Mucinous urothelial carcinoma (UC) is a rare variant and only 18 cases of mucinous UC have been reported. In this article, we report a case of mucinous UC focusing on both cytological and histological findings. A 92‐year‐old female was referred to our hospital because of gross hematuria. Clinical computed tomography scan showed 2.2‐cm papillary lesion in the lower part of the left ureter. Urine cytology was performed, and cytopathological findings showed that there were a few atypical cells with pale to clear cytoplasm, and a low amount of mucin in the background was identified by periodic acid‐schiff (PAS) and alcian blue (AB) staining. Laparoscopic radical nephrectomy of left renal pelvis and ureter was performed. The gross examination revealed that a white‐gray, papillary‐sessile tumor was found in the lower part of the left ureter. Histologically, conventional high grade UC cells were seen in some areas, and tumor cells in other areas showed abundant clear cytoplasm with extracellular and intracytoplasmic mucin. Immunohistochemical analysis revealed that tumor cells were positive for CK7, CK20, p63, GATA3, MUC1, MUC2, and MUC5AC and negative for MUC6 and CDX2. Histopathological diagnosis was mucinous UC with clear cell component, and the pathological stage was pT1N0M0. The patient has remained well and disease‐free for 3 months after the operation. Familiarity and recognizing the characteristic pathological findings of mucinous UC are important because it represents a malignant neoplasm.

BackgroundUrothelial carcinoma (UC) is a common type of human cancer and, although urine cytology is a useful method for identifying high‐grade UC (HGUC), its ability to diagnose low‐grade UC (LGUC) is limited. The authors previously reported that annexin A10 (ANXA10) expression was strongly linked to both papillary and early stage LGUC and was inversely correlated with p53 expression in upper tract UC (UTUC) and bladder UC. However, it remains largely unknown whether ANXA10 is useful as a diagnostic marker for urine cytology.MethodsIn this study, the authors used 104 biopsy and 314 urine cytology samples to investigate the efficacy of ANXA10 and p53 expression by immunohistochemistry and immunocytochemistry.ResultsIn immunohistochemistry analysis, expression levels of ANXA10 and p53 were either weak or absent in noncancerous tissues, whereas ANXA10 overexpression was observed patients with LGUC, and strong expression of p53 was identified in patients with HGUC. In immunocytochemistry analysis, sensitivity was not good for the detection of UC, especially UTUC, by cytology alone, but it was improved by combining cytology with ANXA10 and p53 to detect both bladder UC and UTUC. Receiver operating characteristic curve analysis also confirmed the diagnostic superiority of cytology combining ANXA10 and p53 for the detection of all UCs, including both HGUC and LGUC (area under the curve, 0.84).ConclusionsTo the authors’ knowledge, this is the first report that the combination of ANXA10 and p53 has potential application as a diagnostic immunomarker for improving the diagnostic accuracy of urine cytology.

Bilateral synchronous paratesticular leiomyoma (BSPL) is a rare tumor that originates from smooth muscle cells in the paratesticular region. Four BSPL cases have been reported sporadically, starting with the 1991 report by Aus and Boiesen. Herein, we report the case of a 60-year-old male with a bilateral scrotal mass with a maximum size of 7.5 cm. Histological examination revealed oval to spindle-shaped tumor cells with a fascicular growth pattern. Immunohistochemically, the tumor cells were positive for α-smooth muscle actin. The pathological diagnosis was a leiomyoma. Based on the simultaneous bilateral nature of the disease, BSPL was diagnosed. In conclusion, we encountered a rare case of BSPL, and our report may contribute to the understanding of this disease.