Mutsuko Omatsu

Transition from low-grade endometrial stromal sarcoma to high-grade endometrial stromal sarcoma.

We report on a case of a primary low-grade endometrial stromal sarcoma (ESS) that progressed to a secondary high-grade ESS. In the secondary tumor, the immunohistochemical profile and focal tumor cell proliferation pattern suggested that this tumor was not truly undifferentiated, but possessed features of endometrial stroma. Low-grade ESS of our patients primary tumor showed p53 protein overexpression, which is unusual in low-grade ESS, and her secondary high-grade ESS showed more prominent p53 immunoreactivity. This indicates that low-grade ESS that shows p53 immunoreactivity might progress to high-grade ESS, and it is considered that such cases of low-grade ESS should pay attention to the prognosis. Immunoreactivity for epidermal growth factor receptor was observed in both tumors, suggesting a relationship between the primary and secondary tumors in our case. Further study requires more immunohistochemical data for cases in which low-grade ESS transitions to high-grade ESS; in particular, data on epidermal growth factor receptor expression are necessary to define new therapeutic strategies for ESS.

Intraductal oncocytic papillary carcinoma of the pancreas showing numerous hyaline globules in the lumen

Two cases of intraductal oncocytic papillary carcinoma (IOPC) treated surgically were analyzed on light microscopy and immunohistochemistry: that of a 61‐year‐old man and that of a 55‐year‐old man. There were no clinical symptoms in either case. Pancreatic abnormalities were discovered incidentally on CT. Various clinical examinations were carried out, and the preoperative diagnosis was intraductal papillary mucinous carcinoma (IPMC) in both cases. Surgery was performed. Macroscopic observation of tissue cross‐sections indicated multilocular cystic mass containing polypoid lesions encapsulated by the dilated pancreatic duct. Histologically, the cyst walls were lined by columnar epithelial cells with complex papillary projections associated with oxyphilic cytoplasm, and they were strongly immunoreactive with anti‐mitochondrial antibody in the cytoplasm. Electron microscopy showed numerous mitochondria in the cytoplasm. IOPC was diagnosed. Interestingly, amorphous hyaline globules were produced from the oxyphilic cells, which exhibited a bud‐like appearance. The hyaline globules were not positive for mucin staining. No case of IPMC with hyaline globules has been reported to date. The production of hyaline globules may be related to oncocytic differentiation. It is suggested that hyaline globules should be regarded as a characteristic of IOPC.

Expression of PTEN and its pseudogene PTENP1, and promoter methylation of PTEN in non-tumourous thymus and thymic tumours

Aims Mutation or promoter methylation of the phosphatase tensin homologue deleted on chromosome 10 tumour suppressor gene (PTEN) promotes some cancers. Moreover, PTENP1 (PTEN pseudogene) transcript regulates PTEN expression and is thought to be associated with tumourigenesis in some cancers. Here, we investigated PTEN expression in thymic epithelium and thymic epithelial tumours. Methods Immunohistochemical analysis of PTEN was performed on two non-tumourous thymus (NT) samples, 33 thymomas (three type A, eight type AB, 11 type B1, six type B2, and five type B3), and four thymic carcinomas (TCs). In 16 cases (two NT, three A, five B1, two B2, one B3 and three TC), analyses of mutations, promoter methylation and comparisons of PTEN mRNA and PTENP1 transcripts were undertaken using PCR-direct sequencing, methylation-specific PCR, and reverse-transcription real-time PCR after target cell collection with laser microdissection. Results PTEN protein was not immunohistochemically detected in NT epithelium or types B1 or B2 thymoma cells, but was expressed in type A thymoma and carcinoma cells. Neither PTEN mutations nor promoter methylation were detected in any samples. Statistical analysis revealed that PTEN mRNA expression was highest in NT epithelium and lowest in type A thymoma cells. PTENP1 transcript expression did not significantly differ among NT, thymoma and TC samples. Conclusions We speculated that NT epithelium and types B1/B2 thymoma cells have a mechanism of PTEN translation repression and/or acceleration of protein degradation, whereas type A thymoma cells exhibit transcriptional repression of PTEN mRNA and accelerated translation and/or protein accumulation.

The role of microvessel density, lymph node metastasis, and tumor size as prognostic factors of distant metastasis in colorectal cancer

Angiogenesis is essential for tumor growth and metastasis. CD105 is reportedly a specific marker for tumor angiogenesis. It has been demonstrated that monoclonal antibodies to CD105 have high affinity for activated endothelial cells. A relationship between metastasis and microvessel density (MVD), as an indicator of neovascularization, has been identified in patients with colorectal cancer as shown by the presence of monoclonal antibodies to CD105. However, data on potentially confounding factors such as lymphatic and vascular infiltration and tumor size are lacking. We further investigated the relationship between MVD and distant metastasis, along with potentially confounding clinicopathological factors, to more precisely characterize this relationship. In this retrospective study, we analyzed colorectal cancer specimens surgically or endoscopically resected from January to September 2009. We defined MVD as the number of microvessels stained by monoclonal antibodies to CD105 per ×400 field. Selected clinicopathological factors were analyzed and stepwise multivariate logistic regression was performed to identify independent risk factors for distant metastasis. We analyzed 129 lesions. The median follow-up time was 34 months (range, 6-85 months) in patients with distant metastasis and 61 months (range, 60-86 months) in those without distant metastasis. At the time of resection or during subsequent follow-up, 32 patients had distant metastases. The MVD was significantly greater in patients with than without distant metastases (mean ± standard deviation: 10.4±4.9 vs. 7.6±3.3, P=0.008; Welchs t-test). Stepwise multivariate logistic regression indicated that MVD, regional lymph node metastasis, and tumor size were independent risk factors for distant metastases. Combining assessment of monoclonal antibodies to CD105-positive MVD with assessment of regional lymph node metastasis and tumor size may help to identify patients who need more intensive surveillance after surgery for colorectal cancer.

Difference in distribution profiles between CD163+ tumor-associated macrophages and S100+ dendritic cells in thymic epithelial tumors

BackgroundIn a number of human malignancies, tumor-associated macrophages (TAMs) are closely involved in tumor progression. On the other hand, dendritic cells (DCs) that infiltrate tumor tissues are involved in tumor suppression. However, there have been very few reports on the distribution profiles of TAMs and DCs in thymic epithelial tumors. We examined the difference in the distribution profiles between TAMs and DCs in thymoma and thymic carcinoma.MethodsWe examined 69 samples of surgically resected thymic epithelial tumors, namely, 16 thymic carcinomas and 53 thymomas, in which we immunohistochemically evaluated the presence of TAMs using CD68 and CD163 as markers and DCs using S100 as the marker in tumor tissue samples in comparison with normal thymic tissues.ResultsThe percentage of samples with a large number of CD68+ TAMs was not significantly different between thymic carcinoma and thymoma (7/16 versus 16/53, p = 0.904). However, the percentage of sample with a large number of CD163+ TAMs was significantly higher in thymic carcinoma than in thymoma (15/16 versus 34/53, p = 0.024). In contrast, the percentage of samples with a large number of S100+ DCs was significantly lower in thymic carcinoma than in thymoma (2/16 versus 23/53, p = 0.021).ConclusionsTo the best of our knowledge, we are the first to show a high percentage of CD163+ TAMs and a low percentage of S100+ DCs in thymic carcinoma samples, and our findings may provide an idea for future targeted therapeutic strategies for thymic carcinoma using antibodies that inhibit monocyte differentiation to TAMs, thereby skewing TAMs differentiation toward DCs.Virtual SlidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_215

Mixed mucin‐producing and squamous differentiated tumor of the uterine cervix: A report of a case as adenosquamous carcinoma in situ

We report a non‐invasive mixed mucin‐producing and squamous differentiated tumor of the uterine cervix. This tumor was composed of two cell types: mucin‐producing cells and non‐mucin‐producing cells. These cells were intimately mixed with each other, and showed intraepithelial spreading. The mucin‐producing cells showed signet‐ring or columnar shapes, and were localized to the lower‐to‐upper epithelial layer. The non‐mucin‐producing cells had eosinophilic cytoplasms with a monotonous appearance through the epithelium. Mitosis was sometimes observed in both cell types. Immunohistochemically, both cell types were positive for p16INK4A. The non‐mucin‐producing cells were positive for p63 and 34βE12, suggesting squamous differentiation. Although most mucin‐producing cells were p63‐, a few of them were p63+ and many 34βE12 immunoreactive cells were found in the mucin‐producing cells. This tumor was adenosquamous carcinoma in situ.

High-grade endometrial stromal sarcoma with smooth muscle and skeletal muscle differentiation: Report of a case with cytomorphologic and immunocytologic analysis

We report a case of high‐grade endometrial stromal sarcoma with cytological and immunocytochemical findings. Cytologically, major tumor cells showed round‐to‐short spindle shapes with round‐ to oval‐shaped nuclei and moderately abundant delicate cytoplasm. Tumor cells with tapered shapes and eccentric nuclei were also observed. A few spindle cells having enlarged cigar‐shaped nuclei with conspicuous nucleoli and delicate wispy cytoplasm, which resembled leiomyosarcoma, were intermingled. One rhabdomyoblast cell with both α‐sarcomeric muscle actin and myoglobin was also observed. Most of the tumor cells, including the leiomyosarcomatous spindle cells, were positive for CD10, and negative for desmin and h‐caldesmon. Accordingly, when relatively monotonous round‐to‐short spindle tumor cells and taper‐shaped tumor cells are observed in the female genital tract, high‐grade endometrial stromal sarcoma should be considered in the differential diagnosis. Immunocytochemistry contributed to the correct diagnosis. This case was high‐grade endometrial stromal sarcoma with smooth muscle and skeletal muscle differentiation. Diagn. Cytopathol. 2010.

Expression of matrix metalloproteinase-7 correlates with the invasion of T1 colorectal carcinoma

T1 colorectal carcinomas (CRCs) are an initial site of metastatic spread. Various risk factors for lymph node metastasis have been investigated in T1 CRCs. However, the major step in the entire process of metastasis remains unclear. In terms of carcinoma invasion and metastasis, matrix metalloproteinases (MMPs) have recently gained increasing attention. Notably, MMP-7 is frequently overexpressed in CRCs, but its implication has not been determined in T1 CRCs yet. The present study aimed to clarify the associations between the pathological risk factors of T1 CRCs and MMP-7. In the current study, 211 lesions of T1 CRC that were resected endoscopically or surgically at Showa University Northern Yokohama Hospital (Yokohama, Japan) between April 2008 and December 2009 were retrospectively analyzed. MMP-7 was immunostained and evaluated by its frequency of expression. Pathological factors of T1 CRCs were analyzed in association with MMP-7 expression. Furthermore, the ultrastructural alterations of carcinoma invasion were examined using low vacuum-scanning electron microscopy (LV-SEM). MMP-7 expression was associated with venous invasion (P=0.005), and LV-SEM revealed the disappearance of the normal structure of collagen and elastic fibers of veins invaded by tumor cells expressing MMP-7. At the invasive front, MMP-7 has a vital role in carcinoma invasion, correlating with venous invasion of T1 CRCs.