Ryoji Kawano

Micrometastasis to lymph nodes in stage I left lung cancer patients

BACKGROUND To evaluate the frequency and clinicopathological characteristics of lymph node micrometastasis in left lung cancer patients diagnosed to be stage IA and IB based on routine histopathologic examinations, we examined the lymph nodes in patients who had undergone an extended mediastinal lymphadenectomy, using immunohistochemical methods. METHODS Paraffin-embedded tissue sections from the lymph nodes in 49 patients with stage I left lung cancers were studied. We used AE1/AE3 as the anticytokeratin and Ber-EP4 as the antiepithelial cell antibodies when performing immunohistochemical staining. RESULTS We identified micrometastasis of the lymph nodes in 13 (26.5%) of 49 patients with stage I left lung cancer. NO disease was reclassified as N1 disease in 5 cases, N2 disease in 6 cases, and N3 disease in 2 cases. The location of the micrometastatic lymph nodes proved to be wide regions including the contralateral and highest mediastinal nodes, and 6 (46.2%) out of the 13 patients with micrometastasis were thus presumed not to be completely eliminated by a standard lymphadenectomy through an ipsilateral thoracotomy. The five year survival rate of patients with reclassified N1 to N3 disease was 74%, and the presence of micrometastasis was found to have no significant effect on the outcomes. CONCLUSIONS The micrometastatic involvement of the lymph nodes was both more frequent and extensive than expected even in stage I left lung cancer. These results suggest that an extended mediastinal lymphadenectomy may therefore be required for the locoregional control of stage I left lung cancer patients.

Mucinous adenocarcinoma of the thymus: A distinct variant of thymic carcinoma

BACKGROUND Primary thymic mucinous adenocarcinoma is a recently described subtype of thymic carcinoma, which behaves aggressively. METHODS The authors analyzed the clinical and pathological findings of three cases of thymic mucinous adenocarcinoma, and reviewed five cases previously reported in the English literature. RESULTS The patients were two males and one female between the ages of 38 and 55 years. Macroscopically, the tumors were mostly solid and white to yellowish-white. Areas with a gelatinous appearance were present. Histologically, all of the tumors were adenocarcinomas with abundant mucin production, which resembled the mucinous adenocarcinomas of other organs. Malignant tumor cells in nests, tubules and cribriform structures floated in pools of extracellular mucin. In one case, associated thymic cysts were found at the periphery of the tumor. The cyst wall was partially lined by malignant mucinous epithelium, which showed transition from benign thymic epithelium. Immunohistochemically, all of the tumors showed positive immunoreactivity for cytokeratin (CK) 20 and carcinoembryonic antigen (CEA). CD5 was diffusely positive in one case, and focally positive in the other two cases. The prognoses of these cases were extremely poor, and two of the patients died within 24 months. CONCLUSION Growing evidence suggests that mucinous adenocarcinoma is a distinct morphological variant of primary thymic carcinoma. We believe that clinicians and surgical pathologists should include thymic mucinous adenocarcinoma in the differential diagnosis of mediastinal adenocarcinoma.

Angiomyolipoma in the Lung Detected 15 Years After a Nephrectomy for Renal Angiomyolipoma

Angiomyolipoma is generally found in the kidney, but is especially rare in the lung. Nine cases of angiomyolipoma in the lung have been reported previously, and in 3 of these patients it was involved with nephrectomy for renal angiomyolipoma. The origination of the tumor was not completely recognized, but lymphangioleiomyomatosis and angiomyolipoma are known to have a common feature. The pathogenesis of angiomyolipoma in the lung has recently been researched in relation with lymphangioleiomyomatosis. We review these case reports of angiomyolipoma in the lung and discuss the clinical features and the generation of these tumors.

Langerhans cell histiocytosis: coexistence of bronchogenic and thymic cysts in the thymus.

Langerhans cell histiocytosis (LCH) is a disease caused by the proliferation of Langerhans cells in various tissues or organs. A 43-year-old male patient presented with an anterior mediastinal mass in the thymus. Histological examination after a thymectomy revealed a bronchogenic cyst in the thymus, and multiple LCH and small thymic cysts were also incidentally observed in the thymus. Unifocal LCH in an adult occurring in the thymus is extremely rare. Furthermore, no cases of LCH with the coexistence of bronchogenic and thymic cysts in the thymus have been previously reported.