池田 美奈

OBJECTIVE: Eosinophilic gastrointestinal disorders (EGIDs) are pathologically diagnosed by manually counting the eosinophils in biopsy tissue under microscopy. However, the skill of the individual examiner is considered to influence the accuracy of the resulting eosinophil count (EC). This study aimed to examine the effects of different examiners and histopathological staining types on the EC results of pathological tissues from patients with EGIDs. METHODS: Infiltrating eosinophils in lesion tissues from 10 eosinophilic esophagitis and 28 eosinophilic gastroenteritis cases were counted by three pathologists and one cytotechnologist. The intra- and inter-observer variabilities in ECs related to hematoxylin-eosin (HE), May-Grünwald Giemsa (MG), and direct fast scarlet (DFS) staining were investigated. The effects of examiner expertise and staining method on ECs were analyzed using a linear mixed effects model. The difference in color value (ΔE) for each staining method was obtained using the Commission International de l'Eclairage luminance-a-b model (L*a*b*). RESULTS: There was no significant intra-observer variability in eosinophil counting. Regarding inter-observer agreement, the examiner with the most EGIDs experience reported higher ECs than the other examiners for all three staining types (P<0.001). ECs were significantly higher with MG and DFS staining than with HE staining, regardless of the examiner (both P<0.001). Additionally, the ΔE values with DFS were higher than those with MG and HE. CONCLUSIONS: DFS staining offered the most selective visualization of eosinophils. ECs may vary depending on both the skill of the examiner and the staining method.

This study aimed to validate the DFS (direct fast scarlet) staining in the diagnosis of EC (eosinophilic colitis). The study included 50 patients with EC and 60 with control colons. Among the 60 control samples, 39 and 21 were collected from the ascending and descending colons, respectively. We compared the median number of eosinophils and frequency of eosinophil degranulation by HE (hematoxylin and eosin) and DFS staining between the EC and control groups. In the right hemi-colon, eosinophil count by HE was useful in distinguishing between EC and control (41.5 vs. 26.0 cells/HPF, p < 0.001), but the ideal cutoff value is 27.5 cells/HPF (high-power field). However, this method is not useful in the left hemi-colon (12.5 vs. 13.0 cells/HPF, p = 0.990). The presence of degranulation by DFS allows us to distinguish between the groups even in the left hemi-colon (58% vs. 5%, p < 0.001). DFS staining also enabled a more accurate determination of degranulation than HE. According to the current standard to diagnose EC (count by HE staining ≥20 cells/HPF), mucosal sampling from left hemi-colon is problematic since the number of eosinophils could not be increased even in EC. Determination of degranulated eosinophils by DFS may potentiate the diagnostic performance even in such conditions.

Ovarian carcinosarcoma is a rare and aggressive tumor with a poor prognosis. We report a case of ovarian carcinosarcoma and also review the literature. In 2000, a 63-year-old woman underwent optimal cytoreductive surgery for ovarian carcinosarcoma( International Federation of Gynaecology and Obstetrics[FIGO]stage III c[pT3cN0M0]). She received adjuvant chemotherapy with paclitaxel and carboplatin(TC). In 2005, a recurrent tumor was noted anterior to the sacrum. The patient had a complete response after 6 cycles of TC chemotherapy; however, a year later, the tumor recurred and was resected. In 2013, the tumor recurred adjacent to the right kidney and was surgically removed after a partial response to 3 cycles of TC chemotherapy. The pathologic findings included epithelial and non-epithelial components with histologic variation and differentiation; specifically, a leiomyosarcoma, cartilaginous tissues with cellular atypia, and a rhabdomyosarcoma were identified in specimens obtained during the first, second, and third surgical procedures, respectively. In keeping with the combination theory of histogenesis, the ovarian carcinosarcoma described herein may have originated from a monoclonal stem cell. The long survival of this patient is attributed to optimal cytoreduction during the primary operation, solitary recurrent tumors that were completely resected, and sensitivity to chemotherapy.