岡部 麻子

Distal intramural spread refers to microscopic tumor implantation in the intestinal wall, distal to the inferior edge of a macroscopic tumor but rarely beyond 2 cm. We report a case of rectal cancer with preoperatively diagnosed distant intramural spread to approximately 6.5 cm. A 75-year-old woman diagnosed with upper rectal cancer was scheduled to undergo low anterior resection 5 weeks after initial presentation. However, preoperative digital rectal examination and anoscopy under general anesthesia revealed a rectal tumor 4 cm proximal to the anal verge; adenocarcinoma was diagnosed based on frozen section analysis of the rectal tumor. Therefore, abdominoperineal resection was performed, and histopathological examination confirmed a moderately differentiated adenocarcinoma with distal intramural spread of 6.5 cm. The patient died 18 months postoperatively owing to lung metastasis. Although distal intramural spread is rare and can be difficult to detect prior to surgery, repeated rectal examination, with prompt histological examination of suspicious lesions, can ensure earlier diagnosis to achieve better local control by radical surgery including sufficient distal margin.

Intestinal metastases from colorectal cancer typically occur by intraperitoneal spread, whereas those occurring via hematogenous route are exceedingly rare. We report a case of intestinal metastases from sigmoid colon cancer that presented as iliopsoas abscess and ileus. A 78-year-old man who had undergone sigmoidectomy for sigmoid colon cancer 5 years ago was referred to our hospital with recurrent ileus and fever. Abdominal computed tomography showed a left iliopsoas abscess and a mass near the abscess that had ostensibly caused ileus. The patient underwent segmental resection of the jejunum including the mass. Histopathological examination of the resected specimen revealed moderately differentiated adenocarcinoma proliferating mainly in the submucosal and muscular layers, which was pathologically identical to the colon cancer resected 5 years ago. He died 18 months after the surgery because of liver metastases. This case report highlights the delayed occurrence of colorectal metastases at unusual sites, such as the small bowel, more than 5 years after the resection of the primary cancer. Intestinal metastases should be considered in patients with a history of colon cancer, particularly in those with recurrent ileus or abdominal abscess with no obvious cause.

Glioneuronal tumor (GNT) is a rare central nervous system neoplasm composed of glial and neuronal components. Making the specific diagnosis of GNT can be challenging due to histopathological and genetical similarities among some GNTs and low-grade gliomas. We report a case of GNT with rosette-forming glioneuronal tumor, dysembryoplastic neuroepithelial tumor, and pilocytic astrocytoma-like morphology harboring FGFR1 mutation. A 16-year-old female presented with absence seizures. Magnetic resonance imaging revealed a right temporal lobe mass with multinodular enhancement by gadolinium administration. The tumor was mostly composed of oligodendrocyte-like cells (OLCs) with variable perinuclear haloes. Abundant Rosenthal fibers and eosinophilic granular bodies were identified. Neither mitotic figures nor areas of necrosis were seen. Focal neurocytic rosette features, involving ring-like arrays of OLCs around eosinophilic cores, were observed. Direct sequencing showed a missense mutation in FGFR1 K656E, whereas FGFR1 N546K, PIK3CA, and BRAF V600E were intact. KIAA1549-BRAF fusion was not detected by fluorescence in situ hybridization analysis.