Solid-pseudopapillary tumor (SPT) is an unusual pancreatic neoplasm that is characterized by a mixture of solid and cystic components and a fibrous capsule. Recently, the tumorigenesis of SPT has been reported to be associated with gene mutations of beta-catenin, which is a molecule participating in the Wnt signaling pathway. Reported herein is the case of a 53-year-old woman with SPT. The tumor, approximately 3 cm in diameter in the pancreas body, had a clear margin and central calcification but had neither a cystic component nor fibrous capsule. Several lines of pathological findings in the surgically resected specimen indicated SPT: (i) pseudopapillary proliferation of eosinophilic polygonal cells with oval nuclei; (ii) positive expression of several marker molecules indicating differentiation into acinar and endocrine cells; and (iii) zymogen granule-like structures in the cytoplasm on electron microscopy. Further, the tumor cells had intense nuclear accumulation of beta-catenin and an activating mutation, (34)Gly(GGA) to Arg(AGA), in exon 3 of the beta-catenin gene, as previously reported in most SPT. These findings suggest that association of the beta-catenin phenotype with development of the rare phenotype of SPT, a non-cystic and unencapsulated tumor, is unlikely.
A 45-year-old woman was first seen by us 2 years after becoming aware of a slightly painful subcutaneous mass in her left vulva. The mass was 7.5 x 3.0 cm in size, well circumscribed, mobile, and rubbery. It was at first clinically considered to be a benign tumor. Microscopically, the resected mass was composed of spindle or polygonal tumor cells which were cellularly or hypocellularly arranged with perivascular accentuation in a mucoid or fibrocollagenous background. Immunohistochemically, myxoid tumor cells were positive for vimentin but not for alpha-smooth muscle actin, CD34, CD31, desmin, or S-100 protein. The tumor was diagnosed as an angiomyofibroblastoma (AMBF), based on the typical findings of histology and immunohistochemistry. There are many histological types of vulvar tumors, and establishing a preoperative diagnosis is difficult in many patients. Rapid intraoperative pathological diagnosis should be performed if possible, considering the possibility of diseases such as AMFB and aggressive angiomyxoma (AAM). When AAM is suspected, the peripheral tissues should also be resected to prevent recurrence.
Thymidine phosphorylase levels are higher in some human cancer tissues than in adjacent normal tissue. However, the ultrastructural localization of thymidine phosphorylase in cancer tissue has been demonstrated only in advanced gastric and colorectal cancer. We investigated the localization of thymidine phosphorylase in breast cancer tissue by immunohistochemistry and its ultrastructural localization by immunoelectron microscopy. Surgically resected specimens from 30 cases of breast cancer were analyzed. Immunohistochemical analysis revealed that cancer cells were positive in 13 cases. However, there were 21 cases that showed thymidine phosphorylase-positive inflammatory cells in cancer tissue. Thymidine phosphorylase-positive staining was detected among both cancer cells and inflammatory cells in 11 cases. Thymidine phosphorylase was diffusely positive in the cytoplasm of cancer cells and specifically positive in mitochondria of neutrophils and specific cytoplasmic granules of macrophages in cancer tissue by immunoelectron microscopy. These findings suggest that thymidine phosphorylase is produced by macrophages and is present in mitochondria of neutrophils and cytoplasmic granules of cancer cells.
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