Objective : The purpose of this study was to evaluate the impact of the coronavirus disease 2019 (COVID-19) pandemic on various aspects of cytology practice in Japan.

Study Design : Based on the annual reports of accredited facilities of the Japanese Society for Clinical Cytology, including hospital-based cytopathology laboratories, cancer screening facilities, and clinical laboratories, we evaluated the impact of the COVID-19 pandemic on the cytology services by comparing the number of cytology specimens, participants in conferences and workshops, and other factors in 2019 and 2020.

Results : In terms of the type of facilities, there was a noticeable decrease in the number of specimens from cancer screening facilities. In regard to the specimen source, the number of sputum, respiratory, breast, thyroid, and uterine cervical were significantly decreased. In terms of training of cytopathologists, the total number of participants in meetings decreased, but in a region, it was higher in 2020 than in 2019.

Conclusion : The results of this study demonstrated a significant decrease in the number of cytology specimens received for testing during the COVID-19 pandemic. To avoid delayed diagnosis of malignancy and the associated mortality, healthcare professionals should encourage the public to undergo cancer screenings.

Background : Actinomycosis is a chronic suppurative granulomatous infection caused mainly by the anaerobic gram-positive bacillus Actinomyces israelli. It has been suggested to be associated with the long-term use of intrauterine devices (IUD) in female patients. We report a case of uterine actinomycosis diagnosed by smear cytology, even though uterine cancer was suspected on imaging, which was confirmed by confirmation of the presence of Actinomyces species in a uterine lavage specimen.

Case : A female patient in her 50 s visited a previous physician with the chief complaint of lower abdominal pain, and was referred to our hospital for further examination and treatment, because MRI revealed soft tissue shadows in the uterus with unclear borders extending into the rectum, which led to the suspicion of uterine cancer with rectal invasion. Examination of the patient revealed an IUD inserted 18 years earlier, which was removed. Cervical, endometrial, and IUD touch smear cytology revealed no malignant findings. Papanicolaou staining revealed a gray-blue bacterial mass in an inflammatory background. The patient was diagnosed as having pelvic infection caused by actinomycosis, and was treated with antibiotics for 6 months. Microbiologic analysis of an intrauterine lavage specimen confirmed the presence of Actinomyces mediterranea.

Conclusion : In patients with long-term IUD implantation, cytological diagnosis can lead to early diagnosis, even when imaging studies show soft tissue shadows in the pelvis. In this case, microbiologic analysis of an intrauterine lavage specimen confirmed Actinomyces mediterranea as the causative bacterium.

Background : We report a case of mesothelioma in which cytology revealed numerous signet ring cells, and it was a challenge to differentiate the case from adenocarcinoma. In our cytological study reported herein, we compared the cells for which differentiation was a problem that were difficult to identify accurately. We also discuss the relevant literature and gene mutations in the signet ring cells.

Case : The patient was a 65-year-old Japanese male with a history of asbestos exposure. PET-CT was suggestive of pleural mesothelioma and pleural fluid cytology was performed. Many of the cells showed vacuolated cytoplasm and could not be clearly differentiated from adenocarcinoma cells. However, mesothelioma was suspected based on the mixture of cells showing combination of nuclear findings, microvilli findings, and metachromasia. Immunohistochemical staining was performed on the cell block prepared at the same time, and based on the findings, we made a final diagnosis of mesothelioma.

Conclusion : There is a morphological difference are morphological differences between the signet ring cells found in adenocarcinoma and those found in mesothelioma. We suggest that based on the findings in the present case and our literature review, signet ring cells showing metachromasia are characteristic of mesothelioma. Comparison of gene mutations with the surrounding mesothelioma cells in the present case indicated that the signet ring cells also undergo gene mutations similar to those occurring in the mesothelioma cells.

Background : Fecaluria occurs as a result of fistula formation between the intestinal tract and the urinary tract. Fecaluria and pneumaturia are frequent findings in cases of enterovesical fistulas. To date, we have encountered three cases of enterovesical fistula in which fecal material was detected on urinary cytology.

Cases : Case 1 was a man in his 60 s who underwent further medical examination for pneumaturia and hematuria. Urinary cytology revealed atypical cells and fecal materials. The patient was eventually diagnosed as having an enterovesical fistula associated with sigmoid colon cancer.

Case 2 was a man in his 60 s who consulted a doctor for fever. Fecal material was detected in the urinary sediment prepared for urinalysis before he was referred to our hospital. At our hospital also, urinary cytology revealed fecal materials, and the patient was diagnosed as having an enterovesical fistula associated with rectal cancer.

Case 3 was a man in his 50 s who consulted a doctor for fever and pain during urination. The patient was referred to our hospital with suspected enterovesical fistula. He was eventually diagnosed as having an enterovesical fistula associated with sigmoid diverticulitis. Urinary cytology revealed fecal materials. Surgical resection was performed in all three cases, and adjuvant chemotherapy was administered for Case 1 and Case 2.

Conclusion : If a urine specimen shows fecal materials, the possibility of enterovesical fistula should be considered. Urine testing is simple and non-invasive. We believe that urinary cytology will help with the diagnosis and should be performed aggressively in suspected cases.

We report a case of thyroid oxyphilic cell follicular carcinoma (oncocytic carcinoma) in a 33-year-old Japanese man. The thyroid tumor measuring 20 mm in diameter was examined by fine-needle aspiration (FNA) cytology, and a diagnosis of benign oncocytic tumor was made. Five years later, at the time of surgery, the tumor had grown to 40 mm in diameter.

FNA cytology at the time of surgery showed oncocytes, in greater numbers and heterogeneity than in the previous examination. Histological examination of the resected tumor revealed the diagnosis of oncocytic carcinoma.

The cytological findings showed temporal histopathological changes of oncocytic carcinoma, including decreased follicular structures and increased cellular atypia.