The institutional review board of The Third People’s Hospital of Zhengzhou approved this work. The patient provided informed consent for publication of the case. A 41-year-old woman presented with a sore throat for 3 days and hoarse voice for 1 day. One day before admission, a chest CT scan (Fig. 1A) showed a large fusiform high-density shadow in the posterior tracheal space (maximum cross-section of 34 x 25 mm, CT value 50 HU). The adjacent tracheal wall was compressed, the lumen was slightly flattened, and the boundary of the adjacent esophageal wall was partially unclear. Three days after admission, the patient gradually developed hoarseness, dry cough, wheezing, difficulty swallowing, and progressive swelling and tenderness on the right side of the face and neck. Chest 64-row enhanced CT (Fig. 1B) showed a soft tissue mass on the right side of the posterior superior mediastinum (uneven density, mild enhancement, CT value range of -5 HU–130 HU, and maximum cross-sectional area of 56x36x32 mm), the pressure of the adjacent trachea was significantly higher than before, and the local wall of the middle and upper esophagus was thickened. Ultrasonography (US) of the neck (Fig. 1C) indicated a solid mass on the right side of the upper mediastinum near the upper sternal fossa (hypoechoic mass, maximum cross-sectional area of 52x28x25 mm, clear border, irregular shape, deep part extending to the mediastinum, partly due to the obscurity of the sternum). The large blood vessels in the neck were immediately behind the upper edge, and the blood flow signal in the neck was unsatisfactory. The diagnosis was considered at this time, including bleeding from the right upper mediastinal mass, mediastinal metastasis of esophageal cancer and bleeding in metastatic foci, neurogenic tumor, or paratracheal cyst. Considering the rapid progression of the patient's condition, to alleviate the symptoms of local compression, the treatment plan was given, including (1) an emergency puncture to confirm the pathological diagnosis; (2) radiotherapy immediately after the puncture; and (3) methylprednisolone 40 mg/day×3 days. Fiberoptic bronchoscopy was performed before the puncture, and the results (Fig. 1D) indicated a normal glottis and external pressure stenosis in the right posterior wall of the trachea. The upper end was approximately 1 cm from the glottis, and the lower end was approximately 2 cm from the carina. The upper section was narrowed by approximately 70%, and the middle and lower sections were narrowed by approximately 40%. The right posterior wall was slightly infiltrating, and mucosal congestion and edema were obvious. Based on the degree of airway compression seen in the patient under tracheoscopy, tracheal intubation was temporarily not performed. When the mediastinal mass was punctured under CT guidance, the tension in the mass was high, and 15 ml of dark red bloody non-coagulated liquid was withdrawn and submitted for pathological examination.
After the puncture, the patient felt chest tightness, hoarseness, and swelling of the right side of the face, so no radiotherapy was given. The post-pathological results revealed fibrous adipose tissue and a few glandular epithelial exfoliated cells, with no tumor cells detected. After further improvement of the relevant examinations, granulomatous disease, tuberculosis infection, thyroid disease, and cancer were excluded. At this time, the patient had been hospitalized for 13 days, and the cause of the mediastinal mass was still not detected. Reexamination of chest CT (Fig. 2A) showed that the soft tissue mass on the right side of the posterior superior mediastinum was smaller than that on the front. The pressure on the adjacent tracheal wall was significantly reduced. The thickening of the local wall of the middle and upper esophagus was slightly less than before. Reexamination of neck US (Fig. 2C) showed a cystic echogenic mass approximately 59x26 mm deep on the right side of the superior sternal fossa, with poor internal translucency, no blood flow signal in it, and no local blood vessels. The margin was immediately adjacent to the inferior pole of the thyroid, and the lower margin was located at the upper edge of the aortic arch. Compared with the previous US, local compression was significantly alleviated. The lesion had a fluid echo, and a band-like separation echo was seen. In the thyroid consultation, the possibility of the patient having parathyroid cysts or parathyroid adenoma was considered. To further alleviate local compression and clarify the pathological diagnosis, under the guidance of ultrasound, a mass puncture was performed, and 20 ml of dark red non-coagulating liquid was withdrawn. Then, US was immediately reexamined and showed that the mass shrunk significantly (Fig. 2D). Reexamination of chest CT (Fig. 2B) showed that the tracheal compression was almost completely relieved, and the mediastinal mass was significantly reduced. On the 14th day after admission, the pathological report of the second mediastinal puncture showed that the liquid sediment in the mediastinal cyst had a small number of glandular epithelial cell clusters, foam cells, lymphocytes and neutrophils in the background of the red blood cells prompted from cystic lesions of the parathyroid gland. Simultaneously, parathyroid hormone was 210 pg/ml (normal reference range: 11–81 pg/ml). The results of 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) examination of the parathyroid glands showed that there were abnormally increased areas of punctate radioactive distribution below the lower pole of the right lobe of the thyroid and the upper pole and lower pole of the left lobe, and the parathyroid imaging was suspiciously positive (possibly hyperparathyroidism). Then, the patient was transferred to the Surgery Department for surgical treatment. Postoperative pathology confirmed parathyroid adenoma with cystic changes in some areas (Fig. 2E and F). After 3 months of follow-up, the patient showed no abnormalities.