Trisomy of chromosome 6 in Merkel cell carcinoma within lymph nodes

Merkel cell carcinoma (MCC) of the skin is a neuroendocrine tumor with characteristic histological and immunohistochemical features. Among various cytogenetic changes, trisomy of chromosome 6 has been reported in 47% of cases using in situ hybridization. Primary tumors, morphologically and immunohistochemically identical to MCCs of the skin, have been described in other organs, including lymph nodes. Here, a cytogenetic study of four cases of MCC of lymph nodes is presented. Four cases of primary MCCs of lymph nodes and ten cases of cutaneous MCCs were studied for chromosome 6 using fluorescent in situ hybridization (FISH). All cases showed typical features of MCC both at hematoxylin and eosin (H&E) and immunohistochemistry. FISH showed trisomy 6 in two out of the four cases of MCCs of lymph node as well as in 6 out 10 cases of MCCs of skin. Lymph nodal and cutaneous MCCs share same histological and immunohistochemical features, as well as same cytogenetic alteration for chromosome 6. It seems that there are more similarities than differences between cutaneous and lymph nodal MCCs. Whether lymph nodal MCCs are primary tumors or metastases from regressed skin lesions is still questionable, although several findings indicate a primary origin.     

Association of Merkel cell polyomavirus infection with morphologic differences in Merkel cell carcinoma

Recently, it has been shown that approximately 80% of Merkel cell carcinomas harbor a novel polyomavirus named Merkel cell polyomavirus, thought to be a carcinogenic agent. However, it is not fully elucidated whether Merkel cell carcinomas differ with regard to the presence or absence of Merkel cell polyomavirus. To address this, we investigated morphologic differences between Merkel cell polyomavirus-positive and -negative Merkel cell carcinomas by morphometry. Using polymerase chain reaction and real-time quantitative polymerase chain reaction, Merkel cell polyomavirus was detected in 20 (77%) of 26 Merkel cell carcinoma cases, including 4 Merkel cell carcinomas combined with squamous cell carcinomas. Interestingly, Merkel cell polyomavirus was detected only in ordinary (pure) Merkel cell carcinomas; none of the 4 combined Merkel cell carcinomas + squamous cell carcinomas was positive for Merkel cell polyomavirus (P = .001). Morphometric analyses revealed that Merkel cell polyomavirus-negative Merkel cell carcinomas had more irregular nuclei (P < .001) and more abundant cytoplasm (P = .001) than Merkel cell polyomavirus-positive Merkel cell carcinomas, which had uniform round nuclei and scant cytoplasm. Reliability of the morphometry was confirmed using intraobserver and interobserver reliability tests. These results demonstrated statistically significant differences in tumor cell morphology between Merkel cell polyomavirus-positive and -negative Merkel cell carcinomas and reconfirmed the absence of Merkel cell polyomavirus in combined tumors. Furthermore, the results strongly suggest fundamental biological differences between Merkel cell polyomavirus-positive and -negative Merkel cell carcinomas, supporting that Merkel cell polyomavirus plays an important role in the pathogenesis of Merkel cell polyomavirus-positive Merkel cell carcinoma.     

Observations by chromosome banding, FISH and immunohistochemistry in an adenoid cystic carcinoma with del(17)(p13) as the sole deviation

We report on an adenoid cystic carcinoma (ACC) with a clonal deletion of 17p as the only karyotypic abnormality. Using different chromosome 17-derived probes we showed by FISH that the deletion encompassed thep53 tumour suppressor gene. Immunohistochemical analysis revealed overexpression ofp53 protein in a subpopulation of cells, suggesting a mutation in the remainingp53 allele in these cells. Our findings provide novel information about possible progressional pathways in ACC, and demonstrate the value of combining conventional cytogenetic analysis with molecular cytogenetic and immunohistochemical methods. This approach is particularly useful in cases with minor cytogenetic abnormalities at the border of visibility.     

Analysis of chromosomal imbalances in an elderly woman with a giant cell tumour

Giant cell tumour (GCT) remains one of the most obscure and intensely studied bone tumours. In an effort to resolve questions regarding the genesis and clinical outcome of GCT, advances have been made recently in the identification of chromosomal abnormalities implicated in the tumour. Fusion of telomeres is very frequent in GCT, and this process may be associated with chromosome instability and tumour development. However, little emphasis has been placed on chromosomal imbalances in the molecular characterization of this disease. Here, we report the case of an 83-year-old woman diagnosed with GCT where local recurrence was observed after 11 months of the resection. Cytogenetic studies of the GCT showed a modal number of 46 chromosomes with telomeric associations on 11p and dicentric chromosomes. Moreover, clonal abnormalities, such as del(17p) and losses of chromosomes 4, 13 and 18 and gains on chromosome 7, were also detected. Interestingly, comparative genomic hybridisation (CGH) analysis revealed chromosomal imbalances with gains on chromosomes 1p31-q44, 6q12-q23 and 12q15-q22. Thus, the use of CGH expanded the information obtained by conventional cytogenetics and demonstrated that chromosomal imbalances were associated with the recurrence of the GCT.     

The spectrum of Merkel cell polyomavirus expression in Merkel cell carcinoma, in a variety of cutaneous neoplasms, and in neuroendocrine carcinomas from different anatomical sites

Most Merkel cell carcinomas display pure neuroendocrine differentiation (pure Merkel cell carcinoma), whereas a minority show combined neuroendocrine and nonneuroendocrine elements (combined Merkel cell carcinoma). Recent identification of Merkel cell polyomavirus DNA and Merkel cell polyomavirus large T antigen expression in a proportion of Merkel cell carcinomas has suggested viral-induced oncogenesis. To date, Merkel cell polyomavirus immunohistochemistry has shown an absence of viral large T antigen expression in combined Merkel cell carcinoma as well as select non-Merkel cell carcinoma cutaneous lesions and visceral neuroendocrine tumors. In our series, we aimed to further characterize the frequency and pattern of Merkel cell polyomavirus large T antigen expression by CM2B4 immunohistochemistry in primary and metastatic Merkel cell carcinoma (pure Merkel cell carcinoma and combined Merkel cell carcinoma) and various non-Merkel cell carcinoma lesions from patients with Merkel cell carcinoma, patients without Merkel cell carcinoma, and individuals with altered immune function. Merkel cell polyomavirus large T antigen was detected in 17 (63%) of 27 pure Merkel cell carcinomas and absent in all 15 (0%) combined Merkel cell carcinomas. Furthermore, complete concordance (100%) of Merkel cell polyomavirus large T antigen expression was observed in 10 cases of primary Merkel cell carcinoma and subsequent tumor metastases. We also evaluated 70 non-Merkel cell carcinoma lesions including 15 cases each of pulmonary and gastrointestinal neuroendocrine tumors. All 70 non-Merkel cell carcinoma lesions were negative for Merkel cell polyomavirus by CM2B4 immunohistochemistry, irrespective of any known Merkel cell carcinoma diagnosis and immune status. In summary, our identification of Merkel cell polyomavirus large T antigen expression in a subset of Merkel cell carcinoma and lack of findings in combined Merkel cell carcinomas and non-Merkel cell carcinoma lesions concur with earlier findings and implicate Merkel cell polyomavirus-independent pathogenesis in these cases. Overall, CM2B4 immunohistochemistry appears to be a specific method for Merkel cell polyomavirus detection and has the potential to play an important role in the diagnosis and classification of Merkel cell carcinoma in the future.     

Neuroendocrine carcinoma of the breast with Merkel cell carcinoma-like features

A case of neuroendocrine carcinoma of the breast with Merkel cell carcinoma-like features occurring In a 38-year-old female Is described. A 2.5 × 2.5 × 1.3 cm tumor in the upper-outer quadrant of the right breast was ill-defined, yellowish white and rubbery. Microscopically, the tumor was characterized by a diffuse proliferation of non-cohesive round cells. The tumor cells had round nuclei with finely dispersed chromatin and inconspicuous nucleoli. The cytoplasm was generally scant, pale to eosinophilic, and argyrophilic. There were scattered foci of small nests or intraductal proliferations. Immunohistochemically, many tumor cells showed positive reaction for CAM5.2, vimentin, chromogranin A, and synaptophysin. The tumor was also positive for neuron-specific enolase (NSE), Leu-7, calci-tonin, S-100 protein, and glial fibrillary acidic protein. Flow cytometric analysis showed that the tumor was DNA diploid. An axillary lymph node was positive for metastasis. The patient was well, without disease, for 6 years after mastectomy. It is suggested that the tumor might originate from ductal cells and show Merkel cell carcinoma-like neuroendocrine differentiation.     

Immunohistochemical and ultrastructural investigation on cutaneous neuroendocrine carcinoma: report of a case and review of the literature

We report a tumor in an 80-year-old man that was difficult to distinguish from other tumors, i.e., small cell carcinoma of the lung, PNET/Ewing tumor, malignant lymphoma, or malignant melanoma (amelanotic), and which was finally identified as cutaneous neuroendocrine carcinoma using immunohistochemical and ultrastructural methods. Autopsy did not show any tumors in the lungs, excluding the possibility of small cell carcinoma of the lung. Immunohistochemistry tests gave negative results for LCA, UCHL-1, CD3, and CD20, thereby excluding malignant lymphoma, and the negative results for S-100 protein and HMB-45 ruled out malignant melanoma. The possibility of PNET/Ewing sarcoma was also excluded because of negativity for CD99. In addition, the ultramicrostructure showed intercellular junctional complexes and neuroendocrine granules, indicating that the tumor had characteristics of both epithelial and neuroendocrine tissues. We therefore diagnosed the primary carcinoma of the skin as cutaneous neuroendocrine carcinoma.     

High load of Merkel cell polyomavirus DNA detected in the normal skin of Japanese patients with Merkel cell carcinoma

BackgroundAlthough Merkel cell polyomavirus (MCPyV) has the potential to cause Merkel cell carcinoma (MCC), it is also found in the normal skin of healthy individuals. However, the mechanism for transformation of MCPyV to an oncogenic form is unknown.ObjectivesTo investigate the levels of MCPyV infection in the normal skin patients with MCC compared with those in a control cohort.Study designWe studied a total of six Japanese patients with cutaneous MCC. Sun-exposed and sun-unexposed skin swabs were obtained and analyzed for MCPyV loads using quantitative real-time polymerase chain reaction.ResultsAt first, we found a patient with MCC carrying an extremely high load of MCPyV DNA in normal skin. This unique case prompted us to further explore the levels of MCPyV as skin microbiota in patients with MCC. We showed that MCPyV DNA levels were significantly higher in swabs obtained from normal skin samples of six patients with MCC compared with those from 30 age-matched healthy individuals and 19 patients with other cutaneous cancers. Whereas MCPyV strains obtained from the normal skin of patients with MCC had gene sequences without structural alterations, sequences of the tumor-derived strains showed truncating mutations or deletions.ConclusionsAlthough the number of patients with MCC studied was small, our findings suggest that MCC may occur with a background of high MCPyV load in the skin, and are expected to stimulate further studies on whether such skin virome levels could be one of predictive markers for the development of MCC.     

Merkel cell carcinoma presenting as a malignant pleural effusion post-COVID-19 hospitalization: A case report and literature review

Merkel cell carcinoma (MCC) is a rare, highly aggressive neuroendocrine carcinoma of the skin, associated with immunosuppression, UV light exposure, and the Merkel cell polyomavirus (MCPyV). Cases of metastatic MCC diagnosed in body fluid cytology are extremely rare; only five cases have been reported previously in the English literature. We present a case of a 65-year-old male with acute respiratory failure and an enlarged right pleural effusion. He had two hospitalizations for COVID-19 pneumonia 2 months prior, for which he received steroid treatment and tocilizumab. Emergent thoracentesis was done, with pleural fluid sent for cytologic evaluation. Both the Papanicolaou stained ThinPrep slide and cell block demonstrated clusters of predominantly small to medium sized blue round cells with hyperchromatic nuclei, scant cytoplasm and fine chromatin, in a background of rare mesothelial cells, macrophages and numerous lymphocytes. Tumor cells were positive for CD56, chromogranin, synaptophysin, SAT2B, MCPyV, and CK20 in perinuclear dot like pattern, while negative for TTF-1 and CD45 immunostains. Ki67 proliferative index was approximately 40%. The patient had a history of MCC of the right ulnar forearm 4 years before the current presentation, which was unknown to us at the time of cytologic evaluation. To the best of our knowledge, this is the sixth case of metastatic MCC diagnosed by fluid cytology and the first reported in a patient receiving immunosuppressive treatment for COVID-19. Further reporting of such cases may increase awareness, especially when prior history is not readily available, such as in our case.     

Nonrandom gain of chromosome 7 in central neurocytoma: A chromosomal analysis and fluorescence in situ hybridization study

Central neurocytoma is a benign, slow-growing neoplasm with favourable prognosis. Biomolecular analysis has failed to demonstrate significant alterations, and no cytogenetic alterations have been reported. In this study we demonstrate chromosome 7 gain in three of nine neurocytomas (33%). Traditional cytogenetic analysis performed in four of the nine cases identified trisomy 7 as the sole chromosomal abnormality in one case. Interphase cytogenetics utilizing fluorescent in situ hybridization (FISH) on cell suspensions from formalin-fixed paraffin-embedded tumour tissue performed in all nine cases detected trisomy 7 in two more cases and tetrasomy in another. Our results suggest that chromosome 7 gain is a feature of neuroectodermal tumorigenesis, possibly conferring growth advantage on the neoplastic cells. FISH on interphase nuclei is a valuable adjunct in the genetic evaluation of rare central nervous system neoplasms with low baseline proliferative activity.     

Trisomy 1 and 8 occur frequently in hepatocellular carcinoma but not in liver cell adenoma and focal nodular hyperplasia. A fluorescence in situ hybridization study

Conventional cytogenetic studies revealed gains and structural aberrations of chromosome 1 to be the most consistent chromosomal aberrations in hepatocellular carcinoma (HCC). We investigated touch preparations of eight HCC, five cholangiocellular carcinomas (CCC), five liver cell adenomas (LCA), four focal nodular hyperplasias (FNH) as well as nine specimens of normal liver tissue using fluorescence in situ hybridization (FISH) with centromere specific probes for chromosomes 1 and 8. Polysomies of chromosome 1, especially trisomy 1, were found in five of eight HCC and four of five CCC but in no normal liver tissue or benign tumour. Only three of seven cases of HCC revealed trisomy 8 whereas the five benign liver tumours and all normal liver tissues examined had disomy 8. Our results confirm conventional cytogenetic findings in terms of chromosome 1 aberrations in HCC although they are not specific for these types of malignant liver tumours. Since -satellite probes were used in our study, only gains or losses including the centromeric regions of the chromosomes 1 and 8 could be detected. Nevertheless, our findings suggest that FISH may help in the differential diagnosis of malignant versus benign neoplasms of the liver.     

股部鲍温病1例

报告1例股部鲍温病.患者男,80岁.右股部出现红色斑片10年就诊.皮肤科检查:右股部可见境界清楚的红斑,表面灰色结痂,湿润的糜烂面,面积约5 cm×8 cm大小.组织病理检查结果符合鲍温病.     

Fine-needle aspiration of Merkel cell carcinoma of the skin with cytomorphology and immunocytochemical correlation

Merkel cell carcinoma (MCC) of the skin is a rare, primary malignant skin neoplasm which can present as a cutaneous nodule. These neoplasms are seen primarily in the elderly and located in the head and neck area or extremities. Twenty-nine aspirates from primary and metastatic lesions obtained by percutaneous fine-needle aspiration in 19 patients have been studied. The cytomorphologic features, clinical information, and immunocytochemical (ICC) findings are detailed. Aspirate smears demonstrated small-to-intermediate-sized cells with a loosely cohesive pattern. Nuclei were round with finely granular chromatin and multiple, small nucleoli. Cells possessed a thin rim of cytoplasm, and infrequent pseudorosette formations were noted in cell groups. ICC results were universally positive for cytokeratin, which showed a paranuclear “dot-like” pattern. Neuron-specific enolase, epithelial membrane antigen, and S-100 protein were positive in varying degrees. Leukocyte common antigen was universally negative. The diagnosis of MCC of the skin by FNA can be made by applying cytologic features in addition to ancillary studies and clinical information. Diagn. Cytopathol. 1998;18:251–257. © 1998 Wiley-Liss, Inc.     

Monosomy 9q and trisomy 16q in a case of congenital solitary infantile myofibromatosis

Although infantile myofibromatosis (IM) is the most common fibrous proliferation of infancy, many aspects of this benign lesion have not been explored. IM histogenesis is still poorly understood, despite immunohistochemical staining and ultrastructural features that suggest a myofibroblastic origin. IM diagnosis is often made difficult by the predominance of small primitive spindle cells over myofibrobasts and the presence of intravascular growth. Genetic information is scarce, with only one karyotyped case. Here we describe a case of solitary IM discovered at birth in an otherwise healthy girl. The tumor was well circumscribed, arranged in nodules and made up of ovoid cells without atypia, in a myxoid background. Immunohistochemical evaluation indicated a myofibroblastic differentiation. The cytogenetic and fluorescence in situ hybridization analyses revealed an abnormal chromosome 9, derived from an unbalanced whole-arm translocation between chromosomes 9 and 16. On both chromosomes, the breakpoints were located in the pericentric heterochromatic region. This clonal abnormality has not been reported in other tumors and is different from the chromosome 6q deletion reported in the single previous reported IM karyotype.     

Clinical and genetic study of Japanese patients with type 3 Gaucher disease

Information on the phenotypic variations seen in patients with type 3 (chronic neuronopathic) Gaucher disease (GD) is still limited compared with type 1 GD. We retrospectively investigated the clinical features of 42 Japanese patients with type 3 GD. The 42 patients classified as type 3 fell into two groups: those diagnosed as having type 3 GD at diagnosis (group A; n = 24) and those thought to have type 1 at diagnosis but who later developed neurological symptoms (group B; n = 18). The genotype of group A patients varied widely; however, L444P/L444P and L444P/F213I genotypes accounted for 83% in group B. All the patients who did not receive enzyme replacement with alglucerase or imiglucerase (4 in group A, 2 in group B) died. Nineteen patients received enzyme replacement in group A; however, 7 of these died despite the therapy. On the other hand, 14 patients received enzyme replacement alone in group B and 13 of them survived. Among the ERT-treated patients who survived, only one of 12 in group A and 12 out of 13 in group B can walk unaided. In conclusion, some Japanese GD patients who are thought to have type 1 at diagnosis develop neurological symptoms during their clinical course, and careful observation is essential for patients with characteristic genotypes. Moreover, enzyme replacement alone might not have a sufficient effect on the early onset neurological symptoms in type 3 patients. A different treatment strategy is needed to improve the prognosis of these patients.     

Detection of Merkel cell polyomavirus in Merkel cell carcinoma and Kaposi's sarcoma

Merkel cell carcinoma is a rare malignancy that sometimes occurs in the skin of elderly people. Recently, a new human polyomavirus, Merkel cell polyomavirus (MCPyV) was identified in Merkel cell carcinoma. In the present study, MCPyV‐DNA was detected in 6 of 11 (55%) cases of Merkel cell carcinoma by nested PCR and real‐time PCR. Histologically, MCPyV‐positive cases showed round and vesicular nuclei with a fine granular chromatin and small nucleoli, whereas MCPyV‐negative cases showed polygonal nuclei with diffusely distributed chromatin. Real‐time PCR analysis to detect the MCPyV gene revealed that viral copy numbers ranged 0.04–0.43 per cell in cases of Merkel cell carcinoma. MCPyV was also detected in 3 of 49 (6.1%) cases of Kaposi's sarcoma (KS), but not in 192 DNA samples of other diseases including 142 autopsy samples from 20 immunodeficient patients. The MCPyV copy number in KS was lower than that in Merkel cell carcinoma. PCR successfully amplified a full‐length MCPyV genome from a case of KS. Sequence analysis revealed that the MCPyV isolated from KS had 98% homology to the previously reported MCPyV genomes. These data suggest that the prevalence of MCPyV is low in Japan, and is at least partly associated with the pathogenesis of Merkel cell carcinoma. J. Med. Virol. 81:1951–1958, 2009. © 2009 Wiley‐Liss, Inc.