Development of demyelinating lesions in progressive multifocal leukoencephalopathy (PML): Comparison of magnetic resonance images and neuropathology of post-mortem brain.

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disorder caused by opportunistic infection of JC polyomavirus (JCV). Today, increased attention has been focused on PML development in multiple sclerosis (MS) patients under disease-modifying therapies (DMT). Although in the acquired immunodeficiency syndrome (AIDS) era, PML was thought to be a rapidly progressive disease with poor prognosis, drug-associated PML is relatively slow in progress, and a favorable outcome may be expected with early diagnosis. However, early PML diagnosis on magnetic resonance imaging (MRI) is frequently difficult, and JCV DNA copy number in cerebrospinal fluid (CSF) is usually low. To facilitate early PML diagnosis on MRI, the pre-mortem images were compared with neuropathology of the post-mortem brain, and underlying pathology corresponding to the MRI findings was evaluated. As a result, PML lesions of the autopsied brain were divided into three parts, based on the disease extension patterns: (A) Progressive white matter lesion in the right frontoparietal lobe including the precentral gyrus. Huge demyelinated lesions were formed with fusions of numerous small lesions. (B) Central lesion including deep gray matters, such as the putamen and thalamus. The left thalamic lesion was contiguous with the pontine tegmentum. (C) Infratentorial lesion of brainstem and cerebellum. Demyelination in the pontine basilar region and in cerebellar white matter was contiguous via middle cerebellar peduncles (MCPs). In addition, (D) satellite lesions were scattered all over the brain. These observations indicate that PML lesions likely evolve with three steps in a tract-dependent manner: (1) initiation; (2) extension/expansion of demyelinating lesions; and (3) fusion. Understanding of the PML disease evolution patterns would enable confident early diagnosis on MRI, which is essential for favorable prognosis with good functional outcome.

[Mixed adenoneuroendocrine carcinoma with multiple liver metastases successfully treated by cetuximab/CPT-11 chemotherapy followed by curative resection - a case report].

A 73-year-old man underwent laparoscopy-assisted partial resection of the rectum to treat rectal cancer diagnosed in September 2011 at a previous hospital. Lymph node dissection was not performed and the vertical margin was positive. When multiple liver tumors were detected 10 months later, the patient was referred to our hospital. A computed tomography (CT) scan revealed local recurrence of the rectal cancer, lymph node metastasis, and 9 liver metastases, which had a maximum diameter of 10 cm, and where curative resection would have been difficult. The rectal cancer expressed epidermal growth factor receptor (EGFR) and wild type K-ras gene, and we initiated cetuximab/irinotecan (CPT-11) chemotherapy. After 2 courses of chemotherapy, the liver tumors had markedly decreased in size and anterior resection of the rectum with regional lymph node dissection was performed. The pathological diagnosis of the rectal tumor was mixed adenoneuroendocrine carcinoma ( MANEC). Extended right hepatectomy was performed four months later. The liver tumors were also diagnosed as metastases of MANEC of the rectum. The therapeutic efficacy of chemotherapy was assessed as Grade 1b. The patient is alive without recurrence 34 months since the initial rectal surgery and 15 months after the liver resection. Thus, an anti-EGFR antibody agent might be effective against MANEC of the colon and rectum.

Molecular analysis of multifocal prostate cancer by comparative genomic hybridization.

BACKGROUND: Prostate cancer is often multifocal and shows histological heterogeneity among different tumor foci within the same prostate. We analyzed the origin and molecular basis of multifocal prostate cancer and genomic alterations associated with tumor progression. METHODS: We examined 45 multifocal prostate cancer foci from 22 radical prostatectomy specimens by comparative genomic hybridization (CGH). Laser capture microdissection (LCM) was used to gather cancer cells from frozen prostate specimens. RESULTS: Frequent chromosomal alternations were losses of 2q21-24 (22.2%), 6q14-22 (60.0%), 8p12-22 (35.6%), 13q14-31 (44.4%) and 16q13-24 (24.4%) and gains of 8q21.3-24.3 (37.8%) and 7q21-33 (20.0%). Frequency of losses of 8p12-22 and 16q13-24 and gains of 8q21.3-24.3 were significantly higher in tumors with high Gleason score (GS) than in those with low GS (P < 0.01, P < 0.05, and P < 0.01, respectively). Tumors with losses of 8p12-22 or 13q14-31 displayed larger volume than those without such losses (P < 0.05 and P < 0.01, respectively). In comparison between different tumor foci within the same prostate, chromosomal alterations did not show completely the same pattern between any tumor foci, except for one case in which two of the three foci displayed no chromosomal abnormalities. More malignant tumors (high GS or extracapsular invasion) displayed significantly higher frequency of losses of 8p12-22 (P < 0.05). CONCLUSIONS: These results suggest that tumor foci within the same prostate represent independent tumors with differing clonal origin and that loss of 8p12-22 represents an important determinant of prostate cancer progression.

The expression of NeuroD and mASH1 in the gastroenteropancreatic neuroendocrine tumors.

Gastroenteropancreatic neuroendocrine tumors are uncommon and their tumor biology has not been well elucidated to date. Currently the WHO classification is widely used for the diagnosis and distinction of this tumor entity, which is sometimes cumbersome. Although neuroendocrine tumor markers do exist (ie chromograninA, synaptopyhsin, etc), sensitive and specific markers that accurately predict tumor growth and tumor behavior are still absent. In the present study, we assessed the expression of transcription factors (NeuroD and mASH1) essential for the normal fetal neuronal development in 33 gastroenteropancreatic neuroendocrine tumor patients (12 well-differentiated neuroendocrine tumors, 7 well-differentiated neuroendocrine carcinomas, and 14 poorly differentiated neuroendocrine carcinomas). NeuroD was less expressed in poorly differentiated neuroendocrine carcinoma (small-cell type) compared to well-differentiated neuroendocrine tumor (carcinoid) by reverse transcription-polymerase chain reaction. Immunohistochemical staining revealed that mASH1 was highly (sensitivity of 71%) and specifically (specificity of 95%) expressed in poorly differentiated neuroendocrine carcinoma. High NeuroD expression was seen in all well-differentiated neuroendocrine carcinoma and tumor (carcinoid) patients. Low NeuroD expression was seen in 36% (5 of 14) of poorly differentiated neuroendocrine carcinoma patients, which was associated with significant shorter overall survival. The expression pattern of these transcription factors may represent the biological and pathophysiological difference of gastroenteropancreatic neuroendocrine tumors and may become a new marker for the distinction of gastroenteropancreatic neuroendocrine tumors.

The expression of hepatocyte nuclear factor-4alpha, a developmental regulator of visceral endoderm, correlates with the intestinal phenotype of gastric adenocarcinomas.

AIMS: Hepatocyte nuclear factor (HNF)-4alpha is a developmental regulator of the visceral endoderm, which is expressed in the embryonic gut and later in the adult intestine and colon. However, adult gastric mucosa does not express HNF-4alpha. We investigated the possible involvement of HNF-4alpha in intestinal metaplasia and the intestinalisation of gastric adenocarcinomas. METHODS: Thirty-five cases of adenocarcinomas and 46 cases of adjacent non-neoplastic mucosa with (22 lesions) or without (24 lesions) intestinal metaplasia were immunostained for HNF-4alpha. The gastric or the intestinal phenotype was also examined using immunohistochemistry for MUC5AC, MUC2, CD10, and gastric-type mucin (GTM). Adenocarcinomas were classified into the gastric type (G-type, 42.9%), the mixed gastric and intestinal type (GI-type, 31.4%), and the intestinal type (I-type, 25.7%). RESULTS: The HNF-4alpha expression was exclusively seen in glandular cells with intestinal metaplasia, which was correlated with MUC2 expression (p<0.05) and inversely correlated with MUC5AC expression (p<0.05). All adenocarcinomas more or less expressed HNF-4alpha, with an intense expression being seen in the I-type (p<0.01) and in well-differentiated adenocarcinomas (p<0.03). CONCLUSIONS: HNF-4alpha expression is associated with the intestinal phenotype of non-neoplastic and neoplastic gastric glandular cells, suggesting a possible involvement in the establishment and/or maintenance of the intestinal phenotype of the gastric mucosa and adenocarcinomas.

Rapid diagnosis of micrometastasis of gastric cancer using reverse transcription loop-mediated isothermal amplification.

Methods to detect metastases in biopsy specimens with certain rapidity and accuracy are essential to performing tailor-made surgeries for solid malignancies. Reverse transcription loop-mediated isothermal amplification (RT-LAMP) reaction is a novel technique for detecting mRNA expression of target sequences with high sensitivity and rapidity, even from crude samples without RNA purification. Applicability to detect lymph node (LN) micrometastasis of gastric cancer was tested. Total of 26 LNs were retrieved from 10 patients with primary gastric cancer. Each LN was serially sectioned, and every set of three serial sections were tested for routine histopathological (H&E) and immunohistochemical examination with anti-cytokeratin antibodies (IHC), and RT-LAMP analysis targeted cytokeratin 19 mRNA. Results from H&E/IHC and RT-LAMP analysis were compared in each set of sections. All the sections of those containing metastatic lesions equivalent to a volume of overt metastasis (maximum diameter>2 mm), 90% of those containing micrometastasis (between 2 and 0.2 mm) and 83% of those containing isolated tumor cells (<0.2 mm) were detectable using this procedure. Total analysis from lysates of clinical specimens required<75 min. This new technique is suggested to be an alternative to rapid diagnosis of micrometastasis based on conventional histopathological analysis.

Postoperative recurrence of an IPMN of the pancreas with a fistula to the stomach.

We report on a case of a 74 year old man who was diagnosed with a recurrence of non-invasive carcinoma of intraductal papillary mucinous neoplasm (non-invasive IPMN) by postoperative gastroscopy (GS). A pylorus preserving pancreatico duodenectomy for IPMN in the pancreatic head was performed. A histopathological study revealed non-invasive adenocarcinoma. At first, the local recurrence of the tumor around the superior mesenteric artery circumference was diagnosed and disappeared with gemcitabine. Later, the GS showed the elevated lesion with mucin hypersecretion in the remnant stomach. The lesion had a central dip and a fistula common to the pancreas was confirmed on fisterography. We diagnosed a recurrence of IPMN and administered chemotherapy again. However, he died of his original illness. There are no reports of postoperative recurrence of IPMN checked by GS. It should be remembered that the elevated lesion of the remnant stomach is considered as one of the recurrent patterns of IPMN.

Expression of an activated mammalian target of rapamycin (mTOR) in gastroenteropancreatic neuroendocrine tumors.

AIMS: Gastroenteropancreatic neuroendocrine tumors are rare, and the current WHO classification divides this tumor entity into well-differentiated (neuro)endocrine tumors, well-differentiated (neuro)endocrine carcinomas, and poorly differentiated (neuro)endocrine carcinomas. Poorly differentiated (neuro)endocrine carcinoma is extremely aggressive, and no appropriate therapeutic approach has been established. The mammalian target of rapamycin (mTOR), an important regulator of cell proliferation and protein translation, is activated in various malignancies. Recent phase II trial has revealed the efficacy of mTOR inhibitor (RAD001; everolimus) against low-to-intermediate grade neuroendocrine tumors. However, the beneficial role of mTOR inhibitor against poorly neuroendocrine carcinoma remains uncertain. The purpose of the present study was to determine the activation of mTOR in gastropancreatic neuroendocrine tumors, especially in poorly differentiated neuroendocrine carcinomas. METHODS: Expression of p-mTOR(Ser2448) was assessed by immunohistochemistry in 20 gastropancreatic neuroendocrine tumors (seven well-differentiated neuroendocrine tumors, four well-differentiated neuroendocrine carcinomas, and nine poorly differentiated neuroendocrine carcinomas). Double immunohistochemistry was performed with p-Akt for patients with high p-mTOR expression. RESULTS: Expression of mTOR was seen in 9 (45%) of 20 gastroenteropancreatic neuroendocrine tumors. High expression of p-mTOR was seen in 6 (67%) of 9 poorly differentiated neuroendocrine carcinomas which was higher than the expression rate of well-differentiated neuroendocrine tumors and carcinomas, 3 (27%) of 11. All large cell neuroendocrine carcinomas showed high p-mTOR expression. Some tumor cells showed positive staining for p-mTOR co-expressed p-Akt. CONCLUSIONS: High expression rate of p-mTOR in poorly differentiated neuroendocrine carcinomas (large-cell type) may suggest the potential role of mTOR inhibitors as effective therapeutic agents for this highly malignant disease.

Useful DNA typing using AmpFlSTR Identifiler Kit for formaldehyde-fixed paraffin-embedded (FFPE) tissues in early gastric cancer patient with lymph node metastasis.

After distal gastrectomy in a patient with early gastric cancer, 27 regional lymph nodes around the stomach were evaluated for the existence of metastasis. There was a 0IIa+IIc type tumor 2.0 x1.5 cm in size in the gastric angle of the lesser curvature according to the Japanese Classification of Gastric Carcinoma (JCGC). Histologically, the lesion extended no deeper than the muscularis mucosae. The cancer stage was so early that no metastasis was expected to occur but a lymph node with metastasis was found in one lymph node along the common anterior hepatic artery (station No.8a). This histological type was a little different from that of a primary tumor. The doctor began to suspect that the lymph node with metastasis might have been from another patient by mistake. Therefore, DNA typing using the AmpFlSTR Identifiler kit was performed in formaldehyde-fixed paraffin-embedded (FFPE) tissues: 2 parts of gastric mucosa without cancer, one part of gastric mucosa with cancer, 4 lymph nodes without metastasis, and the lymph node station No.8a with metastasis. STR typing was successful in 6~14 STR loci and amelogenin gene, and the detected STR type was the same in all samples. Compared with the STR type using DNA from the patient's blood, the lymph node station No.8a was from the same patient. The lymph node with metastasis turned out to be not from another patient. Therefore, we suggest that DNA typing using the AmpFlSTR Identifiler Kit for FFPE samples is useful in such clinical cases.

Rapid detection of metastasis of gastric cancer using reverse transcription loop-mediated isothermal amplification.

Tailor-made surgeries for patients with solid malignancies have been under consideration on the basis of the development of new approaches for minor metastatic foci of malignant tumors. Accurate and reliable methods to detect metastases in biopsy specimens with certain rapidity are essential for the performance of these surgeries. The aim of this study was to develop a rapid and practical method to detect metastasis in specimens from patients with gastric carcinoma with the use of reverse transcription loop-mediated isothermal amplification (RT-LAMP) reaction, a novel technique for detecting mRNA expressions of targeted sequences with high sensitivity, specificity and rapidity under isothermal conditions. RT-LAMP primers to detect cytokeratin19 (CK19) mRNA were generated and 92 lymph nodes (LNs) obtained from 9 patients with gastric cancer were tested for tumor metastases with this technique. Among 92 LNs, 15 were metastasis-positive by routine histopathological examination. RT-LAMP reaction detected CK19 expression in all of the pathologically positive LNs and in 16 of 77 negative LNs. Nested RT-PCR assay for CK19 expression was also performed on 2 of the 9 cases including 32 LNs. The agreement rate of CK19 expression detection by RT-LAMP and RT-PCR analysis was 31/32 (97%). The RT-LAMP technique showed similar sensitivity to detect metastases as nested RT-PCR assay, with a rapidity comparable to that of intraoperative histopathological examination with frozen sectioning and hematoxylin and eosin staining. This method is expected to play an essential role in the performance of tailor-made surgeries in the near future.

Distinction of pulmonary large cell neuroendocrine carcinoma from small cell lung carcinoma: a morphological, immunohistochemical, and molecular analysis.

The distinction between pulmonary large cell neuroendocrine carcinoma and small cell carcinoma is difficult in some cases. Some propose that these carcinomas should be classified as one high-grade neuroendocrine carcinoma. We examined biological features of small cell carcinoma (n=23), large cell neuroendocrine carcinoma (n=17), and classic large cell carcinoma (n=12). The average ratio of nuclear diameter of the tumor cells to that of lymphocytes for small cell carcinoma was smaller than that for large cell neuroendocrine carcinoma (P<0.0001). The frequencies of the expressions of CD56, mASH1, TTF-1, and p16 were higher and that of NeuroD was lower in small cell carcinoma than in large cell neuroendocrine carcinoma. The frequency of loss of heterozygosity at 3p was higher in high-grade neuroendocrine carcinomas than in classic large cell carcinoma (P=0.0002). Allelic losses at D5S422 (5q33) were more frequent in small cell carcinoma than in large cell neuroendocrine carcinoma (P=0.0091). Mean fractional regional loss indices of the tumors were 0.38, 0.65, and 0.72 for patients with classic large cell carcinoma, large cell neuroendocrine carcinoma, and small cell carcinoma, respectively (P=0.0003). Five-year overall survivals of patients with classic large cell carcinoma, large cell neuroendocrine carcinoma and small cell carcinoma in stage I were 67, 73, 60%, respectively. Patients with NeuroD expression had better survivals, and those with p63 expression had poorer survivals in large cell neuroendocrine carcinoma. Patients with TTF-1 expression had poorer survivals in small cell carcinoma. Our data suggest that large cell neuroendocrine carcinoma and small cell carcinoma are different morphologically, phenotypically, and genetically, although there are some overlapping features. Although further studies are needed to analyze the biological behavior of high-grade neuroendocrine carcinomas including sensitivity to chemotherapy, the pathological distinction of large cell neuroendocrine carcinoma from small cell carcinoma may be necessary to treat the patients with neuroendocrine tumors.

Metastatic germ cell tumor of the lung masquerading as primary rhabdomyosarcoma.

Two years after testicular resection was carried out in a 40-year-old man that revealed mixed germ cell tumor of more than one histological type (seminoma, embryonal cell carcinoma, and yolk sac tumor), he presented with an asymptomatic pulmonary nodule in his left lower lobe. Video-assisted thoracoscopic partial resection of the tumor revealed a 24 x 20 mm teratoma with somatic-type malignancy in which pleomorphic rhabdomyosarcoma was a major element. One year later, asymptomatic tumor recurrence occurred at both edges of the stapler line as 22 x 20 mm and 10 x 5 mm nodules composed only of pleomorphic rhabdomyosarcoma. Throughout the course there was no abdominal lymph node swelling detected by computed tomography (CT) and tumor markers were normal. Adjuvant chemotherapy was started after the tumor recurrence. Currently, the patient is still undergoing chemotherapy 5 months after the tumor recurrence. In conclusion, despite the fact that primary pulmonary rhabdromyosarcoma is a rare neoplasm, metastatic pulmonary germ cell tumor with somatic-type malignancy showing predominantly rhabdomyosarcomatous differentiation should be considered in the differential diagnosis of such lesions of the lung.

Pseudoinvasion of the colorectal polypoid tumors: serial section study of problematic cases.

Ten cases of endoscopically removed colorectal polypoid tumors exhibiting lobular growth patterns in the submucosa without prominent desmoplastic changes in the interstitium were investigated using serial sections, and four cases were confirmed to be pseudoinvasion. The growth pattern of these four cases (pseudoinvasive tumors) was morphologically compared with the other six tumors (microinvasive tumors) in which obviously infiltrating foci were seen in minimal ranges. In the pseudoinvasive tumors, intramucosal tumor tissue spread into the submucosa through the narrow gap of the muscularis mucosae and formed a lobulated nodule larger than the gap of the muscularis mucosae. This suggested that squeezing of the herniated tumor tissue by muscularis mucosae at the gap was crucial to forming a typical feature of pseudoinvasion. The maximum diameters of the gap of the muscularis mucosae (G) and the submucosal tumor nodule (N) were measured under a microscope and compared between both groups. The mean N/G ratio of the pseudoinvasive tumors (1.73 +/- 0.46) indicated a significantly higher value than that of the microinvasive tumors (1.04 +/- 0.06; P < 0.01). The N/G ratio could be one of the indices used to distinguish a pseudoinvasive tumor from a microinvasive tumor in colorectal polypoid tumors.