A Surgical Case of Heterotopic Thymic Carcinoma Coexisting With Hepatocellular Carcinoma

Abstract

Although thymomas arising in ectopic regions other than the upper anterior mediastinum are well known, thymic carcinomas in ectopic locations are very rare. On the other hand, the therapeutic strategies for synchronous double primary cancers arising from different organs are still controversial. We have experienced a case of thymic carcinoma in an ectopic location with a coexisting hepatocellular carcinoma (HCC) for which management presented a number of difficulties. A 67-year-old man with HCC presented with a slow-growing nodular shadow in the left lower anterior mediastinum, i.e. the left cardiophrenic angle. During 7 years of intensive treatment for the HCC, the mediastinal nodule, which had been suspected clinically to be a lymph node metastasis from the HCC, grew to 4 cm in diameter. Surgical intervention for the mediastinal nodule was carried out for treatment and definitive diagnosis using a mediastinoscope inserted via a transverse xyphoid incision. Intraoperative pathological diagnosis from frozen sections of the mediastinal nodule revealed thymic carcinoma, and therefore the procedure was converted to thymothymectomy via a median sternotomy. Despite postoperative multimodality treatment, the patient died due to multifocal metastasis and pleuritis carcinomatosa from the thymic carcinoma within 7 months after the thymothymectomy. The unusual location of the thymic carcinoma in this case and the synchronous nature of the coexisting primary HCC resulted in delay of surgical resection for the former. More intensive observation and early intervention in the form of diagnostic or therapeutic resection should be performed for any mediastinal nodule that appears during the course of treatment for HCC. J Med Cases. 2015;6(9):433-436 doi: http://dx.doi.org/10.14740/jmc2267w