Clinicopathological features of in situ follicular neoplasm and relations with follicular lymphoma in Japan.

This study aims to investigate the clinicopathological features of in situ follicular neoplasm (ISFN) in Japan. ISFN is a rare condition formerly considered as an early precursor of follicular lymphoma (FL). This is a first original report of ISFN from Asian country. We reviewed 19 biopsy samples of ISFN. ISFNs were categorized into two groups: (1) ISFN, consisting of ISFN with strong positivity for BCL-2 immunohistochemical staining (IHC), and obvious translocation of BCL-2; and (2) ISFN-like FL, featuring cases without obvious translocation but having morphological features and characteristic IHC findings of ISFN. As control, we adopted obvious FL. For some cases showing coexisting ISFN and FL lesions in the same lymph node, we could conduct further clonality analysis for each lesion. Nine of the 19 cases of ISFN coexisted with FL or had a history of overt B- or T-cell lymphoma including FL. Statistical comparison among ISFN-like FL and FL showed no significant differences in pathological features. Molecular analysis suggested that ISFN lesion and FL lesion in the same lymph node each have a different clonality. ISFN coexists or associates with other overt lymphomas frequently.

The nature of the white opaque substance within colorectal neoplastic epithelium as visualized by magnifying endoscopy with narrow-band imaging.

Background and study aims: We previously reported our discovery of a white opaque substance (WOS) that is opaque to endoscopic light inside the epithelium while using magnifying endoscopy (ME) to examine gastric epithelial neoplasia. Histopathologic analysis revealed that the WOS comprises minute lipid droplets (LDs) accumulated within the neoplastic epithelium. In addition, the WOS was found in colorectal epithelial neoplasia, although it was unclear whether this WOS corresponded to an accumulation of LDs, as in the stomach. Therefore, the aim of the current study was to elucidate whether the WOS observed in colorectal epithelial tumors comprises LDs. Patients and methods: A consecutive series of 40 WOS-positive and 40 WOS-negative colorectal epithelial tumors was analyzed. One biopsy specimen was taken from each neoplasm. Cryostat sections were stained with oil red O for LD, and sections after formalin-fixation for LD were immunostained with anti-adipophilin antibody. Results: The prevalence of LDs stained with oil red O in WOS-positive vs. WOS-negative lesions was 47.5 % (19/40) vs. 5 % (2/40), respectively (P < 0.001). Furthermore, the WOS coincided with the expression of adipophilin; the prevalence of LDs stained by anti-adipophilin antibody in WOS-positive vs. WOS-negative lesions was 100 % (40/40) vs. 62.5 % (25/40), respectively (P < 0.001). Conclusions: This study elucidated for the first time that endoscopically visualized WOS in colorectal epithelial neoplasia may be composed of LDs accumulated in the neoplastic epithelium.

Nature of white opaque substance in gastric epithelial neoplasia as visualized by magnifying endoscopy with narrow-band imaging.

BACKGROUND AND AIMS: Magnifying endoscopy (ME) with narrow-band imaging (NBI) revealed a white opaque substance (WOS) within the superficial part of the gastric neoplasia; however, its nature has remained obscure. A WOS noted within the duodenum was reported to comprise lipid droplets (LD) absorbed by the duodenal epithelium. We attempted to ascertain whether the WOS within gastric neoplasia could also comprise LD and whether the presence of this WOS could be correlated with a specific phenotype. METHODS: Forty-three patients with early gastric epithelial neoplasia underwent ME with NBI. The presence or absence of WOS in the neoplasias was recorded based on the findings of ME with NBI. One biopsy specimen was taken from each of the neoplasias. Cryostat sections underwent oil red O staining for LD. Serial sections were immunostained using the first antibody of CD10, MUC2, CDX2, human gastric mucin, MUC5AC and MUC6. The tissue phenotype was classified as intestinal (I), gastric (G) and gastrointestinal (GI) type based on the results of immunostaining. In total, 49 gastric neoplasias from 43 patients were investigated. RESULTS: Prevalence of LD in WOS-positive versus WOS-negative lesions was 96.2% (25/26) and 4.3% (1/23), respectively (P < 0.001, Fisher's exact test). WOS was present in GI- and I-type lesions, but not in G-type lesions. CONCLUSIONS: WOS may be LD that have been accumulated in the superficial part of the gastric neoplasia of a certain intestinal phenotype.

A multivariate statistical study to obtain effective criteria to detect well-differentiated adenocarcinoma in endometrial cytology.

Consistency in endometrial cytology is relatively poor. This can be partly attributed to generally accepted criteria based on cellular features. The cytological distinction between grade-1 adenocarcinoma and endometrial hyperplasia is more reliant on architectural features than cellular features. We examined statistical criteria based on cytoarchitecture for detecting grade-1 adenocarcinoma in endometrial cytology. Histologically, the study population consisted of 11 cases of grade-1 adenocarcinoma, 6 of atypical endometrial hyperplasia, 16 of endometrial hyperplasia without atypia, and 74 of a normal proliferative endometrium. In each case, all cellclumps were divided into five patterns (tubular; sheet; dilated and/or branched tubular; regular overlapping; atypical). The frequencies of each pattern were submitted to five-variate cluster analysis. The validity and reproducibility of cluster analysis were tested by canonical discriminant analysis and multigroup linear discriminant analysis, respectively. All 107 cases were classified into three groups, A (11), B (36), and C (60), by five-variate cluster analysis. In comparison with this classification and histopathologic diagnosis, group A corresponded to adenocarcinoma, and groups B and C correlated with non-carcinoma. Most cases of atypical endometrial hyperplasia were included in group B. These data suggest that statistical groupings based on cytoarchitecture are useful in the discrimination of grade-1 adenocarcinoma from endometrial hyperplasia and normal tissue.