In February 2021, a 53-year-old man who had a smoking and drinking history of more than twenty years was admitted to our hospital with complaints that his front chest pain had lasted for half a year without breathlessness, wheeze, or stridor. There were no abnormalities of the chest shape, and any scars or skin deposits on the chest wall. The breath sound vesicular and no additional sounds, namely, crackles and pleural friction rub occurred. In no time, chest CT detected three soft tissue masses with irregular margins and mild heterogeneous enhancement in his mediastinum, the biggest one was of 59 x 39 x 26 mm3 in the anterior mediastinum and infiltrated the sternum, and the other lesions less than 22 mm located in the upper and lower mediastinum was close to the aorta ( Figure 1A ). However, most of his laboratory tests were normal, namely, blood cell counts, blood coagulation tests with tests of prothrombin time, and liver function tests. Regarding to tumor markers, serum level of AFP was normal (0.89 ug/L, normal range, 0-20.0 ug/L) and carcinoembryonic antigen (CEA) was slightly increased (5.08 ug/L, normal range, 0-5.0 ug/L), CA125 and CA199 were also normal. No abnormality was found in the hepatitis tests, namely, hepatitis B and hepatitis C. Initially, we diagnosed a likelihood of lung cancer, invasive thymoma or lymphoma.
In order to confirm the diagnosis, a percutaneous needle biopsy of the anterior mediastinal lesion was performed under CT guidance. The histopathologic examination revealed that the rows and small nests of neoplastic cells were very pleomorphic. ( Figure 1B ). By immunohistochemistry, the tumor cells stained positive for different cytokeratin antibodies (CK19, CK7, and CK20). HepPar1, focal AFP, and CD117 were also positive. Germ cell markers (CD30, OCT 3/4) along with other markers were negative, namely, CK5/6, TTF-1, NapsinA, TdT, Vimentin, P40, CD20, CD79a, CD3, CD5, Arginase-1, SALL4, P63, Syn, SATB2, CDX-2. Proliferative activity by Ki67 labeling index was high (70%). The pathologist drew a conclusion that it was consistent with the epithelial malignant tumor. Considering the hepatoid differentiation phenotype, it was necessary to distinguish the hepatoid adenocarcinoma from hepatocellular carcinoma metastasis. However, mediastinal metastases from a gastric hepatoid carcinoma or hepatocellular carcinoma were ruled out in this case soon, because no obvious gastric or liver tumors were apparent on the preoperative CT contrast-enhanced scan. HCCs are often associated with similar clinical context like cirrhosis, chronic hepatitis B or chronic hepatitis C infection. HAC of lungs have been reported with positive TTF-1 which was negative in the present case. An angiography also illustrated tumors stained and the left internal thoracic artery was expanding and supplying blood of the tumors ( Figure 1C ). The bronchial artery, the most common blood supply artery of pulmonary cancer, was normal. Taking these results together, the patient was diagnosed with HAC of mediastinum. Because of the invasion of the sternum and the close relationship to the aorta of multiple lesions, the patient was not suitable for surgical resection, and debulking was refused from the patient and his family for the risks. The lesions are relatively localized and obviously stained by the left internal thoracic artery. Therefore, a transcatheter chemoembolization of feeding artery of the tumor was performed with lipiodol-epirubicin farrago after the left internal thoracic artery had been prophylactic embolization using steel coils. Local-regional chemotherapy was applied to increase the drug concentration and reduce systemic toxicity. Transarterial infusion of palliative chemotherapy was administered with FOLFOX (oxaliplatin 85 mg/m2 on day 1; LV 200 mg/m2 on days 1 and 2; and FU 400 mg/m2 followed by 600 mg/m2 on days 1 and 2). A following FDG-PET/CT scan on 15 March 2021 revealed an enlargement of the biggest mass, which had abnormal uptake of FDG (SUVmax = 15.3). Meanwhile, PET/CT showed no lesion in the liver and stomach, except for the known mediastinal lesions. Moreover, there was an elevation of ferroprotein about 1,325.38 ug/L (normal range is 16.40-323.00 ug/L). The patient was treated with 200 mg of Sintilimab, the PD-1 inhibitor usually used in lymphoma and advanced non-small cell lung cancer.
The patient received additional four cycles of regional chemotherapy with FOLFOX4 regimen by the left internal thoracic artery infusion combined with systemic anti-PD-1 therapy every three weeks. The latest CT scan on 28 July 2021 showed that the size of the biggest lesion was minimized to 29 x 26 x 19 mm3 and the other lesions disappeared ( Figure 1D ). Ferroprotein has fallen to 430.91 ug/L. No significant adverse event was found, and the patient still remains alive and continues to follow up till 12 November 2021.