Tatsuya Aso

Meningiomas are the most common primary brain tumors worldwide and are classified into 15 subtypes in the 5th edition of the WHO classification. Myxoid meningioma, characterized by the presence of a mucinous matrix within the tumor, is a rare metaplastic meningioma subtype classified as WHO grade 1. Chordoid meningiomas similarly contain a mucinous matrix, but are WHO grade 2. Accurate distinction between these subtypes is essential for determining appropriate treatment and predicting prognosis. Herein, we present a case of myxoid meningioma requiring differential diagnosis from chordoid meningioma. A man in his 60s presented with falls, depression, and urinary incontinence. Imaging revealed a tumor 6 cm in diameter in the right frontal region. Tumor resection with rapid intraoperative diagnosis was performed. Cytology revealed epithelioid cells with oval nuclei, intranuclear cytoplasmic inclusions, and mucinous matrix. Squash cytology confirmed tumor cell clusters with a vascular network. Histological examination revealed tumor cells forming cord‐like structures within an Alcian blue‐positive, Periodic acid–Schiff‐negative mucinous matrix, along with an abundant vascular architecture. Myxoid and chordoid meningiomas share many cytological similarities, and mucin staining patterns are diagnostically unclear. However, the latter tend to show lymphocytic and plasma cell infiltration. This case lacked such infiltration, and the vascular stroma aided differentiation. For rapid intraoperative diagnosis, a combination of frozen sections and cytology, less susceptible to freezing artifacts, is considered beneficial for accurate diagnosis. In meningiomas with a mucinous matrix, careful evaluation of cellular appearance and tumor stroma findings is essential for distinguishing between subtypes with different WHO grades.

Background: Urachal carcinoma (URC) is a rare tumor of the urinary bladder, of which the histology usually resembles that of colorectal adenocarcinoma. Achievement of cure in patients with metastatic URC is difficult, and the survival rate of these patients has remained unsatisfactory despite various efforts.Case: A 74‐year‐old female patient presented to us complaining of gross hematuria. Abdominal and thoracic computed tomography revealed a mass in the dome of the bladder with a single lung nodule. The two tumors, which were resected by partial cystectomy and video‐assisted thoracic surgery, respectively, were diagnosed by postoperative histopathology as adenocarcinomas. Subsequent to the surgeries, bilateral ovarian metastases and another lung metastasis, which appeared metachronously, were also resected. The repeated cytoreductive surgery combined with administration of S‐1 plus cisplatin chemotherapy at each instance of disease progression eventually yielded a durable progression‐free survival; even at 5 years after the initial therapy, the patient remained asymptomatic with no limitation of activities despite the failure to achieve “cure”.Conclusion: Not only some degree of sensitivity of the tumor to chemotherapy, but also the repeated cytoreductive surgeries might allow prolonged survival with a good quality of life in elderly patients with metastatic URC, even in the absence of cure and failure of genetic testing to suggest any potentially effective second‐line drugs. To improve the survival of patients with metastatic URC, complementary therapy suggested by the results of genomic profiling may be necessary along with other multimodality therapy, including sequential metastasectomy and chemotherapy.

BACKGROUND: Endoscopic ultrasound-guided tissue acquisition (EUS-TA) is essential technique for sampling solid pancreatic lesions. However, the optimal needle type for achieving high histological diagnostic capability remains unclear. This study compares the histological diagnostic capabilities of the 19G FNA needle and the 22G FNB needle for solid pancreatic lesions. METHODS: This single-center, retrospective study was conducted in patients who underwent EUS-TA for solid pancreatic lesions. Patients were allocated to either Group A, utilizing the 19G FNA needle, or Group B, utilizing the 22G FNB needle. The primary outcome was the diagnostic accuracy based on histology alone. RESULTS: 143 patients were analyzed, with 61 in Group A and 82 in Group B. Diagnostic accuracy was significantly higher in Group B for both histology alone (85.4% vs. 68.9%, p=0.02) and overall diagnostic accuracy (85.4% vs. 73.8%, p=0.02). Logistic regression analysis revealed that lesion size ≥25 mm was an independent factor contributing to higher diagnostic accuracy (OR 3.32, 95% CI 1.28-8.64, p=0.01). Subgroup analysis showed that diagnostic accuracy for 15–25 mm lesions was significantly higher in Group B (90.0% vs. 63.2%, p=0.02). Additionally, trans-gastric punctures had higher accuracy in Group B (94.7% vs. 73.5%, p=0.01). CONCLUSIONS: Our study showed the overall superiority of the 22G FNB needle for EUS-TA of solid pancreatic lesions. However, 19G FNA needle remains a valuable option under specific conditions.

Background: The recent improvement of peroral cholangioscopy (POCS) maneuverability has enabled the precise, targeted biopsy of bile duct lesions under direct cholangioscopic vision. However, as only small-cup biopsy forceps can pass through the scope channel, the resulting small sample size may limit the pathological diagnosis of biopsy specimens. This study compared the diagnostic abilities of POCS-guided biopsy and conventional fluoroscopy-guided biopsy for bile duct cancer. Method: This multicenter, retrospective cohort study included patients exhibiting bile duct stricture with suspected cholangiocarcinoma in whom POCS-guided and fluoroscopy-guided biopsies were performed in the same session. The primary endpoint was the diagnostic sensitivity for malignancy. The size and quality of the biopsy specimens were also compared. Result: A total of 59 patients were enrolled. The sensitivity of POCS-guided biopsy was similar to that of fluoroscopy-guided biopsy (54.0% and 64.0%, respectively). However, when the modalities were combined, the sensitivity increased to 80.0%. The mean specimen size from POCS-guided biopsy was significantly smaller than that from fluoroscopy-guided biopsy. The specimen quality using fluoroscopy-guided biopsy was also better than that using POCS-guided biopsy. Conclusions: The diagnostic sensitivity of POCS-guided biopsy is still insufficient, mainly because of the limited specimen quantity and quality. Therefore, conventional fluoroscopy-guided biopsy would be helpful to improve diagnostic sensitivity.