Total endoscopic thyroidectomy after open neck biopsy of the follicular lymphoma of the thyroid gland

Remote-access total endoscopic thyroidectomy (TET) is a recently established approach that can avoid producing scars in the neck. There are no clear surgical indications for TET for benign nodules or for malignant tumors at present. We report a successful TET in a 50-year-old Japanese woman with follicular lymphoma of the thyroid gland after an open neck biopsy. She had been referred to us with a neck tumor noted 2 months earlier. Because of adhesion, we performed a combined resection of the thyroid and partial right sternohyoid muscle. To the best of our knowledge, there is no other report of a TET performed after open neck surgery. Our patient's case demonstrates that (a) the cosmetic outcome of TET is clearly superior to that of conventional open neck surgery, and (b) a TET can be suitable even for reoperation if carefully selected.

A novel mutation of the FAT2 gene in spinal meningioma

Meningiomas may be classified as neurofibromin 2 (NF2)-associated and non-NF2 meningiomas depending on the presence or absence of molecular alterations in the NF2 gene. One of the characteristic histological features of meningiomas is the whorl formation of neoplastic arachnoid cells. NF2 is a human homolog of the Drosophila gene, Merlin (Mer). In humans, NF2 is the gene responsible for the disease neurofibromatosis type II, which results in the development of brain tumors, including acoustic neurinoma and meningioma. The present study aimed to investigate the molecular pathogenesis of spinal meningioma. It was hypothesized that the whorl formation of meningiomas may occur as a result of a disturbance in the planar cell polarity (PCP) of arachnoid cells, thus, genes understood to govern PCP signaling were analyzed for alterations. Whole exome sequencing followed by Sanger sequencing validation was performed for the analysis of spinal meningioma tissue obtained from a 42-year-old Japanese female. The sequencing identified a nonsynonymous mutation of c.3597G>C, resulting in p.Q1199H, in the FAT atypical cadherin 2 (FAT2) gene. FAT2 is homologous to the Drosophila Fat (Ft) gene, which belongs to the cadherin superfamily. Drosophila Fat is involved in PCP, tumor suppression and Hippo (Hpo) signaling, which is associated with Mer. Taken together, the results of the present study concluded that human FAT2 may function as a key molecule that governs not only PCP, but also NF2-Hpo signaling in arachnoid cells; thus, a mutation in this gene may result in spinal meningioma.

Biallelic disruption of the PTCH1 gene in multiple basal cell carcinomas in Japanese patients with nevoid basal cell carcinoma syndrome

The aim of the present study is to address whether the molecular pathogenesis is identical among multiple basal cell carcinomas (BCCs) present in the same nevoid basal cell carcinoma syndrome (NBCCS) patient. Patient 1 is a 61-year-old (yo) Japanese female whose clinical characteristics and findings of a genetic analysis of PTCH1 have been previously described. Patient 2 is patient 1's 64-yo sister who also suffered from NBCCS with a single base deletion at nucleotide 2613 in exon 16 (c.2613delC) in one PTCH1 allele. Thirteen and 3 independent specimens of BCC were applied for a molecular analysis of loss of heterozygosity (LOH) in PTCH1 in patients 1 and 2, respectively. Of particular note is that all BCC specimens examined showed a loss of the wild-type allele of exon 16 in PTCH1, thus indicating that LOH results in the biallelic disruption of PTCH1 in multiple BCCs that develop in an age- and location-independent manner in the same patient. These results indicate that the germline single base deletion of PTCH1 (c.2613 delC) is a first hit and the LOH of the wild-type allele is a second hit, implying that all 16 BCCs detected in these NBCCS sisters fit the standard two-hit model.

Neuroendocrine carcinoma arising in a hepatitis C virus-infected liver: mechanism of the tumor development may be similar to that of development of pancreatic neuroendocrine cells

We experienced a case of neuroendocrine carcinoma (NC). The tumor developed in the cirrhotic liver of a 62-year-old Japanese man who had been infected with hepatitis C virus. The tumor cells showed high N/C ratio, formed many rosettes, and expressed CD56, synaptophysin, HepPar1 and pancreatic and duodenal homeobox 1. MIB1 expression was 65%. Because both liver and pancreas are derived from a common endodermal layer during fetal development, we speculated that the tumor may have formed via the interaction of neurogenin 3, insulinoma-associated 1 gene and NeuroD/beta2, which are involved in the stage at which some pancreatic cells commit to becoming endocrine cells. Molecular analysis revealed that the NC had higher relative expression levels of mRNA of the three molecules than did the nontumorous liver. The results indicate that the NC in this patient may have formed via the same mechanism that acts in the development of pancreatic neuroendocrine cells.

Biallelic alterations of the large tumor suppressor 1 (LATS1) gene in infiltrative, but not superficial, basal cell carcinomas in a Japanese patient with nevoid basal cell carcinoma syndrome

The present study was conducted to address the molecular pathogenesis underlying the progression of basal cell carcinoma (BCC) in a nevoid basal cell carcinoma syndrome (NBCCS) patient. We analyzed infiltrative BCCs that invaded the subcutaneous tissue of the scalp and penetrated the skull in a 61-year-old Japanese female. Whole-exome sequencing validated by Sanger sequencing was applied to assess the subcutaneously infiltrative BCCs. Differences in genetic alterations between the superficial and infiltrative BCCs were also examined. Of particular note, the infiltrative BCCs showed a nonsense mutation, c.943C>T, resulting in p.Q315X in the large tumor suppressor 1 (LATS1) gene, as well as the loss of the wild-type allele of LATS1 (6q25.1), thus indicating that the LATS1 gene was biallelically disrupted. In contrast, no alterations in the LATS1 gene were observed in the superficial BCCs. Additionally, a loss of heterozygosity analysis revealed that the distal region of chromosome 6q where LATS1 locates was deleted in a heterozygous manner. The present results imply that the biallelic disruption of LATS1 is a progressive factor of the infiltrative BCCs observed in this NBCCS patient and suggest that the Hippo pathway is a potential therapeutic target in cases of infiltrative BCC.

Diagnostic challenge: intraductal neoplasms of the pancreatobiliary system

To help pathologists avoid misdiagnosis of intraductal neoplasms arising from the pancreatobiliary system, we report two cases that illustrate diagnostic pitfalls. The first is of a 66-year-old man who complained of appetite loss. An early examination led to a diagnosis of intraductal papillary mucinous neoplasm. Macroscopically, a multilocular cyst without visible mucin was identified. Histologically, the compartments consisted of complex fusion of tubular glands surrounded by dilated pancreatic duct. The neoplasm resembled an acinar cell cystadenocarcinoma. However, the neoplastic cells were negative for trypsin. Thus, the final histopathologic diagnosis was an unusual cystic variant of intraductal tubulopapillary neoplasm (ITPN) of the pancreas. The second case is of a 71-year-old man who complained of right upper quadrant pain. Although bile duct stone was suspected, a polypoid nodule was extracted. Histologically, the nodule was composed of tubular glands, with some complex fusion and focal dysplasia, consistent with carcinoma. In addition, lack of MUC-5AC expression led to an initial impression of ITPN of the bile duct. However, the neoplasm showed dysplastic cells based on the columnar cells resembling pyloric glands, indicating the sequential progression. Thus, the final histopathological diagnosis was intraductal papillary neoplasm of the bile duct with high-grade intraepithelial neoplasia. Because phenotypic variants of intraductal neoplasms of the pancreatobiliary system exist, ITPN and ITPN-mimicking tumor must be carefully differentiated from other intraductal neoplasms.

A case of pulmonary papillary adenoma: possible relationship between tumor histogenesis/tumorigenesis and fibroblast growth factor receptor 2 IIIb

Pulmonary papillary adenoma is a rare tumor. We analyzed a tumor which appeared in a 16-year-old Japanese woman. The tumor histologically showed papillary proliferation of one-layered tumor cells coating inflammatory fibrovascular cores. At the periphery of the tumor, the tumor cells grew in a lepidic fashion. The tumor cells were confirmed as type-II pneumocytes with electron-microscope. In this study, using immunohistochemistry, in situ hybridization and real-time reverse transcription polymerase chain reaction, we examined the expressions and quantities of fibroblast growth factor 10 (FGF10), keratinocyte growth factor (KGF) and fibroblast growth factor receptor 2 (FGFR2) IIIb, based on the extent of their abilities of proliferation and differentiation of type II pneumocytes. The tumor cells expressed FGFR 2 and produced 350 times more FGFR2IIIb messenger RNA (mRNA) than did the nontumorous lung. The quantity of KGF mRNA in the tumor tissue was twice that of the nontumorous lung. Moreover, there was dysregulation of FGFR2IIIb transcription in the tumor. According to these findings, we expect overexpression of FGFR2IIIb to play an important role in causing tumor. Because FGFR is suspected to be connected with lung carcinoma, we also treat similar tumorigenesis via FGFR as carcinoma; complete resection of adenoma might be indicated.

Autopsy cases of miliary tuberculosis: clinicopathologic features including background factors

To assist physicians, especially young physicians, in identifying tuberculosis (TB) infection before the terminal stage, we analyzed 7 cases of numerous tuberculous granulomas in multiple organs and compared clinical and autopsy findings between cases. Patients ranged in age from 41 to 86 years at the time of death. The main chief complaint was fever of unknown origin (3 of 7 cases [43%]). The main underlying conditions were liver cirrhosis (2 of 7 cases [29%]) and chronic renal failure (2 of 7 cases [29%]). Two patients (29%) had been given methylprednisolone pulse therapy for various lung disorders. Active TB was not diagnosed before autopsy in 4 of 7 (57%) patients. Calcified lesions indicative of old TB were present in 4 of 7 (57%) patients. Thus, miliary tuberculosis may represent a re-emergence of latent TB infection in these cases. Various histologic features of nonreactive exudative inflammation were seen, along with granulomas containing Langhans giant cells with or without caseous necrosis in hypervascular organs, such as the lung, liver, and bone marrow. Physicians should be mindful of the possibility of miliary TB when older patients with hepatorenal disease and a history of TB infection have undergone immunosuppressive treatment. Active tuberculous infection can depend on the presence of an underlying disease and immunocompromise.

Autopsy cases of fulminant bacterial infection in adults: clinical onset depends on the virulence of bacteria and patient immune status

To assist physicians in recognizing the potentially fatal onset of symptoms in cases of fulminant bacterial infection, we analyzed 11 autopsy cases of such infection (four caused by Streptococcus pneumoniae, four by S. pyogenes, one by S. dysgalactiae subsp. equisimilis, one by Staphylococcus aureus, and one by Vibrio vulnificus). Clinicohistopathologic features were evaluated. All patients experienced sudden onset of hypotension and multiple organ failure, leading to unexpected death. Blood culture confirmed bacteremia. The main chief complaints were gastrointestinal symptoms (45%) and limb pain (36%). All had an underlying chronic illness (82%), e.g., a hematologic disorder (36.3%) or liver cirrhosis (27.2%). Necrotizing fasciitis occurred in only 55% of cases, with none involving pneumococcal infection. Laboratory tests typically showed C-reactive protein elevation but without leukocytosis, indicating a high-level inflammatory state. In ten cases, death was attributed to circulatory collapse due to sepsis; severe pulmonary congestion and hemorrhage were present in these cases. The onset of fulminant bacterial infection depends on both virulence of the bacterium and status of the host defense system.

Comparison of immunocytochemical sensitivity between formalin-fixed and alcohol-fixed specimens reveals the diagnostic value of alcohol-fixed cytocentrifuged preparations in malignant effusion cytology

The most commonly used fixative in effusion cytology is formalin. In the present study, the immunocytochemical properties of formalin-fixed and alcohol-fixed specimens were compared to evaluate the usefulness of alcohol-fixed cytocentrifuged preparations for routine cytologic diagnosis. A total of 269 effusion samples and 17 primary antibodies were used. The sensitivity of immunocytochemical studies in alcohol-fixed specimens was similar and correlated to that of formalin-fixed specimens, suggesting that alcohol-fixed cytocentrifuged preparations are useful in effusion cytology. Pretreatment with or without heat-induced antigen retrieval revealed that antigen retrieval was unnecessary for immunocytochemical studies with most primary antibodies in alcohol-fixed cytocentrifuged preparations. The present study describes the use of immunocytochemical studies with alcohol-fixed cytocentrifuged preparations for diagnosis in routine effusion cytology.

A case of granulocyte colony-stimulating factor and interleukin 6 receptor-producing mediastinal mature cystic teratoma with somatic-type malignancy

Mediastinal germ cell tumor with somatic-type malignancy is a rare neoplasm. We describe one such case in a 49-year-old Japanese man who had shown an elevated serum concentration of granulocyte colony-stimulating factor (GCSF) and leukocytosis without a shift to the left. Histologically, the tumor formed a teratomatous cyst whose wall contained benign epithelial components, well-differentiated tubular and mucinous adenocarcinoma, and poorly-differentiated pleomorphic carcinoma. Immunohistochemically, both the well differentiated adenocarcinoma and poorly differentiated pleomorphic carcinoma expressed GCSF. Immunohistochemistry and molecular analysis revealed that both components also produced interleukin 6 receptor (IL6R). We diagnosed this tumor as a GCSF- and IL6R-producing mediastinal mature cystic teratoma with somatic-type malignancy. The tumor showed immunohistochemical expression of activated signal transducer and activator of transcription 3. The patient died 6 months after developing systemic symptoms. For a GCSF-producing tumor, complete resection appears to offer the best outcome at present. For any patient presenting with leukocytosis without a shift to the left, a thorough analysis should be conducted, and the tumor diagnosed as early as possible.

Multiple immunoenzyme labeling using heat treatment combined with the polymer method: an analysis of the appropriate inactivation conditions of primary antibodies

Multiple immunoenzyme labeling is of considerable value to detect several antigens in the same specimen, although this technique is limited when the primary antibodies have been raised in the same animal species. Multiple immunoenzyme labeling using heat treatment is a simple, reliable and straightforward technique wherein the heat treatment prevents mixed labeling and cross-reaction. The present study determined the inactivation time for primary antibodies by heat treatment in order to apply this procedure to routine histopathological diagnosis and research, and found that the inactivation time differed among the primary antibodies. The secondary antibodies and the labeling enzyme were completely inactivated by heating for 10 min. Therefore, the inactivation of the primary antibodies is crucial to perform multiple immunoenzyme labeling using heat treatment. The sequential combination of the primary antibodies is also important; in the study presented here, an anti-thyroid transcription factor-1 (TTF-1) antibody should be used first and anti-cytokeratin AE1/AE3 antibody second, but not in the opposite sequence, to avoid a mixed-colour-labeling reaction. The present data provided the optimum combination of primary antibodies for multiple immunoenzyme labeling using heat treatment.

Cytologic features and frequency of plasmacytoid dendritic cells in the lymph nodes of patients with histiocytic necrotizing lymphadenitis (Kikuchi-Fujimoto disease)

Histiocytic necrotizing lymphadenitis (HNL), also known as Kikuchi-Fujimoto disease, is a benign and self-limiting disease. It is histologically characterized by nodal lesions that show the infiltration of histiocytes, lymphoid cells, myeloid dendritic cells (mDCs), and plasmacytoid dendritic cells (pDCs), along with either apoptotic or karyorrhexic nuclear debris. pDCs have been proposed to be lymphoid early-committed immature DCs which are positive for CD123, CD303, CD68, and HLA-DR but negative for fascin, a mature DC marker, as well as CD13 and CD33,which are mDC markers. In the present study, we analyzed the cytomorphologic features and frequency of pDCs in the lymph nodes of HNL patients. Because the cytologic apprearance of pDCs with Papanicolau staining was quite similar to that of large lymphocytes, immunocytochemistry against CD123 was necessary for the distinction of pDCs. Counting the number of CD123-positive pDCs in the HNL lymph nodes revealed that pDCs more frequently infiltrated the lymph nodes in the setting of HNL than in either reactive lymphadenitis or T and B cell lymphoma. In addition, interestingly, the numberof pDCs did not depend on the age of the HNL lesion, thus suggesting that pDCs are excellent indicators for the cytologic diagnosis of HNL.

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.

Involvement of IL-17F via the induction of IL-6 in psoriasis

Recently, the important role of T helper 17 (Th17) cells in psoriasis has been clarified; however, the role of IL-17F produced by Th17 cells is still not fully understood. IL-6 exhibits multiple biologic functions, such as regulation of immunological responses including those in psoriatic reactions. Therefore, we examined the production of IL-6 protein in normal human epidermal keratinocytes (NHEKs) stimulated by IL-17F, TNF-alpha, IL-17A, and IL-17A in combination with TNF-alpha, and PBS control. We then examined the expression of IL-6 mRNA in mouse skin after intradermal injection of IL-17F. Finally, IL-17F expression in skin biopsy specimens from psoriasis patients was examined by immunohistochemistry. The results showed that IL-17F induced production of IL-6 in NHEKs in a time-dependent manner. This could be attenuated by chimeric inhibitor blocking the IL-17 receptor. The amounts of IL-6 stimulated by IL-17F were much higher than those stimulated by TNF-alpha or IL-17A. IL-6 was also significantly upregulated via synergistic stimulation with IL-17A plus TNF-alpha. The expression of IL-6 mRNA 24 h after IL-17F injection in the mouse skin was 3.2-fold higher than that in the control group. Immunohistochemistry of inflammatory cells in the dermis demonstrated a large number of CD4(+) T cells showing IL-17F positivity in psoriatic skin lesions, but few or none in non-lesional psoriatic skin. Our results indicate that IL-17F produced by CD4(+) T cells causes the inflammation in psoriasis partly through induction of IL-6 in keratinocytes.

IMP3/L523S, a novel immunocytochemical marker that distinguishes benign and malignant cells: the expression profiles of IMP3/L523S in effusion cytology

Differentiating reactive mesothelial cells from metastatic carcinoma and malignant mesothelioma is critical in effusion cytology. Numerous immunohistochemical/cytochemical reports use various antibodies in effusion samples, and most antibodies differentiate metastatic adenocarcinoma from malignant mesothelioma, but no antibodies help distinguish malignant mesothelioma from reactive mesothelial cells. A mouse monoclonal antibody (IMP3/L523S) against KOC is a 580-amino acid oncofetal RNA-binding protein containing 4 K homology domains. IMP3/L523S has been identified in several human malignant tumors. The immunocytochemical staining profile of IMP3 was determined in 95% alcohol-fixed cytologic effusion specimens. A total of 229 cases of pleural and peritoneal effusion cytospecimens were evaluated for the study, including 39 benign effusions with reactive mesothelial cells and 190 metastatic malignant effusions. IMP3 immunoreactivity was observed in 2 (5.1%) of 39 cases of reactive mesothelial cells, 138 (72.6%) of 190 cases of malignant effusion, 4 (36.4%) of 11 cases of malignant mesothelioma, 106 (75.7%) of 140 cases of metastatic adenocarcinoma, and 8 (100%) of 8 cases of squamous cell carcinoma. The overall specificity for the diagnosis of malignancy was 94.9%, whereas the sensitivity was 72.6%. In the peritoneal effusions, the sensitivity for the diagnosis of metastatic adenocarcinoma to distinguish reactive mesothelial cells was 92.3%. In conclusion, IMP3 staining is present in many carcinomas and is not a useful marker for distinguishing between carcinomas arising in different organs. However, the IMP3 antibody is a highly specific marker for malignant lesions, and thus, IMP3 staining is useful for distinguishing neoplastic cells from reactive mesothelial cells in effusion samples.

Allelic loss of the PTEN gene and mutation of the TP53 gene in choriocarcinoma arising from gastric adenocarcinoma: analysis of loss of heterozygosity in two male patients with extragonadal choriocarcinoma

A tumor suppressor gene at 10q23.3, designated PTEN, encoding a dual-specificity phosphatase with lipid and protein phosphatase activity, has been shown to play an essential role in the pathogenesis of a variety of human cancers. Frequent mutations and deletions of PTEN genes are found in cancer. Little is known, however, about the role that PTEN plays in the pathogenesis of a primary choriocarcinoma derived from gastric adenocarcinoma, an extremely rare choriocarcinoma, or in extragonadal retroperitoneal choriocarcinoma. In this study, genetic alterations occurring in extragonadal choriocarcinoma in two Japanese male patients were examined. Loss of heterozygosity (LOH) analysis using a polymorphic marker of the PTEN gene, IVS4+109ins/delTCTTA, revealed a hemizygous deletion of PTEN not only in the primary gastric choriocarcinoma, but also in the gastric adenocarcinoma. Microsatellite marker D12S1051 likewise showed LOH in both the primary gastric choriocarcinoma and the gastric adenocarcinoma. Mutational analysis of the TP53 gene revealed a point mutation in exon 5 (A536G), which resulted in H179R in the gastric choriocarcinoma but not in the gastric adenocarcinoma. No LOH was found for PTEN in an extragonadal retroperitoneal choriocarcinoma. Microsatellite marker D9S162 showed LOH in the extragonadal retroperitoneal choriocarcinoma, but not in the primary gastric choriocarcinoma. These results indicate that LOH of the PTEN gene and of D12S1051 is the molecular pathogenesis of the gastric adenocarcinoma, and the mutation of the TP53 gene is an additional hit for the oncogenesis of choriocarcinoma arising from gastric adenocarcinoma. However, LOH of the PTEN gene is not a common molecular event for pathogenesis of extragonadal choriocarcinoma. In addition, it was found that expression of PTEN is significantly decreased in the nuclei of syncytiotrophoblast-like cancer cells, compared with those of cytotrophoblast-like cancer cells in choriocarcinoma.

[A case of MALT lymphoma simultaneously associated with gastric and pulmonary involvement]

A 52-year-old man had been treated by hemodialysis because of IgA nephropathy since 1994. Gastric MALT lymphoma was diagnosed in January 2007. Radiation therapy was performed for 4 weeks (40Gy) and the response was complete remission (CR) by September 2007. He was admitted to our hospital in February 2008 because of an abnormal chest shadow. Chest CT showed multiple cystic lesions with calcification and consolidation. Transbronchial lung biopsy from the area of consolidation (left S5) showed pulmonary invasion of small lymphoid cells. PCR analysis showed clonal rearrangement of the heavy chain of the immunoglobulin gene. Accordingly, MALT lymphoma was diagnosed. Rituximab infusion was performed, because CD20 immunostaining was positive and he had been treated by hemodialysis. The abnormal chest shadow was presented since gastric MALT lymphoma was diagnosed. We considered that MALT lymphoma occurred simultaneously in the stomach and lung.

Mutations of the KIT gene and loss of heterozygosity of the PTEN region in a primary malignant melanoma arising from a mature cystic teratoma of the ovary

A tumor suppressor gene at 10q23.3, designated PTEN, encoding a dual-specificity phosphatase with lipid and protein phosphatase activity, has been shown to play a pivotal role in the pathogenesis of a variety of human cancers. A frequent loss of heterozygosity (LOH) at 10q is found in melanoma; however, little is known about the role of PTEN in the pathogenesis of a primary malignant melanoma derived from ovarian mature cystic teratoma, which is an extremely rare melanoma. This study examined the genetic alterations involved in the mitogen-activated protein kinase and phosphatidylinositol 3 kinase pathways in an ovarian malignant melanoma. A LOH analysis revealed hemizygous deletion around and in the PTEN gene not only in the ovarian melanoma but also in a mature cystic teratoma. Another case of ovarian mature cystic teratomas in the absence of melanoma also showed allelic loss of the PTEN region. To date, mutations of BRAF, NRAS, and KIT genes have been reported in malignant melanomas. In the present study, D816H and K558E mutations of the KIT gene were revealed in the melanoma arising from a mature cystic teratoma, but not in a mature cystic teratoma. No mutations of the BRAF and NRAS genes were found in the melanoma. These results indicate that LOH of the PTEN region is one of the molecular alterations of an ovarian mature cystic teratoma and a KIT mutation is an additional promotional event associated with the oncogenesis of a melanoma arising from an ovarian mature cystic teratoma.

A novel mutation of the PTEN gene in a Japanese patient with Cowden syndrome and bilateral breast cancer

Cowden syndrome (CS), also known as multiple hamartoma syndrome, is an autosomal dominant cancer syndrome associated with a high risk of breast and thyroid cancers. The phosphatase and tensin homolog gene (PTEN) encodes a lipid phosphatase that contains a PTPase domain and a C2 domain and plays a role as a tumor suppressor that negatively regulates the cell-survival signaling pathway initiated by phosphatidylinositol 3-kinase (PI3K). PTEN inhibits angiogenesis, and germline mutations of the PTEN gene are associated with CS. We screened for mutations in the PTEN gene in two unrelated Japanese patients with CS. In one patient, who suffered from bilateral breast cancer, thyroid adenoma, and gastric malignant lymphoma, we found a single-base substitution in exon 2 (115G>C) of the PTEN gene. This transversion results in a germline missense mutation (A39P). To date, nine different mutations have been identified in exon 2 of the PTEN gene in patients with CS and variant CS; however, the A39P missense mutation has not been reported previously. We also detected a previously reported nonsense mutation, 697C>T, resulting in R233X.

Thymic epithelial cells expressed unusual follicular dendritic cell markers: thymic extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue

Described herein is a case of thymic extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue. Using immunohistochemical double staining it was found that most of the thymic lymphoid follicles in this case possessed cytokeratin-positive and follicular dendritic cell (FDC) marker-positive cells. Moreover, using immunoelectron microscopy it was confirmed that some of the double-positive cells were thymic epithelial cells. The candidate of cytokeratin subtype expressed on the double-positive cells was cytokeratin 1 (CK1), which was expressed only by the epithelium of Hassall's corpuscles in thymuses from age-matched patients with myasthenia gravis. The present case indicates a possibility that some thymic epithelial cells become FDC, although it was uncertain whether they were derived from the epithelia of Hassall's corpuscles or whether they were at the same differentiation stage as Hassall's corpuscles.

Coordinate expression of cytokeratin 8 and cytokeratin 17 immunohistochemical staining in cervical intraepithelial neoplasia and cervical squamous cell carcinoma: an immunohistochemical analysis and review of the literature

OBJECTIVE

Several Cytokeratin (CK) isoforms have been analyzed in cervical intraepithelial lesions. However, previously reported numbers of specimens have been too low to evaluate any correlation between CK and CIN.

METHODS

We examined the immunohistochemical staining of p16, CK8, and CK17 in 134 cervical tissues obtained by punch biopsy and graded as follows: CIN I (n=39), CIN II (n=31), CIN III (n=43), SCC (n=21).

RESULTS

p16 staining was identified in 74.4% of CIN I, 93.6% of CIN II, 97.7% of CIN III, and 100% of SCC cases. CK8 and CK17 staining were identified in 12.8% and 33.3% of CIN I, 22.6% and 58.1% of CIN II, 62.8% and 81.4% of CIN III, and 71.4% and 95.2% of SCC cases, respectively. Interestingly, positivity for CK8 and CK17 correlated with increasing lesion grade of the intraepithelial lesions and also correlated with p16 staining (p16, p=0.0008; CK8, p<0.0001, and CK17, p<0.0001), and a coordinate expression profile of CK8[+]/CK17[+] correlates with increasing CIN grade and carcinoma (likewise, a coordinate expression profile of CK8[-]/CK17[-] correlates with decreasing CIN grade and absence of carcinoma), but expression of just CK8 (CK8[+]/CK17[-]) or just CK17 (CK8[-]/CK17[+]) does not correlate with increasing CIN grade and carcinoma.

CONCLUSIONS

Results of the present study showed that p16, CK8, and CK17 immunostaining differed according to the degree of cervical intraepithelial lesions and SCC, and surprisingly, that staining was significantly correlated with increasing lesion grade of CIN and SCC.

Sudden death caused by fulminant bacterial infection: background and pathogenesis of Japanese adult cases

OBJECTIVE

To analyze a risk factor for the onset of fulminant bacterial infection.

PATIENTS AND METHODS

Nine unexpected acute death cases were clinicopathologically analysed. All cases represented the sudden onset of shock symptom, led to acute death within a few days, and later bacteremia was identified. Pathogens were Streptococcus pneumoniae (S. pneumoniae) (5 cases), group A beta Hemolytic Streptococcus pyogenes (S. pyogenes) (3 cases), and Vibrio vulnificus (V. vulnificus) (1 case).

RESULTS

Seven of the nine patients had underlying chronic illness. S. pneumoniae infection was associated with splenic dysfunction, and group A beta Hemolytic S. pyogenes and V. vulnificus infections were associated with alcoholic liver injury. Group A beta hemolytic S. pyogenes and V. vulnificus infections involved necrotizing fasciitis, and alcoholic liver cirrhosis was confirmed in two of the four patients.

CONCLUSION

Despite the different type of bacteria, the onset of fulminant bacterial infection depended upon depressed bacterial phagocytosis in the liver or spleen. Underlying chronic illnesses should be identified as a predisposing common risk factor. It is important to understand the relations between underlying chronic illness and the onset of fulminant infection.

Clinicopathological findings in fulminant-type pneumococcal infection: Report of three autopsy cases

Reported herein are three autopsy cases of fulminant-type pneumococcal sepsis with disseminated intravascular coagulation (DIC) resulting in death within a few days of onset of symptoms. Two of the three patients had previously had a splenectomy because of a hematological disorder. None of the patients had received pneumococcal vaccination. On post-mortem every organ had congestion as well as bleeding. Interestingly, severe inflammation of the alveoli was absent despite the sepsis. The cause of death was rapidly progressive pneumococcal sepsis leading to DIC and circulatory failure, which appeared to cause pulmonary congestion and hemorrhage without pneumonia. It is important to understand the pathogenesis of fulminant-type pneumococcal infection because it is life-threatening for compromised hosts.

Right pleural effusion in Fitz-Hugh-Curtis syndrome

Right pleural effusion was diagnosed in a 36-year-old woman with right upper quadrant pain and fever. Enhanced pelvic computed tomography performed because of irregular genital bleeding revealed the pelvic inflammatory disease. Upon further questioning, the patient confirmed that she had recently undergone therapy for Chlamydia trachomatis infection. Therefore she was given an injection of tetracycline because we suspected Fitz-Hugh-Curtis syndrome (FHCS), a pelvic inflammatory disease characterized by perihepatitis associated with chlamydial infection. A remarkable clinical response to antibiotics was noted. The right upper quadrant pain was due to perihepatitis, and the final diagnosis was FHCS. Right pleural effusion may be caused by inflammation of the diaphragm associated with perihepatitis. Once chlamydial infection reaches the subphrenic liver, conditions in the closed space between the liver and diaphragm due to inflammatory adhesion may be conductive to chlamydial proliferation. The possibility of FHCS should be considered in patients and carefully distinguished from other abdominal diseases.

Three cases of extranodal NK/T-cell lymphoma of the nasal type diagnosed by nasal brush cytology

Extranodal natural killer (NK)/T-cell lymphoma of the nasal type is a rare type of malignant lymphoma that is most common in Asian countries. Here we describe cytomorphologic, immunocytochemical, and molecular cytochemical features of three cases of NK/T-cell lymphoma of the nasal type diagnosed by nasal brush cytology. Cytomorphologic findings common among the three cases included the presence of several cell types, including nasal cavity epithelial cells, histiocytes, phagocytic histiocytes, and lymphoid cells, within a necrotic background. Suspected lymphoma cells were medium to large lymphoid cells possessing light blue and abundant cytoplasm. A characteristic feature of these cells was the presence of the tongue-like projections of cytoplasm from one or both sides of the cells. We believe these intriguing cytologic findings are indicators of NK/T-cell lymphoma of the nasal type. Azurophilic granules were observed in all cases, ranging from extremely fine granules to large granular lymphocyte (LGL)-like granules. Immunocytochemical and molecular cytochemical analyses showed staining for natural killer cell antigen CD56 as well as cytotoxic granule-associated proteins granzyme B7 (GrB7) and T-cell-restricted intercellular antigen-1 (TIA-1). EBV (Epstein-Barr virus) encoded small RNAs (EBER) positivity was shown by in situ hybridization, and no rearrangement of the TCRgamma gene was observed. Comparison between cytobrush and cotton swab methodology showed that cytobrush resulted in more cell-rich specimens than did cotton swabs, suggesting that nasal brush cytology with cytobrush is most useful in the diagnosis of NK/T-cell lymphoma of the nasal type.

Gadolinium-Enhanced Fat-Suppressed T1-Weighted Imaging for Staging Ureteral Carcinoma: Correlation with Histopathology

OBJECTIVE

The purpose of this study was to retrospectively compare contrast-enhanced fat-suppressed T1-weighted images with histopathologic findings in ureteral carcinoma to develop accurate preoperative MR criteria for T staging.

CONCLUSION

Contrast-enhanced fat-suppressed T1-weighted images can be used to distinguish thickened noncarcinomatous ureteral walls, which occur due to the proliferation of fibrous tissue, from ureteral carcinoma because fibrous tissue enhances more intensely on MRI than ureteral carcinoma. We also observed that when ureteral carcinomas had invaded periureteral fat tissue, a disruption or fragmentation of the intensely enhancing ureteral wall was seen. Using the MR criteria for T staging that we developed on the basis of these findings, we were able to accurately determine whether a carcinoma had invaded periureteral fat tissue in all of our patients.

Novel BLIMP1/PRDM1 gene mutations in B-cell lymphoma

B lymphocyte-induced maturation protein 1 (BLIMP1)/PR domain containing 1 with zinc finger domain (PRDM1) is a transcriptional repressor with a SET domain and Kruppel-type zinc fingers. BLIMP1/PRDM1 is expressed in a subset of germinal center B cells and in all plasma cells, and it is required for terminal B-cell differentiation. Mutations of the BLIMP1 gene have been reported in patients with diffuse large B-cell lymphoma. Here, we describe novel mutations in the BLIMP1 gene in 2 of 15 (13%) cases of B-cell lymphoma (two cases of primary effusion lymphoma and 13 cases of diffuse large B-cell lymphoma). A tandem 10-base pair duplication (5'-GCTGAGTTTG-3') was found in exon 2 of the BLIMP1 gene in primary effusion B-cell lymphoma. We also found in diffuse large B-cell lymphoma a single base substitution in exon 6 (1747C-->T) that results in a somatic nonsense mutation (Q583X). These findings indicate that mutational analysis of the BLIMP1 gene may be useful for characterizing the molecular basis of B-cell lymphoma.

Combined small cell carcinoma with pulmonary blastoma and adenocarcinoma: Case report and clonality analysis

We describe a rare tumor occurring in the left pulmonary lobe of a 71-year-old Japanese man. The tumor, which was resected by left lower lobectomy, measured 65 x 50 x 50 mm. Histologic examination revealed papillary adenocarcinoma in small cell carcinoma, and chondrosarcoma. Also, the blastemal cells were located between the small cell carcinoma and the chondrosarcoma, and intermingled with both components. In blastemal cells, some glands resembled a well-differentiated fetal adenocarcinoma. The tumor was diagnosed as combined small cell carcinoma with pulmonary blastoma and papillary adenocarcinoma according to the 2004 WHO classification. Immunohistochemically, the small cell carcinoma expressed TTF-1, pancytokeratin, CD56, synaptophysin, and S100 protein, while blastemal cells expressed vimentin, desmin, smooth muscle actin, CD56, and S100 protein. To investigate whether the tumor was clonal or not, p53 gene mutation of each tumor component was analyzed by laser-captured microdissection, polymerase chain reaction-single-strand conformation polymorphism and direct sequencing. Despite the histologic complexity, all components showed the same mutation at exon5 of the p53 gene. These results indicate that the tumor was clonal and arose from a relatively primitive cell, and that p53 mutation occurred before histologic metamorphosis or differentiation.

[Thymidylate synthase and dihydropyrimidine dehydrogenase expression and histological effects of preoperative UFT in gastric cancer patients]

During DNA synthesis in tumors, fluoropyrimidine anticancer agents target thymidylate synthase (TS) that catalyze the synthesis of dTMP from dUMP and are metabolized by dihydropyrimidine dehydrogenase (DPD). We administered UFT to patients with gastric cancer preoperatively to prevent cancers from advancing while they await surgery or down staging.

PATIENTS AND METHODS

We administered UFT to 24 gastric cancer patients at 360 mg/m(2)/day for longer than 3 weeks as a preoperative chemotherapy. TS and DPD expression in the tumor were measured by immunohistochemistry staining before and after (during surgery) chemotherapy and compared with the results of histological assessment.

RESULTS

TS and DPD expression decreased significantly after UFT administration (p<0.05). Histological assessment showed Grade 1 b or 2 in 11 of 24 patients (46%). Eight of 15 patients with high DPD (53.3%) exhibited Grade 1 b or 2.

CONCLUSIONS

Histological assessment revealed the efficacy of UFT, through a DPD-inhibitory fluoropyrimidine (DIF) effect, in patients with high DPD. This suggests that preoperative administration of UFT can be a useful clinical measure.

Novel NF1 gene mutation in a Japanese patient with neurofibromatosis type 1 and a gastrointestinal stromal tumor

Many mutations of the NF1 gene have been reported in patients with neurofibromatosis type 1 (NF1); however, there have been no documented NF1 gene mutations in Japanese NF1 patients. In the present study, we used the polymerase chain reaction (PCR) and DNA sequencing analysis to characterize the NF1 gene in a 53-year-old Japanese patient with NF1 who suffered from neurofibroma, pheochromocytoma, and gastrointestinal stromal tumor (GIST). Direct sequence analyses revealed a single base substitution in the splicing donor site of intron 6 (IVS6 888+1, G --> A) in one NF1 allele, resulting in an altered splice site (ss) in the mutated allele. Splicing at the cryptic 5' ss in the mutated allele generated mRNA with an insertion of 60 nucleotides. In addition, we screened for mutations in exons 9, 11, 13, and 17 of the c-kit gene in GIST and the succinate dehydrogenase subunit D (SDHD) gene in the pheochromocytoma, but we did not detect any somatic mutations. We report here the first case of an NF1 patient with four neoplasms: neurofibroma, pheochromocytoma, astrocytoma and GIST. Our results suggest that the molecular pathogenesis of GISTs in NF1 patients is different from that in non-NF1 patients.

A novel multicolor immunofluorescence method using heat treatment

We describe a novel method for immunofluorescent detection of multiple antigens in a single paraffin-embedded tissue section. We hypothesized that if fluorescent dyes are resistant to heat treatment, then thermal inactivation of immunoglobulins during antigen detection procedures might make it possible to use multicolor immunofluorescence detection even if the primary antibodies are from the same species. We found that several fluorescent dyes, including fluorescein isothiocyanate (FITC), Cy3 and Cy5, were resistant to heating at 90 degrees Celsius for 15 min, whereas the antigenicities of the primary antibodies were lost completely. This novel method, which uses heat treatment between staining steps, has great advantages for multicolor immunofluorescence because unlabeled primary antibodies from the same species can be used. Therefore, by using this method not only 3 unlabeled mouse monoclonal antibodies but also 3 unlabeled rabbit antisera can be used as primary antibodies for multicolor immunofluorescence.

Expression of CD10 and Cytokeratins in Ovarian and Renal Clear Cell Carcinoma

A solid pattern of tumor cells with a clear cytoplasm is common to both ovarian clear cell carcinoma (OvCCC) and renal clear cell carcinoma (RCCC). This study examined the possible differential expression of CD10 and cytokeratins (CK7, CK20, 34betaE12, and CAM5.2) between these two types. An immunohistochemical technique using peroxidase-labeled amino acid polymers was used to test formalin-fixed and paraffin-embedded tissues. In OvCCC, 6 of 29 cases were positive for CD10, and all cases had expression of CK7, 34betaE12, and CAM5.2. In contrast, all 24 RCCC cases had CD10 and CAM5.2 immunoreactivity, but none had any staining for 34betaE12. CK7 was only expressed in nine cases. No CK20 positivity was observed in any sample from either tumor type. Localization of CD10 expression was different in OvCCC versus RCCC. Although positive staining for 34betaE12 strongly suggests OvCCC, sometimes only a few cells may be stained. Therefore, 34betaE12-negative biopsies also should be evaluated for CD10 and CK7 immunoreactivity to enable histologic and cytologic differential diagnosis.

A c-KIT codon 816 mutation, D816H, in the testicular germ cell tumor: case report of a Japanese patient with bilateral testicular seminomas

Mutations of the c-KIT gene have been reported not only in gastrointestinal stromal tumors and mast cell tumors, but also in testicular germ cell tumors (TGCTs). In the present study we employed polymerase chain reaction and DNA sequencing analysis to characterize the c-KIT gene in a 29-year-old Japanese patient with bilateral testicular seminomas. Direct sequence analyses revealed a single base substitution in exon 17 in one c-KIT allele, resulting in an amino acid substitution of D816H in this mutated allele. This mutation was found in the left, but not in the right, testicular seminoma. This is the first description of a c-KIT gene mutation in a Japanese patient with bilateral TGCT. The mutational analysis of the c-KIT gene seems to provide crucial information for managing TGCT patients not only in Europe but also in Japan.

Sequential progression and intraductal spread of invasive ductal adenocarcinoma of the pancreas arising from around the main pancreatic duct

A 76-year-old woman was admitted to our hospital after increased transaminase, hepato-biliary enzyme levels, and tumor markers were found. Abdominal contrast computed tomography revealed a mass (20 x 18 mm) in the uncus of the pancreas. Magnetic resonance cholangiopancreatography showed an abrupt narrowing with the dilatation of the peripheral main pancreatic duct (MPD) in the pancreatic head. Endoscopic retrograde cholangiopancreatography showed only dilatation of the lower bile duct; insertion of the cannula was not seen because the MPD was obstructed. The patient underwent a Whipple-pancreatoduodenectomy. Histopathological and immunohistochemical examinations led to a diagnosis of sequential progression and intraductal spread of invasive ductal adenocarcinoma of the pancreas arising from around the main pancreaticduct. Interestingly, the intraductal spread was approximately 20 mm to the point where the carcinoma began to infiltrate. To the best of our knowledge, there have been no other reported cases of such broad intraductal spread, indicating that noninvasive lesions that replace the normal epithelia can be broader than those reported previously.

Fine needle aspiration cytology of primary proximal-type epithelioid sarcoma of the perineum: a case report

BACKGROUND

Epithelioid sarcoma is a malignant soft tissue tumor of unknown histogenesis. We describe the cytologic findings in a case of primary proximal-type epithelioid sarcoma of the perineum and results of an immunofluorescence analysis of rhabdoid cells from this tumor. To the best of our knowledge, the 3-color immunofluorescence features of proximal-type epithelioid sarcoma have never before been reported.

CASE

An 8-cm-diameter mass with a 2.5-cm ulcer was found in the perineum of a 36-year-old man. After excision of the tumor, histopathologic examination of the resected specimen suggested a diagnosis of proximal-type epithelioid sarcoma. Fine needle aspiration cytology showed numerous rhabdoid cells with globular intracytoplasmic inclusions. A few isolated cells and polygonal cells were also observed in the smears. Three-color immunofluorescence analysis indicated that the intracytoplasmic inclusions in the rhabdoid cells were positive for cytokeratin, vimentin and CD34. The cytoplasmic staining pattern differed between rhabdoid and epithelioid sarcoma cells.

CONCLUSION

Immunofluorescent staining of rhabdoid cells from a primary perineal proximal-type epithelioid sarcoma revealed an uneven distribution of cytokeratin in intracytoplasmic inclusions, with the highest concentration at the periphery of the inclusions.

Effusion cytodiagnosis of carcinosarcoma derived from the female genital tract: immunohistochemical features of MMP-7 and Ki-67 and immunofluorescence double staining analyses of eight cases

OBJECTIVE

Expression of Matrix metalloproteinase 7 (MMP-7) and Ki-67 by carcinoma components (CCs) and sarcoma components (SCs) in carcinosarcoma of the female reproductive organs has been investigated by conventional methods, but analysis with immunohistochemical staining of multiple antigens has not been reported. We report the profiles of expression of MMP-7 and Ki-67 in carcinosarcoma determined with immunohistochemical staining techniques.

METHODS

We used antibodies against epithelial antigen (EA), epithelial membrane antigen (EMA), and vimentin for immunofluorescence double staining of ascitic fluid in eight cases of carcinosarcoma of female reproductive organs. We also used immunohistochemical triple staining to compare MMP-7 and Ki-67 expression between CCs and SCs in the primary site of carcinosarcoma.

RESULTS

Immunofluorescence analysis revealed that all neoplastic cells in the ascitic fluid were positive for EA or EMA, indicating that these cells were CCs. Immunohistochemical analyses of the primary organ of carcinosarcoma revealed that MMP-7 was expressed on CCs in four of eight cases of carcinosarcoma, whereas MMP-7 was not expressed on SCs. The average Ki-67 labeling index (LI) in CCs and SCs was 51.8% and 28.6%, respectively. The difference in Ki-67 LI between CCs and SCs was statistically significant (t test for paired samples, P = 0.0173).

CONCLUSIONS

This is the first study to examine carcinosarcoma of the female reproductive organ by immunohistochemical staining for multiple antigens, which allows analysis of mixed tumor elements. In addition, we found that expression of MMP-7 and the average Ki-67 LI differ between CCs and SCs in carcinosarcoma. The predominance of CCs as the malignant cells in the ascitic fluid may be due to cytological differences between CCs and SCs of carcinosarcoma.

Renal oncocytosis

Renal oncocytosis is a rare disorder in which numerous oncocytic nodules develop in the kidney. An additional case is reported here. The patient was a 51-year-old woman who had received hemodialysis for 27 years. Nineteen years previously she had developed a tumorous lesion in the right kidney, which had been diagnosed as oncocytoma with laparotomic biopsy. Recently the kidney was removed because of enlargement of the tumor. The renal parenchyma was entirely replaced with numerous brownish nodules. Histologically, the nodules were composed of nests of uniform oncocytic cells. Ultrastructurally, the oncocytic cells contained numerous mitochondria. Immunohistochemical features of the nodules were identical to those of sporadic oncocytomas, that is, immunophenotypes similar to the distal nephron and reactivity with antimitochondrial antigen. Based on these findings, the lesion was diagnosed as renal oncocytosis. It was not possible to determine whether the larger nodules should be diagnosed as oncocytoma or a part of oncocytosis. Additionally, the germ line mutation of the Birt-Hogg-Dubé (BHD) syndrome gene was examined using the genomic DNA obtained from the peripheral lymphocytes, which failed to show any gene alteration. Despite the rare occurrence pathologists and urologists should be aware of renal oncocytosis, as a precursor lesion of renal oncocytoma and chromophobe renal cell carcinoma.

Intraductal tubular neoplasms of the pancreas: histogenesis and differentiation

OBJECTIVES

Intraductal neoplasms of the pancreas are generally referred to as intraductal papillary mucin-producing neoplasms (IPMNs), according to the WHO classification system. Herein, we report that morphologic and immunohistochemical features of intraductal tubular carcinoma (ITC) are quite different from those of intraductal papillary mucinous carcinoma (IPMC).

METHODS

We analyzed histogenesis and differentiation of ITC by light microscopy and immunohistochemistry.

RESULTS

Histologically, ITC was characterized as an intraductal nodular appearances with a monotonous tubular growth pattern without papillary projection. ITC showed de novo-like appearance without sequential progression usually observed in IPMC, suggesting that ITC is a homogeneous neoplasm. Cuboidal tumor cells in ITC resembled normal pancreatic duct epithelia, and the characteristic growth pattern of ITC replaced that of normal pancreatic duct epithelium. Immunohistochemically, ITC cells were positive for MUC-1 on the apical side of the cell membrane. In contrast to ITC cells, IPMC cells were negative for MUC-1, and ductal adenocarcinoma cells were strongly positive for MUC-1, as was the stroma around the cancer. The immunohistochemical staining pattern of DUPAN-2 resembled that of MUC-1. Interestingly, localization of MUC-1 and DUPAN-2 staining in ITC cells was similar to that in normal pancreatic ductules. ITC cells were negative for MUC-2 and MUC-5AC. In contrast, most IPMC cells were positive for MUC-2 and MUC-5AC.

CONCLUSION

Based on our histologic and immunohistochemical findings, the intraductal pancreatic neoplasm (IPN) can be classified into 2 groups: IPN with gastrointestinal differentiation and IPN with pancreatic duct differentiation. Our present data indicated that ITC cells may arise directly from duct epithelia without progression and possessed pancreatic duct differentiation. On the basis of our data, we suggest that classification of pancreatic neoplasms in the WHO and The Armed Forces Institute of Pathology (AFIP) systems should be reconsidered.

Proximal-type epithelioid sarcoma in a 36-year-old man: closer immunoelectron-microscopic resemblance of the tumor cells to epithelial cells than to mesenchymal cells

Proximal-type epithelioid sarcoma (PES) is a rare neoplasm. We report a case of PES that arose in the perineal subcutis of a 36-year-old Japanese man who died within 4 months of the first clinical sign, probably due to massive pulmonary metastases. In the present study, we analyzed the tumor obtained at surgery, immunohistochemically, immunoelectron-microscopically and genetically. Although the tumor cells in the patient expressed both cytokeratin and vimentin immunohistochemically, they showed epithelial characteristics immunoelectron-microscopically because they had tonofilaments constructed of cytokeratin, not vimentin. In addition, the cytokeratins expressed on the tumor were glandular-type keratins. These findings indicate that PES may be a form of carcinoma in soft tissue. To ascertain the possible origin of the tumor, we compared the tumor immunohistochemically with fetal tissues. Although notochord and fetal peritoneal mesothelium were similar to the tumor antigenically, we could not confirm the specific origin of the tumor. Furthermore, the p53-WAF1 pathway did not contribute to tumorigenesis in the patient because the tumor had no mutation in exons 5-8 of the p53 gene and was immunohistochemically positive for WAF1.

Cytomorphologic features of immature ovarian teratoma in peritoneal effusion: A case report

We describe unusual cytologic features of the peritoneal fluid in a patient with immature ovarian teratoma. Immature embryonal and neuroectodermal components of such tumors are rarely observed in the ascites; to our knowledge, there have been only three reports of cytologic findings of immature teratoma cells in the ascites. Our patient was a 26-yr-old woman who presented with a huge pelvic mass. A grade 3 immature right ovarian teratoma was diagnosed pathologically. Cytologic examination of the ascitic fluid revealed a variety of neoplastic cells, including immature neuroepithelial cells forming rosette-like structures, keratinized squamous cells, squamoid metaplastic cells, and immature glial-appearing cells. Immunohistochemical analysis revealed that immature gastrointestinal elements and yolk sac elements were positive for alpha-fetoprotein. This is the first description of the cytologic features of non-neuroepithelial elements in the ascitic fluid in a patient with immature ovarian teratoma.