Cystic lesions of the mediastinum

Clinical features, diagnosis and thoracoscopic surgical treatment of thymic cysts

Background

Thymic cysts are rare benign developmental anomalies and there is no consensus management for thymic cysts. The aim of this study was to disclose the efficacy of perioperative diagnosis for thymic cysts by chest computerized tomography (CT) and to elucidate the surgical procedure by video-assisted thoracic surgery (VATS) in the management of thymic cysts.

Methods

We retrospectively reviewed 108 consecutive thymic cyst patients who underwent VATS at our institution between April 2001 and August 2015. All patients received chest CT preoperatively and underwent VATS treatment. Clinical characteristics, imaging features and surgical exploration were taken into consideration to determine the surgical extent.

Results

Multivariate logistic regression analysis showed that a diameter ≤3 cm [risk ratio (RR) =4.525; 95% confidence interval (CI), 1.027-20.000; P=0.046] and an unenhanced CT value >20 Hounsfield unit (Hu) (RR =7.043; 95% CI, 1.750-28.345; P=0.006) were independent factors of incorrect diagnosis of chest CT. Three different surgical procedures were performed, which included thymectomy (n=49), cyst resection and partial thymectomy (n=46), and extended thymectomy (n=13). No serious postoperative complications were observed. The median follow-up-time was 60.6 months (range, 12.0-168.0 months) with no late complications or recurrences.

Conclusions

A diameter ≤3 cm and an unenhanced CT value >20 Hu were independent factors of incorrect diagnosis of chest CT. VATS is a reliable approach for the surgical resection of thymic cysts. We think that local resection is adequate for simple thymic cysts. However, thymectomy is necessary when there is suspicion of a thymoma or multilocular thymic cyst, and radical thymectomy is advisable for patients with autoimmune diseases.

Mediastinal pathology and the contributions of Dr. Juan Rosai

Dr. Juan Rosai is one of the most prolific contributors to the literature on mediastinal pathology, and he has added steadily to that body of work over a 50-year period. Rosai has written several landmark articles in this topical area, including articles on thymic epithelial lesions, mediastinal neuroendocrine tumors, mediastinal lymphoma and other hematopoietic lesions, thymolipoma, thymoliposarcoma, mediastinal solitary fibrous tumor, intrathymic langerhans-cell histiocytosis, mediastinal germ cell neoplasms, and multilocular thymic cyst. This review recounts his role as one of the principal figures in the surgical pathology of mediastinal diseases.

Massive pericardial effusion and multiple pericardial masses due to an anterior mediastinal teratoma rupturing in pericardial sac

A 25 -year-old Egyptian man presented to our unit for the evaluation of a large pericardial effusion. At 1 month before presentation he suffered from daily bouts of fever. Chest x-ray revealed cardiomegaly, echocardiography showed large pericardial effusion and multiple pericardial masses. Needle pericardiocentesis revealed a bloody exudate with no malignant cells. Chest CT showed a well-circumscribed anterior mediastinal cystic mass with a central fat component and foci of calcification. MRI of the chest similarly showed no intracardiac extension. A cystic mass 7×9 cm was removed via a median sternotomy with uneventful postoperative course. Pathological evaluation revealed a benign cystic teratoma and a thymic cyst. Most cystic teratomas are accidentally discovered, large ones can cause symptoms through the compression of mediastinal structures or rupture in pericardial sac.

Spontaneous infection of a stable mediastinal cystic mass: A case report

Mediastinal cysts have an unpredictable course but can cause complications such as infection or local pressure effects. Persons with mediastinal cysts can be asymptomatic for many years or can develop symptoms as a result of complications of the cyst. There is a lack of consensus on the best approach to managing those patients without symptoms. In this case report, a 56 year old woman with an indolent mediastinal cyst initially managed conservatively suddenly developed symptoms suggestive of an infected mediastinal cyst requiring surgical resection.

Cystic well-differentiated neuroendocrine carcinoma (carcinoid tumor): a clinicopathologic and immunohistochemical study of two cases

Two cases of primary neuroendocrine carcinoma (carcinoid tumor) arising in the walls of a multilocular thymic cyst (MTC) are described. The patients were 2 men, ages 36 and 44 years. Clinically, the patients had chest pain, cough, and dyspnea. Radiographic evaluation demonstrated the presence of anterior mediastinal tumor in both patients, and complete surgical resection of the tumor mass was performed. The tumors measured approximately 6 and 8 cm in greatest dimension and were cystic with solid areas but did not show areas of necrosis or hemorrhage. Histologic examination revealed a cystic tumor with features similar to those previously described for MTCs. In addition, in the walls of the cystic structures, there was cellular proliferation arranged in a nesting growth pattern, similar to the more solid areas of the tumor. The tumor was characterized by a homogenous cellular proliferation with mild cellular atypia and no more than 2 mitotic figures per 10 high-power fields. Immunohistochemically, the tumor cells showed strong positive reactions for keratin and neuroendocrine markers, ie, chromogranin and synaptophysin. Both patients were alive after periods of 12 and 18 months.