general symptoms (asthenia, hyporexia and weight loss of 5 kg) accompanied by left chest pain, low-grade fever and shortness of breath on exertion. The patient had no known toxic habits and no significant medical or family history. On clinical examination, the patient was hemodynamically stable and apyrexic, with an oxygen saturation of 93% while inspiring room air. Auscultation of the chest revealed inaudible breath sounds in the left thorax. The remaining findings from general physical and systemic examinations were essentially normal. Initial investigations revealed a hemoglobin level of 11.6 gm/dL, a white cell count of 13,680/muL with 80% neutrophils, and a normal platelet count. The patient's serum lactate dehydrogenase (LDH) was 420 U/L. The remaining biochemical parameters were essentially normal. An enzyme-linked immunosorbent assay (ELISA) for human immunodeficiency virus (HIV) was non-reactive. A chest X-ray (Fig. 1) revealed a large left pleural effusion.
A diagnostic thoracentesis was performed, and analysis of the pleural fluid revealed 620 cells, with a differential count of 85% lymphocytes and 15% polymorphs. The sugar and protein levels of the pleural fluid were 50 mg/dL and 3.4 gm/dL, respectively. Serum protein was 6.5 gm/dL. The adenosine deaminase (ADA) level in the pleural fluid was 32 U/L. Pleural fluid cytology was positive for malignant cells. A closed pleural biopsy revealed tumor infiltration by a small round monomorphous cell; however, we were unable to identify a clear lineage in the pathological anatomy. A computed tomography (CT) scan (Fig. 2) revealed a large left pulmonary mass that infiltrated the left pulmonary artery, left main bronchus and main carina as well as a severe pericardial effusion that was primarily localized around the left ventricle. A large subcarinal adenopathy was observed. No abdominal or pelvic abnormalities were found.
A bronchoscopy (Fig. 3) revealed a whitish exophytic lesion that almost completely obstructed the left main bronchus. Bronchial biopsies of the mass and transbronchial needle aspiration (TBNA) of the subcarinal adenopathy were performed. The results suggested a malignant low-grade tumor of possible mesenchymal origin with an uncertain immunohistochemical profile (with tumor cells negative for vimentin, desmin, neuron-specific enolase, epithelial membrane antigen, synaptophysin, S-100, CD117, CD31, CD5 and CD20 and positive only for CD34).
Tumor markers were within normal limits, with the exception of CA-125, which was elevated. On the 7th day after admission, the patient began to experience extremely intense, continuous left shoulder pain that exhibited neuropathic characteristics. Brachial plexus infiltration was suspected; however, due to the patient's intolerance of the supine position, an MRI could not be performed. Due to the absence of a definitive histological diagnosis, the patient was subjected to an open lung biopsy. During this procedure, she exhibited cardiac tamponade and was admitted to the ICU with acute respiratory failure and cardiogenic shock. Unfortunately, the patient died 24 h later.
The family agreed to an autopsy. At the macroscopic level (Fig. 4), the autopsy revealed a tumor mass with large dimensions that weighed 1750 g. The tumor was exclusively intrathoracic, it occupied the entire left hemithorax; surrounded and infiltrated the left main bronchus and left great vessels; was firmly adhered to the chest wall, diaphragm, pericardium, and left atrium wall; and had pushed the heart to the right side. Microscopically (Fig. 5), an intense infiltrate of undifferentiated tumor cells with extensive mitosis was observed. Immunohistochemical assessments indicated that tumor cells were negative for leukocyte common antigen (LCA), cytokeratin, neuron-specific enolase, synaptophysin, smooth muscle actin (SMA), CD1, S-100, CD15, chromogranin, CD57 and CD99 but strongly expressed CK7, 34B12, desmin and vimentin (Fig. 6). This pattern confirmed the diagnosis of DSRCT. Polymerase chain reaction (PCR) analysis to detect the t(11; 22) (p13; q12) translocation produced negative results.