Unencapsulated thymoma: a case report.

Thymomas, the most common mediastinal tumors, form capsules. Only a few reports have presented small thymomas without capsule formation, so-called microthymomas. Here, we report a case of an unencapsulated thymoma measuring 18 mm. A 42-year-old female presented with an anterior mediastinal tumor. Computed tomography revealed an 18-mm nodule in the anterior mediastinum. Magnetic resonance imaging revealed a solid tumor that was iso-intense on T1-weighted images and hypo-intense on T2-weighted images. Thoracoscopic partial thymectomy was performed. The histopathological diagnosis was a type B1 thymoma. The tumor was localized within the thymic tissue lacked a fibrous capsule and partially invaded the surrounding fat tissue. To our knowledge, this is the first report of an unencapsulated thymoma, except for microthymomas.

Primary pulmonary epithelioid sarcoma: a case report.

BACKGROUND: Epithelioid sarcoma most frequently occurs in the dermal or subcutaneous area of the distal extremities. To date, there have been three cases of primary pulmonary epithelioid sarcoma reported. We report a case of epithelioid sarcoma that is considered a primary lung tumor. CASE PRESENTATION: A 65-year-old asymptomatic Asian male patient underwent chest radiography during a routine health examination, and an abnormal mass was detected. His past medical history was unremarkable. He smoked 40 cigarettes every day and had slightly obstructive impairment on spirometry. He worked as an employee of a company and had no history of asbestos exposure. He underwent partial resection of the right lung by thoracoscopy. A histological examination of the tumor revealed a cellular nodule of epithelioid and spindle-shaped cells. Some of the tumor cells displayed rhabdoid features and reticular arrangement in a myxomatous stroma. Immunohistochemically, the tumor cells were positive for vimentin, smooth muscle actin (SMA), CD34, and epithelial membrane antigen (EMA); loss of the BAF47/INI1 protein in the tumor cells was also confirmed. A diagnosis of epithelioid sarcoma was established. Careful screening by whole-body positron emission tomography for another primary lesion after surgery did not detect any possible lesion. He had no cutaneous disease. CONCLUSION: To our knowledge, this is the fourth case of a proximal-type epithelioid sarcoma considered as a primary lung tumor.

[Multiple Minute Pulmonary Meningothelial-like Nodules;Report of a Case].

A 57-year-old woman was referred to our hospital for investigation of multiple tiny nodules in the lung fields bilaterally on computed tomography (CT). Video-assisted thoracoscopic lung biopsy was performed to diagnose the pulmonary lesions. Histological analysis showed nodular lesions with interstitial proliferation of uniform, round to oval cells with variable widening of the alveolar septa. Immunohistochemically, the cells were positive for EMA, CD56 and the progesterone receptor, but negative for chromogranin and synaptophysin. The diagnosis was "diffuse pulmonary meningotheliomatosis", with multiple diffuse "minute pulmonary meningothelial-like nodules". Diffuse pulmonary meningotheliomatosis should be kept in mind when we encounter small nodular shadows on a CT scan.

[Pancreatic Pleural Effusion;Report of a Case].

A 50-year-old man was admitted with respiratory failure. Chest X-ray and computed tomography revealed massive left pleural effusion and mediastinal shift. Pleural effusion showed abnormally high amylase levels of 42,600 IU/l and a high protein level of 3.2 g/dl. The serum amylase level was also 42,100 IU/l, and the proportion of pancreatic-type amylase was 88%. We diagnosed the patient with pancreatic effusion. Chest and abdominal enhanced computed tomography and magnetic resonance cholangiopancreatography revealed no pancreaticopleural fistula. He underwent a thoracoscopic examination that revealed brown pleural effusion as well as fibrin clots and thickness of the pleura. Histologically, there was no malignancy and the cause of pleural effusion was considered to be chronic pancreatitis.

Epithelial-myoepithelial carcinoma of the lung: a case report.

BACKGROUND: Pulmonary epithelial-myoepithelial carcinoma (P-EMC) is a rare subset of salivary gland-type tumors of the lung. Because of its rarity and unproven malignant potential, the optimal therapy for P-EMC has not been defined. Here, we report a typical case of P-EMC and a review of the literature to consider appropriate treatment. CASE PRESENTATION: A 54-year-old woman presented with an abnormal lung shadow on a routine chest X-ray. A chest computed tomography (CT) scan verified an 18-mm endobronchial nodule on the middle lobe. We performed a bronchoscopic biopsy, and the patient was diagnosed with P-EMC. After confirming the absence of tumors in the salivary glands, she underwent a right middle lobectomy along with hilar and mediastinal lymph node dissections. Currently, the patient is doing well, without any sign of recurrence 3 years after surgery. CONCLUSIONS: Although a majority of P-EMC cases, as in our case, behave indolently, several poor progression cases have been reported. For distinguishing the minor malignancy cases from others, histological findings such as myoepithelial anaplasia could be a predictive factor. Complete resection is needed to evaluate the whole tumor, because P-EMCs often show histological heterogeneity. Moreover, incomplete excision may be a poor prognostic factor. Although lobectomies as well as lymph node dissections, sleeve lobectomies, or pneumonectomies are routinely performed for complete resection, further investigation is required to establish the optimal treatment strategy.

Benign clear cell "sugar" tumor of the lung in a patient with Birt-Hogg-Dubé syndrome: a case report.

BACKGROUND: Birt-Hogg-Dubé (BHD) syndrome is a rare inherited autosomal genodermatosis and caused by germline mutation of the folliculin (FLCN) gene, a tumor suppressor gene of which protein product is involved in mechanistic target of rapamycin (mTOR) signaling pathway regulating cell growth and metabolism. Clinical manifestations in BHD syndrome is characterized by fibrofolliculomas of the skin, pulmonary cysts with or without spontaneous pneumothorax, and renal neoplasms. There has been no pulmonary neoplasm reported in BHD syndrome, although the condition is due to deleterious sequence variants in a tumor suppressor gene. Here we report, for the first time to our knowledge, a patient with BHD syndrome who was complicated with a clear cell "sugar" tumor (CCST) of the lung, a benign tumor belonging to perivascular epithelioid cell tumors (PEComas) with frequent causative relation to tuberous sclerosis complex 1 (TSC1) or 2 (TSC2) gene. CASE PRESENTATION: In a 38-year-old Asian woman, two well-circumscribed nodules in the left lung and multiple thin-walled, irregularly shaped cysts on the basal and medial area of the lungs were disclosed by chest roentgenogram and computer-assisted tomography (CT) during a preoperative survey for a bilateral faucial tonsillectomy. Analysis of the resected tumor showed large polygonal cells with clear cytoplasm proliferating in a solid pattern. Immunohistochemistry revealed that these tumor cells were positive for microphthalmia-transcription factor, S100, and CD1a but negative for HMB45, indicating that the tumor was a CCST. Genetic testing indicated that the patient had a germline mutation on exon 12 of the FLCN gene, i.e., insertion of 7 nucleotides (CCACCCT) (c.1347_1353dupCCACCCT). Direct sequencing of the FLCN exon 12 using genomic DNA obtained from her microdissected CCST cells clearly revealed loss of the wild-type FLCN sequence, which confirmed complete functional loss of the FLCN gene. On the other hand, no loss of heterozygosity around TCS1- or TSC2-associated genetic region was demonstrated. CONCLUSION: To our knowledge, this is the first report of CCST of the lung in a patient with BHDS, indicating that CCST should be added to the spectrum of pulmonary manifestations of BHDS.

[Mediastinal cystic lymphangioma; report of a case].

A cystic lymphangioma is a rare mediastinal benign tumor. A 38-year-old male was referred to our hospital because of an mediastinal mass incidentally detected on chest X-ray. The mass had enlarged rapidly during the course of 1 year. Computed tomography (CT) of the chest showed a 7 cm well defined cystic tumor in the left anterior mediastinum. Magnetic resonance imaging (MRI) demonstrated a mass with heterogeneous high signal intensity on enhanced T2-weighted images. The cystic tumor, localized in the mediastinal adipose tissue, was completely resected by a thoracoscopic procedure. A pathological examination confirmed the diagnosis of a cystic lymphangioma.

Arteriovenous hemangioma in the middle mediastinum: report of a case.

Hemangiomas in the mediastinum are uncommon, and the majority of these tumors are located in the anterior mediastinum. The present report describes an extremely rare case of a hemangioma in the middle mediastinum. A 40-year-old male patient presented with a mass in the left lower lung field on radiographic screening. Chest computed tomography and magnetic resonance imaging revealed a mass measuring 2.5 cm in diameter, which was close to the descending aorta in the left middle mediastinum. The tumor resection was performed by video-assisted thoracic surgery. The thoracoscopic findings revealed a blackish brown mass with a capsule, which had not invaded the descending aorta or cardiac sac. Histologically, the tumor was composed of typical thick-walled vessels and was therefore classified as an arteriovenous hemangioma.

Pleuropulmonary paragonimiasis with intrathoracic mass.

Pleuropulmonary paragonimiasis is a food-borne parasitic disease caused by the lung fluke Paragonimus westermani or other species of Paragonimus, which is endemic in Southeast Asia. It presents mainly pleural effusion or intrapulmonary nodules with respiratory symptoms. However, here we describe an exceedingly rare case of Paragonimus westermani with a mass in the pleural cavity. A 47-year-old man, who had presented with chest pain nine months earlier, was found to have right pleural effusion on detection survey computed tomography. He had a history of asbestos exposure and river fishing as a hobby and was confirmed to have Paragonimus westermani by immunodiagnosis. Because of a high level of hyaluronic acid in pleural effusion, he underwent a thoracoscopic examination. The pleura of the thoracic wall thickened greatly and showed no malignant lesion on biopsy. A white mass measuring 8 cm in diameter showed in the pleural cavity, which partially connected with the diaphragm and pulmonary pleura of the lower lobe. The postoperative pathological examination reported that the intrathoracic mass was a lesion that contained necrotic tissue enveloped with a fibrin capsule, which was thought to be formed by paragonimus.

[Impact of cimetidine on growth and metastasis of surgically transplanted Lewis lung cancer].

PURPOSE: Histamine has multiple biological functions and its immunomodulatory actions are not fully understood. In the current study, we investigated the effect of cimetidine, which is a histamine-2 receptor antagonist, on the progress of transplanted Lewis lung cancers using a mouse model. METHODS: A piece of Lewis lung cancer weighing 15 mg was transplanted into the subcutaneous space on the back of each C 57 BL/6 mouse. Mice were randomized into a no-treatment control group (CO) or one of two treatment groups. In the treatment groups, 16 mg/kg/day (LD) or 160 mg/kg/day (HD) of cimetidine was orally administered from one week before the day of transplantation to the time of sacrifice. Subcutaneous tumors and lungs were excised on the 28th or 42nd postoperative day. RESULTS: The mean vascular densities of the subcutaneous tumors on day 28 were 55.7 +/- 23.9/mm2 in CO, 88.0 +/- 16.3/mm2 in LD and 122.6 +/- 16.9/mm2 in HD (p < 0.05; CO vs. LD or HD, LD vs. HD). On day 42, mean weights of the subcutaneous tumors and the numbers of metastatic lung tumors were 6.0 +/- 2.1 g in CO, 7.9 +/- 1.2 g in LD and 10.0 +/- 1.9 g in HD (p < 0.05; CO vs. HD), and 7.5 +/- 6.0 in CO, 17.0 +/- 3.0 in LD and 19.8 +/- 7.4 in HD (p < 0.05; CO vs. HD), respectively. CONCLUSIONS: These results suggest that cimetidine dose-dependently enhances the angiogenesis, growth and metastasis of surgically transplanted Lewis lung cancer in a mouse model of this type.

[Minute pulmonary meningothelial-like nodules: a case report].

The presence of multiple small nodular shadows on a routine chest radiograph was noticed in a 56-year-old woman who had undergone a left mastectomy on the diagnosis of breast cancer 8 years before. Chest CT films revealed small nodules scattered beneath the pleura mainly in both lower lobes. A biopsy was performed during video-assisted thoracoscopy to rule out metastasis from breast cancer. Biopsy specimens showed spindle--or oval-shaped cells arranged in nests associated with a dedicated network of capillaries. These findings were compatible with minute meningothelium-like nodules (MN). The pathogenesis of MN is still unknown. It is common in elderly women, and the prognosis is excellent without any treatment. MN is an important disease in the differential diagnosis of multiple nodular shadows found on chest CT.