Objective : The treatment effect of neoadjuvant chemotherapy (NAC) is determined by postoperative histology. However, there are no reports describing the cytological prediction of treatment efficacy or use of lymph node cytology. We therefore conducted a cytological study of metastatic lymph nodes to predict the efficacy of NAC.

Study Design : We selected 17 triple-negative cases with malignant findings on preoperative lymph node cytology following surgical resection after NAC between 2018 and 2021.

Results : The pathological response to NAC was grade 0 in 1 case, grade 1 in 8 cases, grade 2 in 2 cases, and pathological complete response (pCR) in 6 cases.

The background findings of lymph node cytology showed necrosis in 7 of 10 patients with grade 1 or 2. The appearance of metastatic cells differed according to the response to NAC. Small clusters (＜20 cells) were seen in 7 of the 8 grade 0 or 1 cases and were more common in cases with a poor response to NAC. Scattered cells were seen in 9 cases of grade 0 to 2 and in 1 case of pCR and were more common in cases with a poor response to NAC. Large clusters (≥150 cells) were found in 9 cases and were more common in cases with a high response to NAC. Cellular atypia of the metastatic cells was not associated with the response to NAC.

Conclusion : Lymph node cytology findings are expected to be useful for predicting the response to NAC and may help in selection of the optimal therapy.

Objective : This study was aimed at evaluating the utility of the membrane filter (MF) method for rapid on-site cytologic evaluation (ROSE) during endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA).

Study Design : The study was conducted using EUS-FNA specimens obtained from 82 cases of pancreatic adenocarcinoma and 36 cases of gastric submucosal tumor. The specimens were divided into two groups based on the preparation method used for ROSE, namely, the squash method (squash group) and the MF method (MF group). We compared the number of specimens prepared, the percentage of specimens with tumor cells, and the number of tumor cells between the squash group and the MF group. In addition, we compared the diagnostic adequacy of the prepared cell-blocks between the two groups.

Results : For both pancreatic adenocarcinoma and gastric submucosal tumors, the percentage of specimens with tumor cells was significantly higher in the MF group than in the squash group, despite the lower number of specimens in the latter. The MF group of specimens contained significantly more tumor cells than the squash group of specimens. Furthermore, the diagnostic adequacy of the prepared cell-blocks was higher in the MF group than in the squash group.

Conclusion : The MF method facilitates the assessment of diagnostically relevant cells for ROSE during EUS-FNA. Furthermore, the cell-blocks prepared from specimens processed by the MF method showed improved diagnostic adequacy.

Background : Myxofibrosarcoma (MFS) is one of the typical myxoid sarcomas that occasionally arises in the limb girdle in elderly people, but diagnosis by cytology is often difficult. We report a case of high-grade MFS with a focus on the cytological findings.

Case : A female patient in her 70 s presented to us with a gradually growing mass in the left ankle for 13 years. She was referred to another hospital and diagnosed by biopsy as having low-grade MFS, and she was followed up. Then there were no signs of metastasis, but the mass grew multiple, increased in size, broke through the skin, and self-destructed. About 6 years after the initial visit, she underwent above-the-knee amputation of the left leg. Imprint cytology of the mass revealed a variety of cells with multinucleated and pleomorphic cells among atypical spindle cells against a background of myxoid matrix, as well as abundant mitotic figures. In addition to numerous branching capillaries, a small number of characteristic curvilinear vessels were also observed. Based on these findings, we diagnosed a high-grade malignant tumor.

Conclusion : Differentiation of MFS in the absence of clear-cut cytologic features is often difficult. It is important to consider the possibility of MFS based on comprehensive diagnostic examinations, including clinical history taking, findings of imaging examinations, findings of detailed morphologic observations, etc.

Background : Body cavity fluid cytology is useful for diagnosing malignant mesothelioma, which can be suspected based on the cytological morphology ; however, reports on the detection of numerous psammoma bodies on cytology are limited. Herein, we report a case of epithelial pleural malignant mesothelioma, in which cytological examination revealed tumor cell clusters with numerous psammoma bodies.

Case : A man in his 60 s presented to us with computed tomographic evidence of pleural thickening 3 years 8 months after he underwent resection for a lung adenocarcinoma. A pleural fluid sample was submitted for cytology, which revealed spherical and papillary cell aggregates with numerous psammoma visualized within the agglomerates. The cells contained dense cytoplasm, and cell-within-cell arrangements with hump-like processes were observed. The tumor cells, which showed little atypia, were markedly multinucleated, with oval-shaped nuclei. The morphological characteristics were consistent with the diagnosis of malignant mesothelioma, except for the appearance of numerous psammoma bodies within the tumor clusters. Examination of cell blocks prepared from the specimens revealed positive results of the center of the psammoma bodies for the Feulgen reaction, and positive immunohistochemistry of the cells for MTAP, LCA, CD68, and αSMA, based on which they were thought to be histiocytes or myofibroblasts. Calcium was deposited around these cells.

Conclusion : This case demonstrated formation of concentric structures by psammoma bodies inflammatory cells within the mesothelioma cell clusters and also calcification within the body cavity.

Background : Salivary gland secretory carcinoma (SSC) is defined by its morphological similarity to mammary secretory carcinoma and the presence of the ETV6-NTRK3 fusion gene, and is, in general, a low-grade salivary gland carcinoma. SSC was newly added to the WHO classification of Head and NeckTumors in 2017.

Case : A female patient in her 80 s was detected 2 years before her visit as having a small mass about 2 cm in size in the mucosa of her right upper lip. Imprint cytology revealed solitary to sheet-like, stacked cell clusters of tumor cells against a background of mucus-like material. The N/C ratio was low and the cytoplasm was foamy to granular, with some cells containing vacuolated and acidophilic cytoplasm. The nuclei were round with slightly fine granular chromatin and distinct nucleoli. May-Giemsa staining showed cells with heterochromatic secretions in the cytoplasm. Histological examination revealed that the tumor was almost completely circumscribed, with slight muscular invasion. The tumor showed a lobulated growth pattern and was composed of cell nests with microcystic structures containing a weakly acidic secretory-like substance. We made the diagnosis of SSC based on the above features and positive immunohistochemical staining of the tumor cells for S-100 protein, mammaglobin and SOX10. Fluorescence in situ hybridization (FISH) showed breaking of the ETV6 gene, but not of the NTRK3 gene.

Conclusion : SSCs show diverse cytological features, and it is important to distinguish these tumors from various other tumors.

Background : Seromucinous borderline tumor (SMBT) is a rare tumor that accounts for 5-7％ of all borderline epithelial malignancies. Although there have been numerous reports on the clinical and histological characteristics of SMBTs, there are very few reports on the cytological features of these tumors. Herein, we report a case of SMBT that was suspected from the results of intraoperative ascitic fluid and tumor imprint cytology.

Case : A 59-year-old woman with a left ovarian tumor and massive ascites underwent laparotomy. Intraoperative ascitic fluid cytology showed many scattered atypical squamous cells and few cells containing vacuoles in the cytoplasm. Additional intraoperative tumor imprint cytology revealed squamous cells and clusters of mildly atypical mucinous cells in a background of abundant mucus. None of the cells showed a sufficient degree of atypia to allow a definitive diagnosis of carcinoma. Based on these cytological findings, we suspected SMBT. Intraoperative histopathological examination of frozen sections showed squamous epithelial tissue, papillary proliferation of mucinous gland epithelium, and neutrophilic infiltration of the stroma. We performed total hysterectomy, bilateral adnexectomy, omentectomy as radical surgery, with peritoneal biopsy. Permanent specimens showed endometriotic tissue within the cyst of the tumor and a variety of Mullerian epithelial tissues, similar to the intraoperative frozen sections. Based on these findings, we made a final diagnosis of SMBT, FIGO stage ⅠC3. The patient is currently under follow-up with no evidence of recurrence at two years after the surgery.

Conclusion : The combination of ascitic fluid cytology and imprint cytology is useful for intraoperative diagnosis of SMBTs.