Small cell carcinoma is a disease mainly of pulmonary origin, but in extremely rare cases it can also be observed as a primary mediastinal mass. Here, we present the case of a 48-year-old male patient with a clinical manifestation of superior vena cava syndrome and a CT scan showing a tumor mass in the upper mediastinum compressing the major vessels. A surgical intervention was performed – videomedistinoscopy with partial excision of the tumor from which primary small cell neuroendocrine carcinoma of the mediastinum was detected during histological and immunohistochemical analysis. Multimodal treatment was administered, and after the surgical intervention, the patient was treated with chemotherapy and radiotherapy. The patient was actively monitored, and 8 months after diagnosis, there was a lack of persistent symptoms. From the monitoring PET/CT scan, a minimal single focus with metabolic activity in the mediastinum was observed with significant reduction in tumor size and lack of compression on the mediastinal vessels.

neuroendocrine tumor, mediastinoscopy, small cell carcinoma of the mediastinum

Small cell carcinoma is a disease that mainly affects the lung, but in some cases an extrapulmonary form can also be observed, and the presence of a primary origin in the mediastinum is an extremely rare condition.^[1] Only a small number of cases have been documented in the literature, and due to the aggressive course of the disease, only a few of them have received treatment or have an observed survival rate of more than 12 months.^[2] The origin of the tumor is not clear at this time.^[3] This type of cancer treatment is strictly multidisciplinary and includes surgery, chemotherapy and radiotherapy. The role of surgery is the histological verification of the disease and the aim for cytoreduction of the tumor.^[4] The diagnosis of primary mediastinal small cell neuroendocrine carcinoma (PMSCNC) is based on combined histological and immunohistochemical examination.^[5]

The aim of this study was to present a rare case of mediastinal tumor diagnosed and treated initially with surgical mediastinoscopy followed by adjuvant radiotherapy and chemotherapy.

We present the case of a 48-year-old male patient who was admitted with complaints of chest pain, shortness of breath, and swelling of the face and neck. A computed tomography scan with intravenous contrast of the chest and neck revealed a soft tissue tumor mass measuring 78 × 42 × 39 mm, located in the upper middle mediastinum with compression on the superior vena cava and infiltrating the aortic arch and the brachiocephalic trunk (Figs 1A, 1B).

Figure 1.

A CT image of the mediastinal mass in axial plane. The tumor is marked with red arrows and shows compression on the superior vena cava which has almost closed the lumen. B CT image of the tumor in coronary plane. The tumor formation (red arrow) compresses and almost completely blocks the lumen of the superior vena cava (blue arrow).

Due to the massive infiltration of the large vessels in the mediastinum, it was decided to perform mediastinoscopy with partial excision of the tumor. The intervention was carried out under general intubation anesthesia. A 20 mm cervical access was performed, and a mediastinoscope was inserted in the paratracheal plane to the tumor, where the mass was partially excised (Fig. 2).

Figure 2.

View of the upper pole of the tumor mass during mediastinoscopy.

The procedure was without complications, and the patient was discharged on the second postoperative day. The result from the histological diagnosis was small cell carcinoma, and immunohistochemistry showed positivity for chromogranin A and synaptophysin with negativity for TTF-1 and CDX2.

The patient underwent positron-emission computed tomography (PET/CT), which revealed no other disease foci, so it was assumed to be a primary small cell neuroendocrine carcinoma of the mediastinum. At the same time, the patient’s disease was rapidly progressing, and he had severe superior vena cava syndrome with a new symptom: dysphonia caused by left recurrent laryngeal nerve involvement. A newly appeared right-sided pleural effusion was detected, which was drained followed by radiotherapy (50 Gy) and subsequent 4 courses of chemotherapy with cisplatin and etoposide. The patient was also monitored in the Department of Thoracic Surgery after eight months of treatment, and there were no clinical complaints at the time. His voice was restored, and the swelling in his face and neck had completely subsided. A control PET/CT scan revealed a small area of metabolic activity and a plan for continuing chemotherapy was scheduled.

Mediastinal neuroendocrine carcinomas have been more commonly reported in men, with an average onset age of 54 years.^[6] Primary MSCNC can manifest as any other mediastinal mass. Patients may have symptoms of compression or the tumor may be detected by chance through imaging studies done for other purposes. Malignant mediastinal tumors tend to infiltrate nearby structures and patients may have manifestations of shortness of breath, hoarseness, stridor or superior vena cava syndrome.^[7,8] Superior vena cava syndrome is caused by gradual compression of the vein, resulting in edema and retrograde blood flow. Symptoms may include cough, dyspnea, dysphagia, and swelling or hyperemia of the neck, face, and upper extremities. Often, collateral venous circulation causes dilatation of superficial veins in the chest wall.^[9] Our patient was admitted with superior vena cava syndrome associated with swelling of the face, chest pain, and compression, followed by dysphonia.

The diagnosis of PMSCNC requires both pathological identification by biopsy, revealing the characteristic organoid pattern of the tumor, and immunohistochemical positivity for the typical markers of neuroendocrine tumors. Chromogranin A and synaptophysin are currently considered the most specific immunohistochemical markers for neuroendocrine tumors.^[10] Two major theories have been proposed to explain the genesis of these rare tumors: one involves abnormal cell migration, and the other considers teratomatous origin. According to the first hypothesis, tumors develop from heterogeneous tissue elements that migrated during embryonic development, such as ectopic parathyroid glands and primary intestine remnants.^[11] The second hypothesis proposes that the tumors are caused by a teratoma in the posterior mediastinum. However, there is currently no direct evidence indicating which of these hypotheses is correct. Further research is needed to clarify the histogenesis of primary mediastinal neuroendocrine carcinomas.

Because PMSCNC is a rare disease, there are currently no established clear guidelines for its treatment. Surgical treatment, combined with chemotherapy and radiotherapy, can alleviate patients’ symptoms and extend their survival. Patients with primary neuroendocrine tumors have a poor prognosis due to the high rate of local recurrences and metastases following surgical excision.^[12]

Mediastinoscopy is a minimally invasive way to intervene on upper middle mediastinum structures.^[13] It allows for rapid postoperative recovery of patients due to the lack of transpleural access, which is associated with a higher incidence of complications, the placement of thoracic drains postoperatively, longer pain and physical limitations of the patient. The intervention requires a small incision in the neck and works in an area without pain receptors, resulting in minimal postoperative pain and no need for prolonged analgesia. Because of this, it is the method of choice for treating mediastinal tumor masses that exhibit PMSCNC characteristics.

A large tumor mass located in the anterior-middle mediastinum should raise suspicion for primary small cell neuroendocrine carcinoma of the mediastinum. This tumor can present with superior vena cava syndrome or compression of nearby structures. With timely diagnosis, patients are subject to multimodal therapy and encouraging results are observed, despite the initially poor prognosis and the aggressive course of the disease.

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The authors have declared that no competing interests exist.