Cystic thymoma without solid mass lesions on diagnostic imaging —A case report—

A 68-year-old man was referred to our hospital because of an abnormal shadow on a chest X-ray film. A chest CT scan snd MRI demonstrated a cystic mass without solid lesions on the anterior mediastinum. The CT scan also showed that it was a well-defined and homogenous mass without contrast enhancement effect. ⁶⁷Ga and ²⁰¹T1 scintigrams showed no uptake in the mass. Needle aspiration cytology was performed, and there was no evidence of neoplasms. A thymic cyst was diagnosed, and then an operation was performed. At the operation, the cystic tumor was removed along with thymic tissues by a median sternotomy. On the cut section of the resected specimen, the tumor was found to be a cyst with small solid nodules on the wall. Pathologic examination revealed that the tumor was a cystic thymoma. We consider that patients with cystic tumors on the onterior mediastinum should obtain histopathologic diagnosis because of the difficulty in excluding neoplasms such as thymoma.     

Thymoma arising in a thymic cyst.

We present a case of thymoma arising in the wall of the thymic cyst. A 77-year-old asymptomatic woman demonstrated an approximately 3.5 cm sized cystic mass in the left anterior mediastinum in the CT scan. The tumor was extirpated by a total thymectomy. Histologically, the cyst wall was lined by low cuboidal cells, but a markedly thickened wall was observed at the upper site of the mass, which was found to be thymoma. These findings may suggest that the thymoma originated from the wall of the thymic cyst.     

Mediastinal hematoma due to thymoma hemorrhage--a case report

A 70-year-old man came to our hospital complaining mainly of acute dyspnea. A chest X-ray, echocardiogram, and chest CT showed a mediastinal mass, and pericardial and pleural effusions. A thoracotomy revealed a cystic tumor along the thymus. The tumor contained bloody fluid, coagula, and fibrin calculi. Rapid specimens showed no tumor cells and the hematoma was assumed to have been caused by the thymus. Therefore, a thymectomy was performed and as much of the hematoma as possible was removed. After the operation, a careful pathological examination revealed a thymoma with a diameter of about 7 mm. In addition, coagula and fibrin calculi contained some tissue from the thymoma, and the diagnosis was made that a mediastinal hematoma had formed due to hemorrhage from the thymoma. Several cases of mediastinal tumor of cyst hemorrhages in the thorax have been reported. However, only a few cases of thymomal hemorrhages in the thorax have been reported; one case each of mediastinal hematoma, hemothorax, and cardiac tamponade. Great care is necessary when dealing with atraumatic mediastinal hematomas if malignant tumors such as thymoma are present.     

Invasive thymoma with thymic cyst; report of a case

A 27-year-old woman was pointed out an abnormal shadow on chest X-ray in 1999. Because of the enlargement of the chest abnormal shadow, she was admitted to our hospital in 2000. Chest computed tomography (CT) revealed anterior mediastinal solid mass with cystic lesion. A thymoma was suspected. The tumor was removed in June 2000, through a longitudinal incision of the sternum. There was a severe adhesion between the tumor and the right brachiocephalic vein. Histological examination revealed a thymoma with thymic cyst. The thymoma had a capsular invasion (stage II). There were few reports for cases of thymoma with thymic cyst.     

A case of pericardial cyst associated with atrial septal defect

A 51-year-old woman with an abnormal shadow in the right upper mediastinum and systolic heart murmur was diagnosed as mediastinal cyst and atrial septal defect (ASD). Before the operation, the cyst was suspected as bronchogenic cyst or cystic thymoma based on the findings by CT and NMR. Both cystectomy and closure of ASD was successfully performed and the cyst was diagnosed as pericardial cyst by pathological examination. A brief of literature on the pericardial cyst is given.     

Renal cell carcinoma in a renal cyst--observation of changes during the year: report of a case]

We report a case of renal cell carcinoma within a renal cyst. A 45-year-old man visited our hospital with the chief complaint of left back pain. Ultrasonography was examined by a physician, and it revealed a right renal cyst by chance. Computed tomography demonstrated a thick wall in the cyst which showed enhancement of density with contrast medium. The physician followed the cystic lesion periodically, by ultrasonography and computed tomography. The cyst on volume did not change, but the thick wall had a tendency to develop to inner space. The patient was referred to our department. Angiography was performed, and it showed neovascularity and tumor staining. We diagnosed the renal tumor in a renal cyst. Transabdominal right radical nephrectomy was performed on 18 June, 1991. The resected specimen involved a mall tumor (2.5 x 2.0 cm) in the cyst. Histological examination of the tumor was renal cell carcinoma which was well capsulated by connective tissue without invasion to normal parenchyma and perirenal fat. We speculated that the renal cell carcinoma originated from the cyst wall and it developed to inner cystic space. The natural history of the renal cell carcinoma in a renal cyst is not clear. Our case shows a type of its history. We reviewed and discussed the types and diagnosis of the renal cell carcinoma in a renal cyst.     

Primary thymic adenocarcinoma coexisting with type AB thymoma: a rare case with long-term survival

Thymic carcinoma is a rare tumor. The most common histological subtype is squamous cell carcinoma, and only a few cases of thymic adenocarcinoma have been reported. A case of papillary adenocarcinoma of thymic origin that coexisted with type AB thymoma as a separate nodule is presented herein. The patient was found to have an abnormal mediastinal shadow on chest X-ray. A computed tomography scan revealed a round, 6.5-cm-diameter mass in the right anterior mediastinum. The preoperative diagnosis was thymoma, and thymothymectomy was performed. On pathological examination, two tumors, which were diagnosed as papillary adenocarcinoma and type AB thymoma, respectively, were present in the thymus without any connection with each other. The patient has been alive without any signs of recurrence for 11 years after surgery. We diagnosed the adenocarcinoma in this case was a primary thymic carcinoma.     

Cyst formation of meningioma: report of two cases and review of literature

Cystic meningioma is rare and said to account for 1 to 2% of all types of meningioma. Here we report two cases of cystic meningioma. Case 1 is a 25-year-old man. He had suffered from sporadic epileptic seizure for about two years until the first CT was performed. It revealed a large cystic lesion at the right parietal region in touch with the midline structure. A nodular high density area was delineated in the contrast enhanced CT on the medial wall of the cyst. He showed no neurological abnormality at all. Case 2 is a 56-year-old female who had been complaining of memory disturbance, and an episode of sudden dizziness followed by a syncope that lasted for a few minutes. Neurological examination revealed slight right hemiparesis, right homonymous hemianopsia and left papilledema. A large cystic lesion was delineated at the temporal region in the plain CT, and no positively enhanced region could be found in the contrast enhanced CT. After surgical removal of the tumors, both cases were identified as cases of meningioma. They were diagnosed histopathologically as a fibroblastic meningioma and a meningotheliomatous meningioma respectively. The wall of the cyst consisted of the cortical surface per se in both cases. Preoperative diagnosis of such cases and the mechanism by which the cyst is formed were also discussed.     

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.     

Spontaneous regression of thymoma; report of a case

A 44-year-old woman was admitted to our hospital with chest pain. Chest roentgenograms and computed tomography (CT) scan revealed an anterior mediastinal tumor and bilateral pleural effusion. However, CT scan 3 days after magnetic resonance imaging (MRI) revealed regression of the tumor. Extended thymo-thymectomy was performed via median sternotomy. The tumor was in the right lobe of the thymus. Pathologically the tumor was diagnosed as a mixed type non-invasive thymoma, but some parts of the tumor cells were necrotic. This is the 10th case of spontaneous regression of thymoma reported in the Japanese literature.     

Heterotopic gastrointestinal mucosa and pancreatic tissue in a retroperitoneal tumor

We believe that this is the first report of a retroperitoneal tumor consisting of heterotopic gastrointestinal mucosa and pancreatic tissue. The patient was a 19-year-old woman with the chief complaint being occasional back pain. Abdominal computerized tomography demonstrated a 3.1 × 2.5 × 3.2-cm low-density solid and cystic lesion adjoining the left renal vein between the aorta and inferior vena cava. Angiography revealed that the inferior vena cava was displaced by the hypovascular tumor. The retroperitoneal lesion was diagnosed preoperatively as a benign tumor such as a neurogenic neoplasm or lymphangioma. At laparotomy, a cystic tumor was found, which existed behind the inferior vena cava and renal vessels, and contained reddish-brown fluid, suggesting hemorrhage in the past. The cut surface of the tumor showed a unilocular cyst with partially hypertrophic wall. Histopathological examination revealed a cystic tumor lined with heterotopic gastric and duodenal mucosa, with pancreatic tissue in the muscularis propria. In addition, evidence of bleeding from the gastric mucosa was observed in the cystic tumor. External secretion from these tissues could have triggered the hemorrhage and expanded the tumor, possibly resulting in the back pain.     

Laparoscopic resection of an intradiaphragmatic bronchogenic cyst

BACKGROUND: A 43-year-old woman with recurrent hiccup and discomfort in the right upper abdomen was diagnosed by computed tomographic (CT) scan with a cystic tumor in the right liver. Echinococcus serology was negative. METHODS: A laparoscopic procedure was chosen as standard therapy for symptomatic cystic liver tumors. The presumed tumor turned out to be a diaphragmatic cyst 8 cm in diameter at the center of the right hemi-diaphragm. By using the ultrasonic device, the cystic tumor was completely and safely removed from the diaphragm. The defect was closed by using nonabsorbable sutures. A chest drain was inserted for 1 day. RESULTS: The postoperative course was uneventful, and the patient was discharged on day 4. The histopathological examination revealed a bronchogenic cyst. No recurrence was noted by CT-scan after 12 and 24 months. CONCLUSIONS: Due to this rare diagnosis, the intradiaphragmatic location of a bronchogenic cyst is difficult to identify with radiological methods. Complete surgical excision is the treatment of choice. The conventional surgical approach is a posterolateral thoracotomy. In the literature, video-assisted thoracoscopic surgery (VATS) has been described as a safe and effective procedure. In our case, we could demonstrate that the laparoscopic excision of a cyst including partial diaphragmatic resection can be done safely in a diaphragmatic location with all the advantages of minimally invasive surgery.     

Usefulness of power Doppler ultrasound in a patient with renal cell carcinoma in the wall of a simple renal cyst]

We present a case of renal cell carcinoma in the wall of a simple renal cyst. A 54-year-old man visited our hospital with a complaint of right back pain. Ultrasound study revealed right hydronephrosis, a ureteral stone, and a 9 x 8 cm renal cyst, with a tumor, 2 cm in diameter, in the cyst wall. Power Doppler Ultrasound and enhanced computed tomography demonstrated hypervascularity of the tumor. Clinically, he was diagnosed as renal cell carcinoma and nephrectomy was performed. Pathological findings of the tumor showed clear cell carcinoma in the wall of a simple renal cyst. Twelve months after the nephrectomy, he was free from recurrence.     

Hemangioma in the anterior mediastinum

Anterior mediastinal hemangiomas are very rare neoplasms in mediastinal tumors. A 58-year-old woman was revealed to have a mass measuring 4×3 cm in size in the anterior mediastinum with calcification on computed tomography. It was initially suspected to be a thymoma. We performed tumor extirpation in November 1998. The tumor was close to the thymus and slightly adhered to the superior vena cava, ascending aorta and right phrenic nerve, however, it did not invade any surrounding organs. Histopathologically, it was diagnosed to be a venous type hemangioma composed of vessels covered by smooth muscle and a cavernous type hemangioma composed of dilated vessels covered by one layer of endothelial cells.     

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.     

Retrorectal epidermoid cyst in an elderly woman: Report of a case

An epidermoid cyst is a common occurrence in the skin. Such a cyst occurring in the retrorectal space, however, is extremely rare. We herein present a case of retrorectal epidermal cyst in a 67-year-old Japanese woman. She reported no symptoms and a perirectal mass behind the lower rectum was accidentally detected by computed tomography (CT). Contrast CT and magnetic resonance imaging revealed a cystic mass (76 x 70 x 63 mm) with a slightly enhanced thin wall which was attached to the lower rectum. The patient underwent surgery via a posterior approach. The mass was exposed after an excision of subcutaneous fat and was firmly adhered to the anal sphincter muscle. The cystic mass was completely removed without a proctectomy. Histologically, the cyst was diagnosed to be an epidermoid cyst. The postoperative course was uneventful, and the patient was discharged on postoperative day 9. A diagnosis of retrorectal cystic tumor is difficult, and a complete resection is necessary for the treatment of such tumors.     

Papillary cystadenocarcinoma of the prostate

A giant cystic formation was found behind the prostate of a 69-year-old man who presented with urinary retention. Ultrasonography, computed tomography scans and magnetic resonance imaging revealed a large cystic intrapelvic mass and biopsy of the cyst wall diagnosed papillary cyst adenocarcinoma. Immunohistochemically, the tumor originated from the prostate.     

A case report of a paraesophageal bronchogenic cyst and an esophageal cyst]

There are relatively few paraesophageal bronchogenic and esophageal cysts in mediastinal tumors. It is often difficult to distinguish between these cysts. Case 1: 11 year old, male with no symptoms. An abnormal tumor shadow was revealed by chest roentgenogram. Before operating, CT, MRI and other laboratory tests were suggested that the tumor was neurogenic. A cyst with a pedicle connected to the esophageal muscle layer was found during the operation. Pathological examination confirmed a bronchogenic cyst lined with cartilage. Case 2: 38 year old female with epigastralgia. Upper gastrointestinal series revealed that the thoracic esophagus was smoothly compressed from the outside. CT and MRI showed a well-defined cystic mass in the posterior mediastinum. The cyst bordered the esophagus, but there was no direct communication between them. The pathological findings showed the presence of a double layer of smooth muscle without cartilage which was diagnosed as an esophageal cyst.     

Atypical meningioma with large cyst. Case report

A 29-year-old male presented with loss of consciousness and generalized seizure, followed by right hemiparesis and speech disturbance. Computed tomography and magnetic resonance imaging showed a solid, enhanced tumor with a cyst in the left frontal area with surrounding edema and mild mass effect. The cyst wall was also enhanced. The preoperative diagnosis was cystic falx meningioma. The tumor was totally resected, but most of the cyst wall adhered tightly to the surrounding brain and could not be removed. Histological examination revealed atypical meningioma and tumor cells in the cyst wall. The patient received local radiotherapy to the residual cyst wall with a total dose of 50 Gy.     

A case of fistula between the urinary bladder and an ovarian dermoid cyst

A 20-year-old woman was referred to our hospital for further evaluation on persistent pyuria. Physical examination showed a tender solid suprapubic mass. Computed tomography showed a right ovarian multilocular cystic tumor just above the urinary bladder. Cystoscopy showed pus leakage from an orifice in a hemisphere protrusion of the bladder wall. A small catheter could be inserted into the orifice. It revealed a fistula 4 cm in length between the right ovarian tumor and the vesical cavity. The tumor and the adjacent thickened bladder wall with an abscess and fistula were resected en bloc. Also a small left ovarian cyst was enucleated. Histopathological examination showed bilateral ovarian dermoid cysts, abscess formation, and marked inflammatory change around the fistula in the vesical wall. The fistula was thought to be the consequence of infection of the ovarian cyst.