ABSTRACT Epithelial‐mesenchymal transition (EMT) plays a crucial role in carcinogenesis, including mesothelioma. D‐Meso‐Sonobe is a deciduoid‐type mesothelioma cell line with morphological features similar to those of epithelioid cells. Here, we report that D‐Meso‐Sonobe cells exhibit spindle cell mesenchymal features under continuous confluent culture conditions. The spindle cell mesenchymal D‐Meso‐Sonobe expresses zinc finger E‐box‐binding homeobox 1 (Zeb1), which is a master regulator of EMT in the nucleus. Xenoplanted D‐Meso‐Sonobe cells expressed nuclear Zeb1 and yes‐associated protein at the cancer invasion front and focally expressed integrin subunit alpha V and actin alpha 2, which are molecular phenotypes acquired by EMT in mesothelioma. Subsequent RNA sequencing revealed that lysyl oxidase like 1 (LOXL1) was more highly expressed in cultured spindle mesenchymal D‐Meso‐Sonobe cells than in epithelioid cells. LOXL1 immunoreactivity was observed at the invasive front of xenoplanted D‐Meso‐Sonobe cells. The epithelial‐mesenchymal plasticity of D‐Meso‐Sonobe cells may be applicable for the development of candidate molecular agents targeting EMT in mesothelioma.

ABSTRACT Atypical lipomatous tumor/well‐differentiated liposarcoma is a locally aggressive mesenchymal neoplasm composed of adipocytes and stromal cells. Gastric cases are exceedingly rare, and their malignant potential remains unclear. We report a case of a woman in her 60s who was found to have multiple submucosal tumor‐like lesions of the stomach. Over time, the tumors increased in size, requiring a laparoscopic partial gastrectomy. Histological examination revealed a tumor composed of both fatty tissue and fibrous stroma with nuclear atypia. Immunohistochemistry showed positivity for CDK4 and MDM2, and fluorescence in situ hybridization confirmed MDM2 amplification, leading to a diagnosis of atypical lipomatous tumor/well‐differentiated liposarcoma. This case presented an unusual gastric manifestation, with multiple submucosal tumor‐like lesions on endoscopy and exhibiting progressive morphological changes over several years.

Herein, we report a rare case of pleural epithelioid malignant mesothelioma with a prominent myxoid stroma. To date, detailed morphological or molecular pathological findings have not been reported for this type of tumor. Hence, we aimed to describe the cytological, histological, immuno-cytohistological, electron-microscopic, and molecular pathological findings using fluorescence in situ hybridization (FISH) in such a case. The patient was a male in his mid-sixties with a history of asbestos exposure and had originally visited the hospital with a persistent cough and fever. Chest radiography revealed left pleural effusion, and laboratory examination revealed a high titer for hyaluronic acid in the effusion. Additionally, computed tomography revealed diffuse multinodular or cystic lesions in the left parietal pleura, and pleural effusion cytology revealed large epithelioid cells with mild nuclear atypia, which were considered reactive mesothelial cells. Cytologically, Giemsa staining revealed that these cells harbored variously sized intracytoplasmic vacuoles that were Alcian-blue-positive, suggesting hyaluronan production. Biopsy revealed large epithelioid cells that loosely proliferated against a prominent myxoid background. These cells were immuno-positive for calretinin, Wilms' tumor 1, D2-40, vimentin, and cytokeratin AE1/AE3 but not for carcinoembryonic antigen, Ber-EP4, or desmin. BRCA 1 associated protein 1 immunostaining showed nuclear loss, and FISH showed homozygous deletion of cyclin-dependent kinase inhibitor 2A (p16) on chromosome 9p21. Based on these findings, the lesion was diagnosed as an epithelioid mesothelioma with a prominent myxoid stroma. Electron-microscopy demonstrated a dense microvillus pattern on the surface of the tumor cells, indicating a mesothelial cell origin, and variously sized vacuoles in the cytoplasm, confirming the presence of intracytoplasmic vacuoles demonstrated on cytology. The tumor tissues obtained during surgery harbored prominent myxoid stroma, which proved that the present tumor was consistent with this type of mesothelioma. After informed consent was obtained, the patient and family wished for total resection of the tumor and postoperative chemotherapy, and the patient eventually died eight months after surgery.

Sacral schwannoma is a rare tumor with relatively few symptoms; it thus tends to be large at diagnosis and is challenging to treat surgically. We present the case of a 12-year-old girl with a large sacral schwannoma that was successfully surgically resected using O-arm navigation in a two-stage operation. First, we performed tumor resection from the posterior aspect with assisted O-arm navigation. One week later, resection from the anterior aspect was conducted with posterior spinopelvic fixation and fibula graft. We performed partial resection of the tumor from the anterior and posterior aspects as much as possible. O-arm navigation contributed to precise and safe tumor resection and implant insertion.

Background This study explored the assessment of intrathoracic lymph node metastasis by 18F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography computed tomography (PET/CT) in patients with asbestos-related lung cancer (ARLC). Methods We retrospectively reviewed the data on 35 patients with ARLC who underwent preoperative FDG-PET/CT and surgical resection between January 2012 and December 2018. We collected medical information from medical records and imaging systems and examined the FDG uptake in each lymph nodal region resected by surgery and the presence or absence of pathological lymph node metastasis. Results Pathological lymph node metastases were detected in 14 (8.70%) of 161 nodal stations. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of FDG-PET/CT were 71.4% (10/14), 87.8% (129/147), 35.7% (10/28), 97.0% (129/133), and 86.3% (139/161), respectively. Six of the eight false-positive patients had bilateral accumulations, whereas all six true-positive patients had unilateral accumulation (P=0.006). On histopathological examination, the false-positive nodes showed disruption of lymphoid follicles in the cortex, infiltration of histiocyte-like cells in the medulla, fibrous micronodules, and severe anthracosis. Conclusions PET/CT scans of patients with ARLC showed comparable sensitivity and specificity to those of PET/CT scans of patients with conventional lung cancer reported in the literature. Many false-positive cases also showed bilateral symmetric accumulation. This method can be used to evaluate lymph node involvement in lung cancer.

The first case is a 62-year-old female who complained of painful left axillary lymph node swelling. Six months later, a CT scan revealed multiple lung nodules. Biopsies of the axillary lymph node and lung showed metastatic carcinoma from breast cancer. However, no breast tumor was found. She was diagnosed with occult breast cancer with metastasis to the axillary lymph node and lung. ER(+), PgR(±), HER2(1+). Letrozole was administered, and effective control was achieved for 20 months. The second case is a 62-year-old female who presented with back pain. A CT scan revealed left axillary lymph node swelling and multiple osteolytic changes in the thoracolumbar spine and rib. Biopsies of the axillary lymph node and thoracic spine showed metastatic carcinoma from breast cancer. However, no breast tumor was found. She was diagnosed with occult breast cancer with metastasis to the axillary lymph nodule and bone. ER(+), PgR(+), HER2(1+). Fulvestrant and denosumab were administered. However, after 6 months, she discontinued the treatment. Our results suggested that effective control could be achieved through systemic therapy and local therapy was not necessary for Stage Ⅳ occult breast cancer.

A 66-year-old woman underwent distal gastrectomy because of gastric cancer(stage ⅠB)and received no adjuvant chemotherapy. Eight years after the operation, computed tomography showed a small nodule in the right breast. Mammography did not reveal any abnormalities. Ultrasound sonography showed a diffuse and gradual non-mass-like low echoic lesion. Core needle biopsy indicated a malignancy. Partial resection of the right breast was performed to obtain a diagnosis. On postoperative histopathological examination, signet-ring cells were found in the tumor, and immunohistochemical analysis showed that both the breast tumor and the gastric carcinoma were MUC5AC-positive and MUC1-negative. We diagnosed this breast tumor as metastasis from gastric cancer. The patient has received chemotherapy with no subsequent metastatic tumors, and good control has been achieved for 21 months after the detection of the breast metastasis.

This case was observed in a man in his 70s. Although symptomatic treatment was performed for epigastralgia, endoscopic examination revealed a type 3 tumor on the fornix of the stomach to the lesser curvature of the body just above the esophagogastric junction, and the patient was diagnosed with moderately differentiated tubular adenocarcinoma(cT4bN3aM0, cStage ⅣA). As esophageal and diaphragmatic invasion was suspected based on CT findings, S-1 plus CDDP was started as preoperative chemotherapy. Although the primary lesion and lymph node metastasis decreased in size, chemotherapy was discontinued after one course due to stenosis symptoms, and total gastrectomy and D2 dissection were performed. Postoperative adjuvant chemotherapy with S-1 was started. However, 6 months after starting the treatment, para-aortic lymph node recurrence was observed, and the treatment strategy was changed to weekly PTX. After 5 courses of weekly PTX, the lymph nodes continued to increase in size, and chemotherapy was discontinued per the patient's request. The patient was followed up with CT and PET-CT; however, no new recurrent lesions were found in other sites for approximately 1 year. Therefore, para-aortic lymph node dissection was performed as the salvage surgery. Pathological findings showed that gastric cancer metastasis was present in 1 swollen lymph node only, as confirmed by PET. At present, 6 years have passed since the first operation, and there has been no recurrence. In general, para-aortic lymph node metastasis is considered to result in poor prognosis in gastric cancer. However, in the absence of other noncurative factors, a good prognosis may be obtained with combined therapeutic modalities.

背景 : 穿刺吸引細胞診にて淡明細胞型腎細胞癌との鑑別が問題となった血管肉腫を経験し, その診断に Giemsa 染色が有用であったので報告する.