Benign cystic mediastinal teratoma presenting as a massive pleural effusion in a 17-year-old boy

Mediastinal Germ Cell Tumors: A Review and Update on Pathologic, Clinical, and Molecular Features

Mediastinal germ cell tumors (MGCTs) are the most common extragonadal germ cell tumors (GCTs) and most often arise in the anterior mediastinum with a male predilection. MGCTs also have a predilection for patients with Klinefelter syndrome and possibly other genetic conditions. MGCTs, as GCTs at other extragonadal sites, are thought to arise from germ cells improperly retained during migration along the midline during embryogenesis. Similar to their counterparts in the testes, MGCTs are classified into seminomatous and nonseminomatous GCTs. Seminomatous MGCT represents pure seminoma, whereas nonseminomatous MGCTs encompass pure yolk sac tumors, embryonal carcinoma, choriocarcinoma, mature or immature teratoma, and mixed GCTs with any combination of GCT types, including seminoma. Somatic-type or hematologic malignancies can also occur in association with a primary MGCT. MGCTs share molecular findings with GCTs at other sites, most commonly the presence of chromosome 12p gains and isochromosome i(12p). Treatment includes neoadjuvant chemotherapy followed by surgical resection of residual tumor, with the exception of benign teratomas, which require only surgical resection without chemotherapy. In this review, we highlight and provide an update on pathologic, clinical, and molecular features of MGCTs. Immunohistochemical profiles of each tumor type, as well as differential diagnostic considerations, are discussed.

Mediastinal cystic teratoma misdiagnosed as pleural tuberculosis: A case report and review of 53 cases revealed by pleural effusion

Mediastinal teratoma (MT) can be misdiagnosed for a long period and revealed by fatal pleural effusion at any age. In high burden tuberculosis settings, it is important to consider MT for extra-pulmonary tuberculosis not responding to medical treatment.

Mediastinal teratoma presenting with hemoptysis and pleuritis misdiagnosed as tuberculosis (empyema)

Background

Mediastinal teratoma is uncommon in children. It can be very difficult to diagnose especially in early stage. Rarely, teratoma may rupture into adjacent structures and lead to lung lesions or pleuritis. The main rarity of our reported cases was the dynamic imaging findings very similar to the developmental process of tuberculosis in patients 1 and 2, the pachypleuritis in patients 2 and 3, the extremely elevated inflammatory markers very similar to empyema in patient 3, and the extremely atypical tumor shape in all patients.

Case presentation

We present three pediatric patients presenting predominantly with recurrent hemoptysis and/or chest pain who were ultimately diagnosed with mediastinal teratoma containing pancreatic tissue. All three patients were initially suspected to have tuberculosis or empyema, and underwent relevant treatment, but without improvement. Patient 1 had left hilar enlargement, and subsequently an enlarging calcified cavity within high-density consolidation was identified. Patient 2 initially presented with right-sided pulmonary consolidation and pleuritis, and subsequently developed right lower lobe calcification, pleural thickening, and irregular soft tissue in the right inferior mediastinum. Patient 3 was initially found to have right lobe consolidation accompanied by a massive right-sided pleural effusion with extremely elevated inflammatory markers in serum and pleural effusion. The effusion later acquired heterogeneous density and appeared to become encapsulated. In patients 2 and 3, pleural biopsy identified fibrous tissue (with and without granuloma). Thoracotomy/thoracoscopy revealed mediastinal teratoma in each case, all of which were completely excised and the patients made uneventful recoveries. Histopathologic analysis revealed mature cystic-solid teratoma containing pancreatic tissue in all patients, and calcification in patients 1 and 2.

Conclusions

Clinicians should be mindful that mediastinal teratoma is a potential cause of hemoptysis, lung lesions and pleuritis. Calcification and pachypleuritis on chest imaging especially in patients without fever should be highly suspected of mediastinal teratoma. Pleural biopsy sometimes fails to assist in making a definitive diagnosis.

Pleural effusion as a rare manifestation of mediastinal teratoma: A case report

Pleural effusion as one of the most common manifestations of pulmonary diseases is a rare symptom of anterior mediastinal teratoma that might mislead general physicians. In this study we report a rare case of pleural effusion and anterior mediastinal teratoma accompanying each other. The patient was a 21-year-old woman who suffered from dyspnea, cough, fever and manifestations of pleural effusion were obvious in chest X Ray (CXR). Computed tomography scan showed a cystic mass with lipid component. After thoracotomy, a mass was taken out from medial lobe of right lung and the results of pathology showed the mature mediastinal teratoma. The patient remained well with no evidence of recurrence on follow-up CXRs 6 months after the surgery.