Yasushi Horie

Association of Merkel cell polyomavirus infection with clinicopathological differences in Merkel cell carcinoma.

Merkel cell polyomavirus is a novel polyomavirus that is monoclonally integrated into genomes of up to 80% of human Merkel cell carcinomas. Merkel cell polyomavirus-positive Merkel cell carcinomas showed less metastatic tendency and better prognosis according to some reports, whereas others disagree. In this study, we analyzed clinicopathological characteristics of 20 Merkel cell polyomavirus-positive and 6 Merkel cell polyomavirus-negative Merkel cell carcinoma cases, in which we already reported the association of Merkel cell polyomavirus infection with statistically significant morphological differences. Immunohistochemical expressions of cell cycle-related proteins, mutations of the TP53 tumor-suppressor gene (exons 4-9) and p14ARF promoter methylation status as well as detailed clinical data were analyzed and compared between Merkel cell polyomavirus-positive and Merkel cell polyomavirus-negative cases. Merkel cell polyomavirus-positive Merkel cell carcinomas showed better prognosis with one spontaneous regression case and significantly higher expression of retinoblastoma protein (P = .0003) and less p53 expression (P = .0005) compared to Merkel cell polyomavirus-negative Merkel cell carcinomas. No significant differences were found in expressions of p63, MDM2, p14ARF or MIB-1 index, and p14ARF promoter methylation status. Interestingly, frequency of TP53 non-ultraviolet signature mutation was significantly higher in Merkel cell polyomavirus-negative Merkel cell carcinomas than in Merkel cell polyomavirus-positive Merkel cell carcinomas (P = .036), whereas no significant difference was detected in TP53 ultraviolet signature mutations between two groups. These results suggest that Merkel cell polyomavirus-positive and -negative Merkel cell carcinomas likely develop through different tumorigenic pathways and that the presence or absence of Merkel cell polyomavirus in the tumor is still an important factor that affects survival in patients with Merkel cell carcinoma.

Hepatocellular carcinoma with sarcomatous change arising after radiofrequency ablation for well-differentiated hepatocellular carcinoma.

We report a case involving well-differentiated hepatocellular carcinoma (HCC) developing to HCC with sarcomatous changes after radiofrequency ablation (RFA). In a cirrhotic patient with both hepatitis B surface antigen and hepatitis C virus RNA, a well-differentiated HCC with a diameter of 2 cm was detected in segment IV of the liver. A combination of transcatheter arterial embolization and percutaneous ethanol injection (PEI) was performed and, after 8 months, PEI was performed for recurrent tumors. Fifteen months after the first treatment, a recurrent tumor measuring 3.5 cm in diameter was detected in segment IV, which was demonstrated as well-differentiated HCC by tumor biopsy, and treated by RFA. Although the treated lesion was reduced to 2.5 cm in diameter 6 months after RFA, the tumor rapidly enlarged to 6 cm in diameter 2 months later and progressed to lymph node metastasis. Aspiration biopsy showed spindle-shaped sarcomatoid cells with positive staining for both vimentin and keratin. The patient died of HCC progression 10 months after RFA. Autopsy findings showed both sarcomatoid cells and trabecular HCC cells. The sarcomatoid cells had metastasized to the lymph nodes and distant organs. This is the first case illustrating a sarcomatous HCC after RFA. Of interest, RFA may be related to the development of sarcomatous HCC.

Lymphatic vessel density in pulmonary adenocarcinoma immunohistochemically evaluated with anti-podoplanin or anti-D2-40 antibody is correlated with lymphatic invasion or lymph node metastases

In lung cancers, lymph node metastasis of cancer cells is one of the most important prognostic factors, and lymphatic vessel invasion (LVI) is very important in the stage preceding lymph node metastases. Recently, it has been reported that lymphatic vessel density (LVD) is associated with lymph node metastasis. The aim of the present study was to evaluate the relationship between LVD and LVI based on the immunohistochemical expression of podoplanin or D2‐40, which are new specific markers for lymphatic endothelium. Using 76 cases of pulmonary adenocarcinoma, the relationship between LVD and LVI, lymph node metastases, vascular endothelial growth factor C (VEGF‐C), VEGF‐D or hepatocyte growth factor (HGF) expression was investigated. LVD was significantly associated with LVI, lymph node metastases and VEGF‐D expression. LVI was also associated with lymph node metastases, histological subtype, VEGF‐C or VEGF‐D expression. High LVD, induced by VEGF‐C or VEGF‐D expression of cancer cells, is a good indicator of lymphatic metastases and LVI in pulmonary adenocarcinoma.

Peripheral primitive neuroectodermal tumor of the small bowel mesentery: A case showing perforation at onset

A case of peripheral primitive neuroectodermal tumor of the small bowel mesentery with an uncommon clinical onset is reported. A 40‐year‐old man was admitted to hospital because of acute severe abdominal pain. Chest X‐ray revealed a free air sign beneath the diaphragm. At emergency surgery a mass measuring 11.0 × 8.0 cm with perforation was located in the jejunal mesenteric region. Histologically the resected lesion consisted of sheets of undifferentiated small round cells forming abortive Homer Wright rosettes. Some spindle‐shaped cells showed perivascular pseudorosettes. Immunohistochemical study revealed that the tumor cells expressed positivity against CD99 (MIC2), neuron‐specific enolase, synaptophysin and vimentin. To the authors’ knowledge this is the first documentation of peripheral primitive neuroectodermal tumor of the small bowel mesentery with perforation at onset.

Detection of Merkel cell polyomavirus in the human tissues from 41 Japanese autopsy cases using polymerase chain reaction.

It has recently been shown that approximately 80% of Merkel cell carcinomas harbor a novel polyomavirus named Merkel cell polyomavirus (MCPyV). MCPyV has been detected in human tissue samples. However, detailed distribution of MCPyV in non-neoplastic Japanese human tissues remains unclear. To address this, we used single or real-time quantitative polymerase chain reaction (PCR) for 41 autopsy cases. PCR revealed MCPyV-DNA in non-neoplastic samples: total, 29/41 (71%); adult, 29/39 (74%); fetus or infant, 0/2; men, 24/28 (86%); women, 5/13 (38%); total human tissues, 66/572 (12%); skin, 8/15 (53%); adrenal gland, 9/33 (27%), and other 16 organs (4–25%). This study first reported the presence of MCPyV-DNA in non-neoplastic tissues of thyroid gland, adrenal gland, spleen, bone marrow, stomach, gallbladder, pancreas, heart, and aorta. PCR revealed that viral load ranged from 0.00026 to 0.22 in all MCPyV-positive tissues compared with Merkel cell carcinoma samples. These detailed PCR data showed higher prevalence of MCPyV infection in Japanese men than women (p = 0.004) and broad distribution of MCPyV with low viral load in more non-neoplastic human tissues than in the previous reports. These data provide valuable insights for further studies of MCPyV infection and MCPyV-related diseases.

Pseudovascular squamous cell carcinoma of the uterine cervix: a lesion that may simulate an angiosarcoma.

A case of pseudovascular squamous cell carcinoma in the uterine cervix of a 64‐year‐old woman was examined. Histologically, the lesion consisted of atypical, large, non‐keratinizing squamous cells that exhibited not only acantholytic changes but also pseudovascular changes. Immunohistochemically, these tumor cells were positive for cytokeratin, epithelial membrane antigen and carcinoembryonic antigen, but none of them were positive for Factor VIII‐related antigen or CD34. To our knowledge, pseudovascular carcinoma of the uterine cervix has not been described in the literature. Pathologists should be aware of this unusual form of cervical squamous cell carcinoma, particularly in the differential diagnosis of angiosarcoma.

Uterus-like mass of the small bowel mesentery

A case of a uterus‐like mass arising from the mesentery is reported. A mass measuring 14 × 11 cm was noted in the small bowel mesentery of a 59‐year‐old woman. Histologically, the lesion consisted of endometrial‐type and fallopian tube‐type mucosa surrounded by thick bundles of smooth muscle cells. Since the first report by Cozzutto in 1981, 10 cases of uterus‐like mass, that included seven ovarian and three extraovarian cases, have been reported. To our knowledge, the present lesion was the first case originating from the mesenteric region. Three hypotheses of this rare lesion: (i) congenital anomaly; (ii) metaplasia; and (iii) heterotopia theories are reviewed.

Spindle cell hemagioendothelioma: A report of two cases

Two cases of spindle cell hemangioendothelioma (SCH) are reported. One of the patients was a 16 year old Japanese female, who had been suffering from Olliers disease (multiple enchondrornatosis) since 3 years of age and had developed multiple SCH in the right leg at the age of 11 years. Spindle cell hemangioendothelioma lesions coincided with the site of enchondromatosis and increased in number thereafter. This is the first report of Olliers disease complicated with multiple SCH. Another patient, a 33 year old Japanese female, who was a carrier of hepatitis B virus (HBV), developed solitary SCH in the lateral aspect of the right ankle where a lipoma was extirpated 10 years previously. Tumor cells of both cases were composed of four cell types: (i) spindle cells; (ii) epithelioid cells; (iii) vacuolated endothelial cells; and (iv) usual endothelial cells. Endothelia in the cavernous area and vacuolated cells reacted to Ulex europaeus agglutin 1 (UEA‐I), factor VIII‐related antigen and vimentin. Spindle cells and epithelioid cells reacted only to vimentin.

Merkel cell polyomavirus DNA sequences in peripheral blood and tissues from patients with Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH) is a group of granulomatous disorders in which abnormal Langerhans cells proliferate as either a localized lesion in a single bone or disseminated disease involving two or more organs or systems. Because the different LCH forms exhibit significantly elevated levels of inflammatory molecules, including pro-inflammatory cytokines and tissue-degrading enzymes, we investigated for a possible viral trigger in LCH pathogenesis. We looked for Merkel cell polyomavirus (MCPyV) in peripheral blood cells and tissues using quantitative real-time PCR and immunohistochemistry staining with anti-MCPyV large T-antigen antibody. Our findings revealed elevated amounts of MCPyV DNA in the peripheral blood cells of 2 of 3 patients affected by LCH with high-risk organ involvement (RO+) and absence of MCPyV DNA in the blood cells in all 12 LCH-RO- patients (P = .029). With lower viral loads (0.002-0.033 copies/cell), an elevated number of MCPyV DNA sequences was detected in 12 LCH tissues in comparison with control tissues obtained from patients with reactive lymphoid hyperplasia (0/5; P = .0007), skin diseases not related to LCH in children younger than 2 years (0/11; P = .0007), or dermatopathic lymphadenopathy (5/20; P = .0002). The data, including frequent but lower viral loads and low large-T antigen expression rate (2/13 LCH tissues), suggest that development of LCH as a reactive rather than a neoplastic process may be related to MCPyV infection.

IL-17A receptor expression differs between subclasses of Langerhans cell histiocytosis, which might settle the IL-17A controversy

Langerhans cell histiocytosis (LCH) is a lymphoproliferative disorder consisting of abnormal Langerhans cell-like cells and other lymphoid cells. LCH presents as either a multisystem LCH (LCH-MS) or a single-system LCH (LCH-SS). Currently, neither the pathogeneses nor the factors that define these disease subclasses have been elucidated. The interleukin (IL)-17A autocrine LCH model and IL-17A-targeted therapies have been proposed and have engendered much controversy. Those authors showed high serum IL-17A levels in LCH and argued that serum IL-17A-dependent fusion activities in vitro, rather than serum IL-17A levels, correlated with LCH severity (i.e. the IL-17A paradox). In contrast, others could not confirm the IL-17A autocrine model. So began the controversy on IL-17A, which still continues. We approached the IL-17A controversy and the IL-17A paradox from a new perspective in considering the expression levels of IL-17A receptor (IL-17RA). We detected higher levels of IL-17RA protein expression in LCH-MS (n = 10) as compared to LCH-SS (n = 9) (P = 0.041) by immunofluorescence. We reconfirmed these data by re-analyzing GSE16395 mRNA data. We found that serum levels of IL-17A were higher in LCH (n = 38) as compared to controls (n = 20) (P = 0.005) with no significant difference between LCH subclasses. We propose an IL-17A endocrine model and stress that changes in IL-17RA expression levels are important for defining LCH subclasses. We hypothesize that these IL-17RA data could clarify the IL-17A controversy and the IL-17A paradox. As a potential treatment of LCH-MS, we indicate the possibility of an IL-17RA-targeted therapy.