A case of middle mediastinal thymoma

Ectopic thymoma in the paratracheal region of the middle mediastinum: a rare case report and literature review

Background

Thymomas generally arise from the thymus in the anterior mediastinum. Ectopic thymomas arising in the middle mediastinum are rare. We present a case of a thymoma arising from the ectopic thymic tissue in the right paratracheal region.

Case presentation

The patient was a 67-year-old male who underwent an enhanced-computed tomography examination as preoperative staging for colon cancer. A 20-mm nodule in the right paratracheal region was found incidentally. Fluorodeoxyglucose (FDG) accumulation was detected in this solitary nodule by FDG-positron emission tomography, mimicking an enlarged, possibly malignant lymph node. The tumor was removed by thoracoscopic surgery, and a postoperative pathological diagnosis of type AB thymoma was made. Foci of ectopic thymic tissues were found adjacent to the thymoma. The patient was disease-free and without recurrence 2 years postoperatively.

Conclusions

Including the present case, 13 cases of ectopic paratracheal thymoma have been reported in the English literature, all of which were found on the right side of the paratracheal region. Although ectopic thymomas in the paratracheal region are rare, thymomas may be considered as a differential diagnosis for a paratracheal nodule.

Thymoma in middle mediastinum that induced tracheal compression-Case report and literature review

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A thymoma mainly occurs in the anterior mediastinum, while few are seen in the middle mediastinum.

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This is the first case of a mediastinum thymoma induced severe tracheal compression in literature.

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In our review of middle mediastinum thymoma cases, none were Masaoka stage III or IV, while the majority (9/13, 69.2%) were WHO type A or AB.

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A thymoma should always be considered in differential diagnosis of neoplasm, even when occurring in the middle mediastinum.

Background

A thymoma, an epithelial neoplasm of the thymus, mainly occurs in the anterior mediastinum, while few are seen in the middle mediastinum.

Case presentation

An 83-year-old male was referred for an incidental mass in the middle mediastinum. He had severe dementia and denied symptoms. Our follow-up computed tomography (CT) examinations had revealed the progress of tracheal compression along with tumor enlargement for 2 years. At 85 years old, we performed a thymomectomy via a median sternotomy to avoid complete trachea obstruction. The pathological diagnosis was WHO type A thymoma, Masaoka stage II. One year after surgery, the patient was free of disease.

Discussion

Thymomas occurring in the middle mediastinum are rare. In our review of 13 such cases, none were Masaoka stage III or IV, while the majority (9/13, 69.2%) were WHO type A or AB.

Conclusion

We encountered a thymoma in the middle mediastinum that showed enlargement over a 2-year period, inducing severe tracheal compression. Thymomas can occur widely in pharyngeal pouch-derived locations and should be considered in differential diagnosis of a middle mediastinum tumor.

Massive thymoma of the mid-posterior mediastinum: an unprecedented case in a young adult

We report an unprecedented case of ectopic thymoma in a young adult. A 33-year-old male presented with a 10-day history of non-productive cough and fever. Investigation revealed mediastinal widening without pulmonary involvement. Computed tomography showed a large mass-14.8 × 10.8 × 8.4 cm-in the mid-posterior mediastinum, and a biopsy obtained by video-assisted thoracoscopy indicated that the mass was a tumor. Immunohistochemistry showed combined thymoma type AB1. Because of the considerable proportions of the tumor and its close proximity to major structures, the patient was treated with chemotherapy.