Intramucosal colorectal carcinoma with lymphovascular invasion: clinicopathological characteristics of nine cases.

AIMS: Recent studies have provided the concept of invasive intramucosal colorectal carcinoma (CRC), and a case of intramucosal CRC with lymphatic invasion has been reported; however, the characteristics of such cases and the risk of lymph node metastasis have never been investigated. Therefore, we aimed to assess the pathological characteristics of intramucosal CRCs with lymphovascular invasion as well as the possibility of lymph node metastasis as an indication for additional surgery. METHODS AND RESULTS: To delineate the histological features of intramucosal CRCs with lymphovascular invasion, we analysed several histological features and compared their incidence among nine such cases, as well as 20 other cases of intramucosal CRCs without lymphovascular invasion. High-grade tumour budding and a pattern of 'eosinophilic cytoplasm and round nuclei with inflammatory reaction (ERI)' were morphological characteristics of intramucosal CRCs with lymphovascular invasion, compared with those without lymphovascular invasion (both P < 0.05). Among the seven lymph node-dissected cases of intramucosal CRCs with lymphovascular invasion, none showed lymph node metastasis. CONCLUSIONS: In intramucosal CRCs with lymphovascular invasion, high-grade tumour budding and the 'ERI' pattern are morphological characteristics that are distinct from those of non-invasive CRC, which is synonymous with high-grade dysplasia. Further studies using a larger number of cases by focusing on the above-mentioned histological pattern are expected to clarify the potential of lymph node metastasis of such cases.

L-type amino acid transporter 1 expression in esophageal carcinogenesis according to WHO and Japanese classifications of intraepithelial neoplasia.

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.

Can EUS-FNA cytology reliably classify gastric submucosal spindle cell tumors?

BACKGROUND: Cytological diagnosis using endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for gastric submucosal spindle cell tumors, such as gastrointestinal stromal tumors (GISTs), leiomyomas, and schwannomas, is challenging because of their similar morphological characteristics. OBJECTIVE AND MATERIALS: To clarify the cytological differential points, we reviewed the EUS-FNA cytology specimens of GISTs (37 cases), leiomyomas (11 cases), and schwannomas (4 cases). METHOD: Twelve cytomorphological features were evaluated: lymphocytes, crushed nuclei, naked spindle nuclei, mast cell, length of the streaming arrangement, cellularity, nuclei at the cluster margin (nuclei located at the periphery of the cell cluster), peripheral feathering (loosely aggregated cells at the margin of a cell cluster tended to taper like feathers), metachromasia, wavy nuclei, fishhook-type nuclei, and anisonucleosis. RESULTS: Among these features, lymphocytes, naked spindle nuclei, length of the streaming arrangement, cellularity, nuclei at the cluster margins, peripheral feathering, and anisonucleosis were statistically significant for differentiation. Based on these findings, we developed an algorithm for cytodiagnosis. The algorithm was taught to four cytologists, and the interobserver agreement and correct diagnosis rates were compared before and after education, which showed a significant improvement. DISCUSSION: The histological types of gastric submucosal spindle cell tumors can be estimated using this algorithm for EUS-FNA cytology. Furthermore, this algorithm can be applied for cytological diagnosis at bedside during rapid on-site evaluation.

Two cases of adenocarcinoma in situ arising in lobular endocervical glandular hyperplasia indicating localization of mucin on the cluster surface as an early cytological finding of malignant transformation.

Lobular endocervical glandular hyperplasia (LEGH) is an endocervical glandular hyperplastic lesion containing pyloric gland-like mucin, and has recently been recognized as a precursor lesion of malignant glandular lesions of the endocervix. The pyloric gland-like mucin contained in LEGH and gastric-type adenocarcinoma is observed as golden-yellowish by Papanicolaou staining. However, to our knowledge, the chronological course of the endocervical cytology of LEGH, eventually resulting in malignancy, has never been demonstrated to date. Here, we report two cases of gastric-type adenocarcinoma in situ (AIS) arising in LEGH, together with an analysis of their cytological course. In both cases, localization of mucin on the surface of glandular cell clusters was observed prior to nuclear atypia in endocervical cytology. In addition, the diagnosis of gastric-type AIS arising in LEGH was confirmed by pathological diagnosis of hysterectomy specimens in both cases. Histologically, all glandular cells of the LEGH without nuclear atypia contained a large amount of PAS-positive mucin. On the other hand, in atypical glandular cells, localization of the mucin on the luminal surface was observed, although mucin was abundant throughout the cytoplasm in some areas. Our cases show the course of acquirement of cytological atypia of LEGH, and indicate the significance of localization of mucin on the surface of glandular cell clusters as an early finding of the malignant transformation of LEGH in endocervical cytology. Our results indicate that the distribution of mucin in glandular cells should be analyzed together with nuclear atypia in the endocervical cytology of suspected cases of LEGH.