There are various mechanisms underlying the resistance of EGFR-mutant lung adenocarcinoma to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs). We herein report a case of ...pulmonary adenocarcinoma with EGFR mutation (exon 19 deletion and T790M) that acquired resistance to osimertinib treatment because of transformation into small-cell lung carcinoma (SCLC). A 67-year-old ex-smoking woman was diagnosed with left upper lobe adenocarcinoma of clinical stage IIIA (cT2bN2M0). She was treated with chemoradiotherapy (cisplatin and vinorelbine plus radiation), gefitinib, cisplatin, and pemetrexed followed by pemetrexed maintenance therapy and erlotinib. Since a sample extracted from the metastatic lung tumor taken obtained via a transbronchial lung biopsy was found to be positive for the T790M mutation at the time of disease progression during erlotinib treatment, she received osimertinib treatment for 15 months until progressive disease. She developed resistance to osimertinib due to the histologic transformation to SCLC. Although the standard chemotherapy of carboplatin and etoposide for SCLC was administered, she died due to metastatic liver failure.
We report a case of a 78-year-old woman with neutrophilia without eosinophilia who was pathologically diagnosed with eosinophilic myocarditis by myocardial biopsy. The biopsy specimen showed ...infiltrating granulocytes with hypersegmentation, mimicking neutrophils; however, they were confirmed to be eosinophils by Giemsa staining.
Metastatic diseases rarely develop in the colorectum, and diagnosing colorectal metastasis by biopsy without history of a malignant tumor or clinical information of a primary tumor is challenging. A ...65-year-old woman with a 6-month history of constipation and diarrhea was admitted to our hospital and diagnosed with rectosigmoid colonic micropapillary carcinoma. Low anterior resection was performed after neoadjuvant chemotherapy. Because the lipoleiomyoma in the uterus obstructed the operator’s vision, total hysterectomy and bilateral salpingo-oophorectomy were performed. Examination of the colon and adnexa, together with immunohistochemical studies, revealed that the colonic tumor was actually serous carcinoma that had metastasized from the left fimbria of the fallopian tube. Retrospective immunohistochemical examination of the colon biopsy specimen suggested carcinoma with a Müllerian immunophenotype. When a colon biopsy reveals carcinoma with an invasive micropapillary pattern without a component of conventional tubular adenocarcinoma, immunohistochemical examination should be performed to rule out the possibility of metastasis.
A 51‐year‐old woman visited our hospital with the chief complaint of tarry stools. Contrast‐enhanced abdominal computed tomography revealed leakage of contrast medium into the lumen of the small ...intestine. Subsequently, a double‐balloon endoscopy was performed, which revealed a submucosal mass‐like lesion in the jejunum. Although hemostasis was attempted with clips, complete hemostasis was difficult to achieve, and angiographic embolization was performed. Nevertheless, the anemia progressed, and a small bowel resection was performed. Histopathological examination led to a diagnosis of a ruptured submucosal aneurysm of the small intestine. Endoscopic hemostasis is often difficult to achieve for submucosal aneurysms in the intestine. The submucosal tumor‐like finding observed on endoscopy in submucosal aneurysms is termed an “SMT‐like sign” and is considered an important finding to diagnose aneurysms.
Carcinosarcomas with elements of cholangiocarcinoma and sarcoma are rare and have a poor prognosis. The spreading pattern and radiological findings of these lesions remain unclear. A 74-year-old man ...presented with a high γ-glutamyl transferase level. Magnetic resonance imaging revealed dilation of the right intrahepatic and common bile ducts, consistent with an intraductal papillary neoplasm of the bile duct (IPNB), and diffusion-weighted imaging (DWI) indicated an area of high signal intensity in the intrahepatic bile duct. Bile duct biopsy yielded a small amount of atypical spindle cells, and the patient underwent a right hepatectomy. Microscopically, the tumor contained cholangiocarcinoma and sarcomatous components, including osteosarcoma and leiomyosarcoma, leading to a diagnosis of intrahepatic carcinosarcoma. The tumor spread primarily through the intrahepatic bile duct. An accurate radiological diagnosis of carcinosarcoma was challenging, given the apparent similarities with IPNB. The findings from DWI and pathology of a bile duct biopsy may assist with preoperative diagnosis.
L‐type amino acid transporter 1 (LAT1) has an essential role in cell proliferation especially in neoplasms. Although immunohistochemical expression of LAT1 has been investigated in invasive ...esophageal carcinoma, its expression in intraepithelial neoplasia (IEN) has not been reported. Further, classification of esophageal IEN is currently different between the World Health Organization (WHO) and Japanese criteria. Therefore, in this study, immunohistochemical expressions of LAT1 along with Ki‐67 were analyzed in 66 esophageal samples of endoscopic submucosal dissection. Extension of cells positive for either marker within the epithelium, along with LAT1 intensity at the base of the epithelium, was evaluated. The results among early IENs, progressed IENs, and invasive carcinoma based on both WHO and Japanese criteria were compared. It was demonstrated that Ki‐67+ cells extended toward the superficial layer in IENs, which was more pronounced in progressed compared with early IENs based on both WHO and Japanese criteria. Although similar results were obtained for LAT1+ cells, LAT1+ cell extended more in invasive carcinoma than in progressed IENs according to the WHO criteria. Further, LAT1 intensity was different between early and progressed IENs based on the Japanese criteria alone. Thus, use of LAT1 immunohistochemistry and Japanese classification may be more meaningful to characterize esophageal carcinogenesis.
Benign neural tumors or tumor-like lesions are rarely detected in the gastrointestinal tract. In this article, we present the case of a neural lesion of the sigmoid colon, which was incidentally ...detected in a 68-year-old man treated with laparoscopic low anterior resection for an advanced carcinoma of the rectosigmoid junction. Within the resected specimen, a submucosal tumor-like protruding lesion was found in the sigmoid colon. Histologically, the growth was composed of mucosal neurofibromatous and submucosal ganglioneuromatous lesions, between which there was transition. Immunohistochemical analysis revealed a rupture of the perineurium in the area of transition, along with a proliferation of Schwann cells and supporting cells extending into the deep mucosa. This transition indicated that the mucosal and submucosal lesions comprised a single lesion, and that a diagnosis of neurofibroma or ganglioneuroma would be inadequate in this case. Because we could not classify it as an established single entity, we diagnosed the mass as an unclassifiable colonic neurogenic lesion. In summary, we report the case of an extremely rare occurrence of an unclassifiable colonic neurogenic lesion comprising an admixture of transitioning mucosal neurofibromatous and submucosal ganglioneuromatous lesions.
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