A Rare Case of Multilocular Thymic Cyst with Follicular Lymphoid Hyperplasia: Radiologic and Histopathologic Features

Multilocular Thymic Cyst with High F18 Fluorodeoxyglucose Uptake and Rheumatoid Arthritis: A Case Report

Background: multilocular thymic cysts are uncommon acquired cysts in the anterior mediastinum caused by incomplete thymic involution. They may be associated with autoimmune diseases, such as rheumatoid arthritis and systemic sclerosis. Methods: a 61-year-old man with a history of rheumatoid arthritis for 8 years was referred to our unit because of a multiloculated mass in the anterior mediastinum with a high F18 fluorodeoxyglucose uptake at PET-CT scan. Histology showed a multilocular thymic cyst with lymphoid tissue, organized in germinal centers and internodal areas. Results: rheumatoid arthritis-related symptoms progressively disappeared after the excision of the mass. Conclusions: to our knowledge, this is the first report in the English language of rheumatoid arthritis symptoms improvement after multilocular thymic cyst surgical removal.

Lymphoid follicular hyperplasia arising from the chest wall presenting as a substantial mass

Lymphoid follicular hyperplasia (LFH) is a benign lymphoproliferative disease. Although it can occur within the thoracic cavity, LFH originating from the chest wall has not been reported. A 79-year-old woman was incidentally found to have a well-defined mass on the left posterior chest wall during a preoperative examination for aortic valve replacement. The mass had slowly grown over 6 years. Thoracoscopic surgical resection was performed without complications. Pathological examination ruled out lymphoproliferative diseases, such as Castleman disease or malignant lymphoma, and a diagnosis of LFH was made. Although LFH generally has a good prognosis, surgical resection is recommended for diagnostic and therapeutic purposes owing to the possibility of malignancy masquerading as a reactive lesion. This is the first report of an LFH arising from the chest wall with imaging findings similar to other benign tumours. Its potential as a differential diagnosis for tumours with similar imaging findings is highlighted.

Multilocular thymic cysts can be easily misdiagnosed as malignant tumor on computer tomography: A case report

BACKGROUND

Multilocular thymic cyst (MTC) is a rare mediastinal lesion which is considered to occur in the process of acquired inflammation. It is usually characterized by well-defined cystic density and is filled with transparent liquid.

CASE SUMMARY

We report on a 39-year-old male with a cystic-solid mass in the anterior mediastinum. Computer tomography (CT) imaging showed that the mass was irregular with unclear boundaries. After injection of contrast agent, there was a slight enhancement of stripes and nodules. According to CT findings, it was diagnosed as thymic cancer.

CONCLUSION

After surgery, MTC accompanied by bleeding and infection was confirmed by pathological examination. The main lesson of this case was that malignant thymic tumor and MTC of the anterior mediastinum sometimes exhibit similar CT findings. Caution is necessary in clinical work to avoid misdiagnosis.

Clinical characteristics and management of primary mediastinal cysts: A single-center experience

Background

In this study we aimed to assess the clinical outcomes of performing video‐assisted thoracic surgery (VATS) to treat primary mediastinal cysts (PMCs) and investigate the clinical factors which increase the difficulties associated with VATS.

Methods

The medical records of all consecutive PMC patients, who underwent surgical resection from April 2001 to July 2016, were reviewed and 282 patients were included. Clinical characteristics, imaging features, and surgical outcomes were analyzed. Follow‐up data were successfully obtained from 230 PMC patients by telephone or outpatient clinic annually. The latest follow‐up was July 2019.

Results

VATS was performed in 278 patients and four patients were converted into thoracotomy. The mean operation time and intraoperative bleeding were 102.4 ± 40.9 minutes (range 25–360 minutes) and 52.4 ± 75.1 mL (range 5–600 mL), respectively. The intra‐ and postoperative complication rates were 2.8 and 5.7%, respectively. Seven patients with bronchogenic cysts showed severe cyst adhesion to vital mediastinal structures and thus had incomplete resection. Multivariable logistic analysis revealed that a maximal cyst diameter greater than 5 cm was significantly associated with increased risks of operation time extension (OR = 2.106; 95% CI: 1.147–3.865, P = 0.016) and intraoperative blood loss increase (OR = 4.428; 95% CI: 1.243–16.489, P = 0.022). A total of 230 patients had follow‐up data. The median follow‐up time was 70 months (range, 36–210 months). No local recurrence was observed.

Conclusions

Surgical resection by VATS may be recommended for PMC management as a primary therapeutic strategy. Cysts with a maximum diameter greater than 5 cm or cysts adjacent to vital mediastinal structures can increase the surgical difficulties.

Key points

• Significant findings of the study

A diameter >5 cm and adhesions significantly increased the risk of operation time extension together with increased blood loss.

• What this study adds

Cysts with a diameter >5 cm or those adjacent to vital mediastinal structures increased the potential for surgical difficulties.