[A Case of Carcinoma Showing Thymus-Like Differentiation (CASTLE) of the Thyroid].

The case presented herein was a 70-year-old woman who had no compliant, but had a mass in the lower part of the right lobe of the thyroid detected by ultrasound (US). The US image of the tumor, measuring 13 mm in diameter, showed a low and heterogeneous internal echo level with calcification and an irregular margin. The tumor appeared to extend to the adjacent sternothyroid muscle, and cervical lymph node swelling was detected in a computer tomography (CT) image, but no metastatic lesion was found by positron emission tomography (PET)-CT. In a fine needle aspiration cytology of the tumor, papillary thyroid carcinoma was suggested because of the atypical epithelial cells having some changes other than intranuclear inclusion bodies. A subtotal thyroidectomy and central neck lymph node dissection were performed. The excised tumor was histologically composed of irregular nests or sheets of atypical squamoid epithelial cells with some ductal structures that leached to the sternothyroid muscle and involved the right lower parathyroid gland. Carcinoma showing thymus-like differentiation (CASTLE) was diagnosed histopathologically and immunohistochemically with the following immunohistochemical results: Cluster of differentiation 5 (CD5) (+), tumor protein p63 (p63) (+), KIT proto-oncogene receptor tyrosine kinase (c-KIT(CD117)) (+), thyroglobulin (-), and thyroid transcription factor-1 (TTF-1) (-). CASTLE is a rare carcinoma of the thyroid that architecturally resembles thymic epithelial tumors. Many CASTLE patients have been misdiagnosed as other carcinomas, such as anaplastic carcinoma, poorly differentiated carcinoma or squamous cell carcinoma of the thyroid. Immunohistochemical examination, including CD5 played an important role in the final diagnosis of CASTLE, although the distinction from diagnosis as squamous cell carcinoma or mucoepidermoid carcinoma in Hematoxylin-Eosin staining was challenging in our case. Nodal metastasis and perithyroidal tumor extension of CASTLE can predict its worse prognosis. Thus, at least careful follow-up studies are mandatory in cases of CASTLE.

A Case of Matrix-Producing Carcinoma of the Breast.

A 61-year-old woman was referred to our hospital because of a right breast mass. A 19 mm hard mass was palpable in the A area of the right breast. A contrast-enhanced MRI showed rim enhancement at the peripheral region of the tumor, which was thought to represent the carcinoma component mainly at the periphery and the matrix component inside the tumor. A low density mass with rim enhancement at the peripheral region was observed in a contrast-enhanced CT, the same as in the MRI. Neither axillary lymph node metastasis nor distant metastasis was observed. A core needle biopsy of the tumor lead to a diagnosis of matrix-producing carcinoma (MPC). A breast-conserving mastectomy with sentinel lymph nodes biopsy was performed on the right breast MPC (T1c, N0, M0 Stage I). Histopathologically, the tumor demonstrated overt carcinoma with direct transition to a cartilaginous or osseous matrix and lacked an intervening spindle cell component. Immunohistochemistry showed estrogen receptor (ER) (-), progesterone receptor (PgR) (-), human epidermal growth factor receptor 2 (HER2) (-), and Ki67 index of 50%, so-called triple negative breast cancer. The tumor was also positive for SRY-related HMG box-9 (SOX9), which is a useful marker of chondroid differentiation in normal and neoplastic tissues. The patient lived free from recurrence for 5 years, even though her adjuvant therapy was only radiation therapy without adjuvant chemotherapy. MPC is an uncommon and relatively rare variant of metaplastic carcinoma, and the prognosis for patients with MPC is poorer than that for patients with ordinary breast cancer. Here we report a case of MPC of the breast with characteristic rim enhancement in contrast-enhanced MRI and CT. The intrinsic subtype and prognosis of MPC is controversial, and then we may need more experience with MPC cases.

[A case of low grade ductal carcinoma in situ of the breast with difficulties in making the preoperative diagnosis after detection by FDG-PET].

A 56-year-old woman underwent FDG-PET screening, which demonstrated delayed-phase uptake in the lower part of the left breast. The findings of mammography, ultrasonography, MRI and cytological examination were compatible with ductal carcinoma in situ (DCIS), but core needle biopsy showed no evidence of malignancy. Therefore, partial resection of the left breast with sentinel lymph node biopsy was performed to make a definite diagnosis. Histological examination showed that this tumor was low grade DCIS. FDG-PET is a very useful examination to detect malignant diseases, but it is quite difficult to distinguish them from benign ones. It is suggested that delayed-phase uptake of FDG-PET is useful for diagnosis of DCIS.

The enhancement of preproendothelin-1 synthesis and the acceleration of endothelin-1 processing in the acute hypoxic rat aorta.

Wistar rats were deeply anesthetized and perfused by Hanks' solution bubbled with either 95% air and 5% CO2 (normoxic group) or 95% N2 and 5% CO2 (hypoxic group) from the thoracic aorta for 30 minutes. The isolated abdominal aortas were used for electron microscopy, immunocytochemistry of endothelin-1 (ET-1) and endothelin-converting enzyme-1 (ECE-1), and in situ hybridization of preproendothelin-1 mRNA. A remarkable increase in the number of Weibel-Palade bodies, storage sites of ET-1 and ECE-1, occurred in the hypoxic group when compared with the normoxic group. Immunoreactivities for ET-1 and ECE-1, and signals for preproendothelin-1 mRNA were seen along the endothelia of both groups, but the intensities were significantly elevated in the hypoxic group. The increase in the number of ECE-1 immunoreactive gold particles was noticed in Weibel-Palade bodies in the hypoxic group. These findings indicate the enhancement of preproendothelin-1 synthesis in the rat aortic endothelial cells and the acceleration of ET-1 processing in Weibel-Palade bodies of such cells in an acute hypoxic condition.

Increased immunoreactivities against endothelin-converting enzyme-1 and monocyte chemotactic protein-1 in hepatic stellate cells of rat fibrous liver induced by thioacetamide.

The progression of rat liver fibrosis induced by intraperitoneal administration of thioacetamide (TAA) was evaluated by immunocytochemistry using anti-alpha-smooth muscle actin (alpha-SMA), antiendothelin-converting enzyme (ECE)-1, and anti-monocyte chemotactic protein (MCP)-1 antibodies. The fibrous septal spaces gradually increased after administration of TAA, and pseudolobules were established in the 7-week TAA-treated groups. Immunoreactivities against alpha-SMA were not detected in hepatic stellate cells (HSCs) of the control group without TAA treatment, although they were observed in the HSCs around the fibrous septal spaces in all TAA-treated groups, indicating that activation of HSCs occurs during the establishment of pseudolobules. Immunoreactivities against ECE-1 and MCP-1 were seen in such HSCs of the TAA-treated groups, but few or no immunoreactivities were detected in the HSCs of the control group. The most significant increase in the ECE-1 immunoreactivities was detected in the 1-week TAA-treated group, whereas that in MCP-1 was observed in the 7-week TAA-treated group. The present immunocytochemistry indicated a difference in the accelerated expression period between immunoreactivities against ECE-1 and MCP-1 in the HSCs during the progression of TAA-induced liver fibrosis, suggesting that ECE-1 is involved in the early phase of liver fibrosis and that MCP-1 plays a role during the later phase.