Mucosa-associated lymphoid tissue lymphoma in the thymus of a patient with systemic lupus erythematosus

Mucosa-associated lymphoid tissue (MALT) lymphoma arising from the thymus is extremely rare. We present a case of a 23-year-old woman with systemic lupus erythematosus (SLE) who was diagnosed with thymic MALT lymphoma. In 2004, she was diagnosed with a mediastinal tumor on chest radiography during medical follow up for SLE. An anterior mediastinal tumor with multilobular cysts was identified by computerized tomography and magnetic resonance imaging. A thymic malignancy was suspected and an extended thymectomy was performed. After histological and immunohistochemical examinations, the thymic tumor was diagnosed as a MALT lymphoma. There was no recurrence in the 2-year follow-up during which time there was no further treatment.     

Thymic mucosa-associated lymphoid tissue lymphoma involving lymph nodes

INTRODUCTIONThymic mucosa-associated lymphoid tissue (MALT) lymphoma involving lymph nodes is quite rare with only 13 previous cases reported in the literature.PRESENTATION OF CASEThe 33-years-old female was referred to our department for the investigation of abnormalities on computed tomographic (CT) scans. CT scans showed a 9-cm × 3-cm mass composed of a mixture of soft tissue and fat at the anterior mediastinum with lymphadenopathy in the neck, axillary and mediastinal regions. She was underwent complete surgical resection of the mass with regional lymph node dissection through a median sternotomy. Histological examination of the surgical specimens confirmed the diagnosis of MALT lymphoma arising in the thymus with nodal metastasis. She achieved complete remission after postoperative rituximab combined chemotherapy.DISCUSSIONThymic MALT lymphoma occurs most frequently in Asian female aged 40–60 years and commonly appears anterior mediastinal masses on CT scans. The excised tissue is necessary to confirm the accurate histological diagnosis. The disease usually remains localized for a long time, making local surgical resection highly effective. However, when the lymph nodes are involved, effective treatment approaches of the disease is still undefined.CONCLUSIONWe report a case of thymic MALT lymphoma involving lymph nodes, in which the patient was successfully treated with primary site resection with regional lymph node dissection followed by rituximab combined chemotherapy. Surgery provided not only a useful approach for collecting tissue for an accurate histological diagnosis, but also an effective local treatment, even in the case of advanced-stage thymic MALT lymphoma.     

Distribution of thymic tissue in the mediastinal adipose tissue removed at the thymectomy in 47 patients with myasthenia gravis]

In this report, the distribution of thymic tissue in the mediastinal adipose tissue was examined histologically in 54 patients with myasthenia gravis underwent extended thymectomy. In fourty-seven of 54 patients, the mediastinal adipose tissues were removed from 6 different parts adjacent to the thymus, i.e., right upper, right middle, right lower, left upper, left middle, and left lower, respectively. Upper area means of around the upper pole of thymus, middle area means of around hilum and lower area means of around from lower pole of thymus to diaphragma. In the mediastinal adipose tissue, thymic tissue was found outside the thymus lobes in 41 (75.9%) of 54 patients. The each prevalence (percent of occurrence) of 6 areas were as follows: 15.0% in the right upper area, 21.4% in the right middle area, 19.0% in the right lower area, 17.5% in the left upper area, 66.7% in the left middle area and 33.3% in the left lower area. There was significant differences in the prevalence of the left middle area according to the other 5 areas (p < 0.01). There were no significant differences in the prevalences among sex, Osserman type, duration of the disease, pre-operative treatment and histological findings or removal thymus. There were significant differences in the prevalence of all according to the proportion of thymic tissue in the thymus (0.01 < P < 0.05). In conclusion, it is suggested that for the removal of all thymic tissue, the sufficient procedure required utmost care especially to the left middle area around thymus.(ABSTRACT TRUNCATED AT 250 WORDS)     

Technik der Thymuschirurgie

The group of thymic tumors includes thymomas, thymic carcinomas and neuroendocrine thymic tumors (NETT). They are rare tumor entities but represent the majority of malignant tumors of the anterior mediastinum in adult patients. The biological behavior is characterized by slow tissue infiltration and locoregional tumor spread. Complete surgical resection is the foundation of the treatment of thymic tumors. Early tumor stages can be addressed by minimally invasive surgical procedures. In 30?% of patients the tumors already infiltrate additional mediastinal structures, the lungs or the chest wall warranting extended surgical approaches. This review article summarizes the operative approaches available for thoracic surgeons. Knowledge of the available surgical techniques in thymic surgery can be transferred to other mediastinal tumors.     

Role of flourine-18 fluorodeoxyglucose positron emission tomography in thymic pathology.

OBJECTIVE: To evaluate the utilization of positron emission tomography (PET) scan with fluorine-18 fluorodeoxyglucose (FDG) in thymic pathology. METHODS: Twenty-five consecutive patients with thymic pathology underwent FDG-PET after being evaluated by computed tomography (CT). The indication for CT was myasthenia gravis in 10, anterior mediastinal mass in 7, and recurrent thymic tumor after surgical excision in 8 patients. The results of PET were compared with results obtained by CT, and histopathologic examination of the surgical specimens. RESULTS: All mediastinal abnormal thymic tissue showed FDG uptakes. FDG-PET managed to differentiate between thymic hyperplasia and thymoma in myasthenia gravis group (n=10) in which CT images were questionable in two patients. There was one case of ectopic thymic tissue which was not diagnosed preoperatively. There were no false-negative results for both CT and FDG-PET in seven patients with thymoma presented as anterior mediastinal mass. However, PET scan predicted thymic carcinoma in one patient. PET was superior to CT scan in localization of recurrent thymoma in two patients, and equal to CT in detecting metastatic lesions in six patients during the follow-up after thymoma excision. CONCLUSIONS: In myasthenia gravis, selective use of FDG-PET is useful in differentiating thymoma from hyperplasia, especially when CT scan is controversial, but fails to recognize ectopic thymic tissue. FDG-PET may differentiate thymoma from thymic carcinoma. FDG-PET is also useful in follow-up patients, who underwent thymoma excision, when there is suspicion of recurrence or metastasis.     

Surgical approach for histopathological determination of anterior mediastinal malignant lymphoma

In a retrospective review of all patients who admitted our hospital between January 1992 and December 2006, we identified 9 with anterior mediastinal malignant lymphoma. They represented 6.8% of the 133 patients with mediastinal tumor. Histology revealed 3 cases of primary mediastinal large B-cell lymphoma, 2 of Hodgkin lymphoma, 2 of precursor T-lymphoblastic lymphoma and 2 of thymic extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) lymphoma. Careful attention should be paid to the relatively high incidence of malignant lymphoma in the anterior mediastinal tumors. It is highly important to differentiate of malignant lymphoma from other diseases that shape anterior mediastinal tumor to avoid unnecessary operation. Early and accurate diagnosis of these tumors is also important because some of these patients require immediate treatment by hematology specialists.     

Distribution of thymic tissue at the anterior mediastinum. Current procedures in thymectomy.

The distribution of thymic tissue at the anterior mediastinum was examined histologically in 18 cases following the removal of the adipose tissue which was located outside the thymic capsule at the time of thymectomy for myasthenia gravis. The gross adipose tissue revealed the presence of histological thymic tissue, including Hassall's bodies, in 13 of 18 cases. In order to be sure of extirpating all of the thymic tissue, the adipose tissue at the anterior mediastinum as well as the gross thymus should be removed.     

Giant Thymolipoma: Case Report of an Unusual Mediastinal Tumor

Thymolipoma is an uncommon benign neoplasm of the thymus composed of mature adipose and thymic tissue. The diagnosis of thymolipoma should be considered in the case of a mediastinal mass with fat density, especially if it is interspersed with strands of soft tissue attenuation on computed tomography scans. However, it is sometimes difficult to differentiate radiologically between a thymolipoma and other mediastinal fatty tumors.Here we present a patient with a huge mediastinal mass that proved to be a thymolipoma.     

Cavernous hemangioma with hematoma in the chest wall due to penetration from the anterior mediastinum

The patient was a 51-year-old man who visited the hospital with swelling of the anterior chest. Chest computed tomography detected a tumor developing from the anterior mediastinum to the anterior chest wall. There was weak contrast enhancement inside the tumor, and calcification was observed in the central region. A soft tumor with an obscure border and that adhered to the back of the left sternum was surgically removed with thymic fat including the region of the chest wall that had been penetrated by the tumor. The tumor measured 30 × 25 mm, and a phlebolith was observed in the center. The pathological tissue was diagnosed to be a cavernous hemangioma, and there were no malignant findings in the endothelial cells. Mediastinal hemangioma should therefore be kept in mind during an evaluation of mediastinal tumors, and one must also take into account the effect on the surrounding organs. An erratum to this article is available at .     

Combined unilateral-thoracoscopic and mediastinoscopic thymectomy

To achieve maximal benefit, after thymic tissue and mediastinal fat were removed by thoracoscopic thymectomy, a transverse cervical incision allowed access to remove fat in the neck. A mediastinoscopy was then performed for removal of the fat in the retrosternal area superior to the innominate vein. In 15 cases, ectopic thymic tissue was found. There were three cases in which the residual superior horns of thymus were found in the neck and three in the retrosternal area. The combined use of a mediastinoscope and a thoracoscope can remove almost all the thymus, including ectopic tissues. Long-term results are still being awaited.     

Mediastinal cyst with rim calcification

A 58-year-old man who had been undergoing treatment for chronic pericarditis for 15 months was found to have a calcified mediastinal mass shadow on a chest X-ray and was referred to us for further study and treatment. Chest computed tomography and magnetic resonance imaging showed an anterior mediastinal multilocular tumor with rim calcification. Tumor markers were within normal limits. The patient was preoperatively diagnosed as having a calcified mediastinal cyst, and median sternotomy was performed to remove the cystic tumor and the surrounding thymic tissues. Histological examination revealed that the cyst wall consisted of dense fibrous tissue and calcification without epithelial cell lining on the inner surface. Thymic tissue was present around the cyst wall. Although we suspected a thymic cyst from the intraoperative findings, the final diagnosis was made as mediastinal cyst with rim calcification. We herein present a rare case of mediastinal cyst with rim calcification.     

Thymolipoma associated with myasthenia gravis

A 51-year-old woman with a 3-year history of diplopia was admitted to our hospital. Repetitive stimulation of the right median nerve revealed decreasing hand muscle responses. Edrophonium chloride administration alleviated the symptoms. The serum anti-acetylcholine receptor antibody level was 3.3 nmol/l; thus, myasthenia gravis was diagnosed. A chest roentgenogram revealed a left inferior mediastinal mass, and a chest computed tomographic scan revealed a fat density mass partly containing soft tissue areas in the left side of the anterior mediastinum. Median sternotomy and extended thymectomy were performed. The pathology examination of the tumor revealed mature adipose tissue including islands of thymic tissue containing Hassall's corpuscles, without germinal centers. The tumor was a thymolipoma of the anterior mediastinum. Her postoperative course was good, and she is doing well at 1 year postoperatively. The present study is the 15th reported case of thymolipoma associated with myasthenia gravis. We did not confirm a causal relationship between the thymolipoma and myasthenia gravis.     

Ectopic cystic thymoma associated with Raynaud's phenomenon.

Mediastinal cystic tumors are well-marginated round lesions that comprise 12% to 18% of all mediastinal masses. These lesions include a variety of diseases with overlapping radiologic appearances and variable prognoses. Pathological examinations are almost always required for differential diagnosis. We encountered a case of anterior mediastinal tumor discovered in the process of investigation of Raynaud's phenomenon. Taking into account the tumor location, a pericardial cyst was initially suspected. However, the tumor was surgically resected and histopathological examinations demonstrated thymus-like tissue in the cyst walls. Raynaud's phenomenon greatly improved after surgery. These findings suggested that cystic thymoma originated from ectopic thymic tissue and is accompanied by paraneoplastic syndrome.     

Microthymoma and microscopic thymomas associated with a thymic cyst without solid component

A 75-year-old asymptomatic man presented with an anterior mediastinal cyst without a solid component on computed tomography. Pathologic examination of the specimens obtained by thoracoscopic resection showed a thymic cyst with a 1.6-mm type A microthymoma in the surrounding thymic tissue. In addition, there were multiple hyperplastic nodules smaller than 1 mm histologically corresponded to microscopic thymomas. The patient underwent completion thymectomy through median sternotomy; thereafter, there was no residual thymic neoplasm detected. This was the first case report of a type A microthymoma. Microthymoma or microscopic thymoma could be present concomitantly with a thymic cyst without a solid component.     

Cosmetic approach to anterior mediastinal masses

A new approach for the removal of thymic tissue or any anterior mediastinal pathology is described. It uses a novel low U-shaped skin incision combined with a J-shaped upper mini-sternotomy. This technique was designed to provide wide exposure of the mediastinum and to be cosmetically appealing. Our study included 12 patients, 4 with a preoperative diagnosis of myasthenia gravis. There were no operative mortality and three complications. This procedure allows for complete removal of all thymic tissue under direct vision, and is less invasive that full sternotomy.     

Thymic Carcinoid Associated With Multiple Endocrine Neoplasia Syndrome Type I

Thymic carcinoids are a rare entity that may be associated with endocrine diseases like Cushing's syndrome or multiple endocrine neoplasia syndrome type I (MEN1). These tumors represent 4% of anterior mediastinal tumors and are characterized by their very aggressive behavior.We present the case of a patient with a previous MEN 1 diagnosis in whom, during the follow up of his disease, a thoracic image compatible with thymic carcinoid was detected. After an extended thymectomy that included peri-thymic fat resection, the clinical diagnosis was confirmed. A follow-up examination 14 months later revealed a suspicious lesion that suggested local recurrence, therefore the patient was reoperated on. The pathology report of this surgery indicated post-radiation fibrosis.Likewise, we present a review of the current diagnostic and therapeutic management of patients with MEN1 syndrome who are diagnosed with thymic carcinoid.     

Endoscopic robot-assisted extended thymectomy by subxiphoid approach with sternal lifting: Feasibility in the pig

Background In the search for novel approaches to thoracoscopic thymectomy we assessed the feasibility of a subxiphoid approach using computer-enhanced instruments and sternal lifting.Methods In 12 pigs, after lifting of the sternum, ports were placed subxiphoid (stereoscope) and in the left and right fourth intercostal space (instruments). Using computer-enhanced instruments, dissection of the thymus and anterior mediastinal fat pads was started at the diaphragm and continued cephalad.Results After setup of the robot system (23 ± 6 min, mean ± SD), the thymus, including both superior horns, and fat pads in the anterior mediastinum and cardiophrenic angles were dissected (109 ± 23 min), with excellent view of the phrenic nerves. Visual inspection after sternotomy after the procedure showed all thymic and fatty tissue was removed.Conclusions In the pig, endoscopic extended thymectomy can be safely performed by subxiphoid access using computer-enhanced instruments, sternal lifting, and three ports total.The abstract (abstract number 974) on this subject was accepted for poster presentation during the 11th International Congress of the European Association for Endoscopic Surgery in Glasgow, 15–18 June 2003     

Simultaneous double thymic carcinoids: a rare initial manifestation of multiple endocrine neoplasia type 1

A 53-year-old man was referred to our hospital for treatment of two anterior mediastinal tumors. The anterior mediastinal tumors were resected by thymectomy under the probable diagnosis of double thymomas. The final pathological diagnosis was multiple thymic carcinoids. Although 20%–25% of patients with thymic carcinoid have a family history of multiple endocrine neoplasia type 1 (MEN-1), radiographic screening just after the operation did not detect any endocrine tumors. However, the patient had a urinary calculus 4 months 7 months after the operation. Endocrinological examination then revealed mild hypercalcemia, hypophosphatemia, hyperinsulinemia, and hyperprolactinemia. Radiologically, a parathyroid tumor and a pancreatic tumor were found. The patient was referred to a university hospital and a mutation of MEN-1 gene was detected. The diagnosis of MEN-1 was confirmed about 1 year after the operation.     

Predictors of clinical outcome following extended thymectomy in myasthenia gravis.

OBJECTIVE: Thymectomy remains as the optimal treatment of choice in patients with myasthenia gravis (MG), however, the selection criteria for surgery remains controversial. METHODS: We examined the data charts of patients with MG underwent extended thymectomy. We investigated the possible correlations between the clinicopathologic features and clinical outcomes, and analyzed the data to clarify the effect of prognostic factors on clinical outcome. RESULTS: A total of 61 patients with a mean age of 35.8 +/- 12.2 years (range, 13-66 years) were analyzed. The overall improvement/remission and clinical worsening rates were 81.9 and 18.1%, respectively. Ossermann stage (P = 0.011) and presence of mediastinal ectopic thymic tissue (P = 0.007) showed a significant correlation with the clinical outcome. Multivariate analysis confirmed Ossermann stage (P = 0.0158), and presence of mediastinal ectopic thymic tissue (P = 0.0100) as independent predictors on clinical outcome. CONCLUSION: Ossermann stage and the presence of mediastinal ectopic thymic tissue are potential predictors on clinical outcome in patients with MG undergoing extended thymectomy.     

Multilocular Mediastinal Cyst with Rim Calcification: Report of a Case

We report a case of a multilocular anterior mediastinal cyst with rim calcification and severe adhesion to the adjacent organs. We excised the cyst completely, with resection of the left phrenic nerve, pericardium, and left lung because of the severe adhesion. Histological examination revealed that the multilocular cystic walls were composed of fibrous connective tissue and calcifications, but the lining epithelial cells were absent because of dystrophic calcification resulting from chronic inflammation. On the basis of the location and pathological findings, we diagnosed a multilocular mediastinal cystic tumor; most likely a multilocular thymic cyst. It is important to distinguish a multilocular thymic cyst from a unilocular thymic cyst because a multilocular thymic cyst may recur postoperatively and coexist with a thymic epithelial tumor. Dense adhesion to the surrounding mediastinal structures may make removal difficult, especially if there is rim calcification.