No abstract

Meningiomas show a diverse histopathologic appearance, often referred to as metaplastic changes; however, adenocarcinoma-like metaplasia is an extremely rare condition. Here, we present a novel case. A dura-based bulky mass located in the right frontotemporal region was identified radiologically in an 83-year-old woman. The tumor, yellow to ash-gray in color, was subtotally removed. Histopathological examination revealed robust adenocarcinoma-like structures within a conventional meningothelial neoplasm. Meningioma elements showed a WHO grade I to III histology. Morphological and immunophenotypic transition between meningothelial and columnar epithelial cells was confirmed on detailed observation. It was of note that the adenocarcinomatous components shared an immunophenotype with intestinal epithelium, expressing CDX2, MUC2 and cytokeratin 20. The present case could be differentiated from secretory meningioma based on distinct cellular atypia, lack of intracytoplasmic lumina and pseudosammoma bodies, and the intact status of the KLF4 gene. In addition, the morphological and immunophenotypic transition excluded the possibility of metastatic carcinoma within meningioma. This is the first reported case of meningioma with adenocarcinoma-like metaplasia harboring an intestinal immunophenotype.

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A 61-year-old man who had undergone surgery for renal cell carcinoma 11 years ago was found to be positive for fecal occult blood. CT was performed and tumors were found in the body and tail of the pancreas and liver flexure of the colon. Total colonoscopy showed that the colorectal tumor was a submucosal tumor-like protuberant hypervascular lesion, but a biopsy did not provide a definitive diagnosis. Based on the clinical course, recurrence of renal cell carcinoma with pancreas and colon metastasis was diagnosed. Distal pancreatectomy and partial resection of the transverse colectomy were performed. After surgery, a pancreatic fistula was found, followed by focal peritonitis, omental necrosis, and an intraabdominal abscess. The patient improved with conservative treatment including CT-guided drainage and was discharged from hospital on the 88th postoperative day. Colon metastasis from renal cell carcinoma is extremely rare and metastasis to multiple organs is often observed. In addition to surgical resection, drug therapy with immune checkpoint inhibitors is effective in some cases, but further investigation is needed. In surgical excision of a colorectal tumor in the transverse colon, the pancreatic transection and colonic anastomosis are close to each other, and this may contribute to the relationship between pancreatic fistula and infection.

A 74-year-old woman was referred to our hospital for the evaluation of slightly elevated tumor marker levels. Computed tomography revealed a well-demarcated tumor, approximately 15 mm in diameter, in the pancreatic tail. Endoscopic ultrasound-guided fine-needle aspiration findings suggested poorly differentiated cancer. The tumor was surgically resected, but postoperative pathologic confirmation was not possible. After one year without treatment and no recurrence, an evaluation by a specialized facility was requested for a definitive diagnosis. Adenomatoid tumor was deemed most likely based on the histopathology and immunostaining findings; however, a definitive diagnosis was difficult because of atypical findings. The patient was recurrence-free for 36 months at the last follow-up.