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Results for “Carcinoma, Merkel Cell”

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At least 19 recordsLinked to original sources

PubMed2002

Primary undifferentiated small cell carcinoma (Merkel cell carcinoma) in a patient after heart transplantation--case report.

Here we report a case of a 48-year-old man after heart transplantation in whom two years after the procedure an appendage germ tumour was diagnosed and a year after its removal in the same area a primary undifferentiated small cell carcinoma (Merkel cell carcinoma) with metastases to the axillary lymph nodes was detected. The diagnosis of Merkel cell carcinoma was confirmed by immunohistochemical staining showing a typical perinuclear expression of cytokeratin 20 with the absence of reactivity with wide spectrum cytokeratin and the presence of neuroendocrine markers of neurone-specific enolase and chromogranin. Primary undifferentiated small cell carcinoma occurs more frequently in patients receiving immunosuppressive treatment as compared with a general population and occurs much more frequently in those below 50 years of age.

Carcinoma, Merkel Cell↗

PubMed2003

Cutaneous undifferentiated small (Merkel) cell carcinoma, that developed synchronously with multiple actinic keratoses, squamous cell carcinomas and basal cell carcinoma.

Merkel Cell Carcinoma (MCC) is an uncommon undifferentiated neuroendocrine tumor, arising in skin mainly on sun-exposed areas. We present an unusual case of primary cutaneous undifferentiated small cell carcinoma that co-existed with six other lesions; 2 actinic keratoses, 3 squamous-cell carcinomas and a basal-cell carcinoma. HE stained sections revealed MCC located in the mid-dermis, co-existing with severe actinic keratosis. Immunohistochemically, the tumor cells reacted to cytokeratin 20, epithelial membrane antigen, chromogranin and neuron specific enolase. This is an unusual case of cutaneous MCC co-existing with six other different lesions. The concurrent development of MCC, squamous-cell and basal-cell carcinoma in the same patient indicates the pluripotent epidermal stem cell origin of these tumors. Further research is needed to enlighten the factors inducing this divergent differentiation.

Aged↗

PubMed2001

Telomerase activity of Merkel cell carcinomas and Merkel cell carcinoma-derived cell cultures.

Merkel cell carcinomas are rare malignant tumors of the skin, which are predominantly observed in elderly patients (mean age 65-70 years). It is believed but not yet proven that these tumors are derived from the Merkel cells of the epidermis and hair follicles. The Merkel cells themselves probably originate from an asymmetric cell division of basal keratinocytes and the resulting differentiated Merkel cells have presumably, at least in humans, lost their growth potential. The capability of indefinite cell division in germ line cells and in the great majority of malignant tumors as well as an increased growth potential in certain somatic cells (such as basal cells of renewable tissues) is correlated with cellular telomerase activity, which is absent in differentiated somatic cells. In this study the telomerase activity in cryostat sections of frozen Merkel cell tumor biopsies and in in vitro cultivated Merkel cell carcinoma cells was analyzed. We detected telomerase activity in four tumors and three of four cell cultures. These results show that despite their pronounced neuroendocrine differentiation and their occurrence in patients of advanced age, Merkel cell carcinomas possess telomerase activity similar to that of common carcinoma types.

Aged↗

PubMed1999

Cytokeratin 20: a marker for diagnosing Merkel cell carcinoma.

Merkel cell carcinoma is an aggressive cutaneous neoplasm that is often difficult to diagnose because of its histologic and immunohistochemical similarity to metastatic oat cell carcinomas and other cutaneous neoplasms. Our purpose was to determine the utility of immunoperoxidase staining of cytokeratin 20 (CK 20), a newly discovered intermediate filament protein, in Merkel cell carcinomas and other cutaneous tumors. Sixty-one tumors were sectioned and stained with antibodies directed at CK 20. The staining of Merkel cell carcinomas was compared with metastatic oat cell carcinomas, lymphomas, squamous cell carcinomas, basal cell carcinomas, melanomas, metastatic carcinoids, spiradenomas, eccrine carcinomas, adenoidcystic carcinoma, sebaceous carcinomas, hidradenomas, sebaceous epitheliomas, trichoblastomas, mixed tumors, and metastatic adenocarcinomas. Nine of 10 Merkel cell carcinomas stained with antibody to CK 20. Two metastatic carcinomas to the skin were also positive. One hidradenoma and one squamous carcinoma exhibited focal staining, but were otherwise negative. All other tumors were nonstaining. Cytokeratin 20 is a sensitive and specific marker for Merkel cell carcinoma and is helpful in distinguishing between Merkel cell carcinoma and other malignant and benign neoplasms.

Biomarkers, Tumor↗

PubMedDate not supplied

Non random cytogenetic changes characterize Merkel cell carcinoma.

Merkel cell carcinoma is a rapidly proliferating neoplasm of neuroectodermal origin presenting in skin. Karyotypes obtained in direct preparations of three Merkel cell carcinomas were analyzed and compared with six other tumors which were reported in the literature. Of the nine tumors studied so far, eight (89 per cent) showed structural abnormalities of chromosome 1. These abnormalities were in the form of trisomy for chromosome 1q22----ter. Furthermore, it was also observed that the breaks of these rearrangements on chromosome 1 occurred at the bands to which c-oncogenes N-ras (p31), L-myc (p32), c-src (p36), c-ski (q22-22), and the beta-subunit of the nerve growth factor (NGF) (p22) were localized. In addition to structural changes, five out of the nine tumors (55.5 per cent) were trisomic for chromosome 1. Merkel cell tumors are often confused with small cell carcinoma of lung or peripheral neuroepithelioma. The cytogenetic abnormalities such as rearrangement of chromosome 3p and t(11;22)(q23;q12) which characterize lung carcinoma and peripheral neuroepithelioma, respectively, were not seen in any of the nine Merkel cell tumors studied. Thus it appears that rearrangement of chromosome 1 was non-randomly associated with Merkel cell carcinoma. It is of interest to note that genes involved in neuronal development and or differentiation have been mapped to the bands at which breaks occurred in these tumors. The significance of these changes is briefly discussed.

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PubMed1999

Sentinel-node guided lymph-node dissection for merkel cell carcinoma.

Merkel cell carcinoma is an aggressive neuroendocrine skin tumour. Treatment is still debatable. Merkel cell carcinoma resembles malignant melanoma in its cutaneous presentation and its embryonic origin; both have unpredictable biological behaviour, early regional lymph node involvement, early distant metastases and a high recurrence rate. In light of these common features, we used pre-operative lymphoscintigraphy, intraoperative lymph-node mapping and sentinel-node biopsy-a well-described technique for the treatment of melanoma-in a 60-year-old man with Merkel cell carcinoma in the right buttock. Following frozen section identification of a metastatic first-order sentinel node, radical right groin dissection was performed. All the other lymph nodes in this basin proved to be disease-free, including the second-order sentinel node and Cloquet node. The patient is now being treated with adjuvant chemotherapy and radiotherapy. This case shows that sentinel-node guided dissection is applicable to Merkel cell carcinoma.

Carcinoma, Merkel Cell↗

PubMed2002

[Merkel cell carcinoma].

Merkel cell carcinoma (cutaneous neuroendocrine carcinoma) is an uncommon, highly malignant, neuroendocrine skin tumour. Typically, the primary is a fast-growing tough dermal nodule that is characterized histologically by uniform round cells with a small cytoplasmic rim. The tumour cells express the cytokeratins 8, 18, 19, 20, neurofilament, synaptophysin, chromogranin, and neuron-specific enolase. A high frequency of local recurrences (25-77%) and lymph-node metastases (50%) are characteristic features of Merkel cell carcinoma. The 5-year survival rate is 30-74%. Merkel cell carcinomas are highly radiosensitive. Thus, besides surgical methods, radiation should be included into the treatment concept in every stage. We present four cases of Merkel cell carcinoma with different courses for a review-like discussion of this disease giving instructions for rapid diagnosis and effective therapy.

Aged↗

PubMed2004

[Merkel cell carcinoma].

Merkel cell carcinoma is a neuroendocrine tumor of the skin, originating from neuroendocrine cells. A case report of Merkel cell carcinoma, discovered in a 77-Year-old woman, was diagnosed and confirmed on a biopsy. Diagnostic and therapeutic orientations of this unusual but malignant tumor are described.

Aged↗

PubMed1990

Presumed choroidal metastasis of Merkel cell carcinoma.

Merkel cell carcinoma is a rare skin tumor of neural crest origin and is part of the amine precursor uptake and decarboxylase system. It typically occurs on the face of elderly people. Distant metastasis is almost uniformly fatal. Choroidal metastasis, to our knowledge, has not been described. We report a patient with Merkel cell carcinoma who had a synchronous solid choroidal tumor and a biopsy-proven brain metastasis. Our 56-year-old patient presented with a rapidly growing, violaceous preauricular skin tumor. Computed tomography of the head disclosed incidental brain and choroidal tumors. Light and electron microscopy of biopsy specimens of both the skin and the brain lesions showed Merkel cell carcinoma. Ophthalmoscopy, fluorescein angiography, and A and B echography revealed a solid choroidal mass. The brain and skin tumors responded well to irradiation. A radioactive episcleral plaque was applied subsequently to the choroidal tumor. All tumors regressed, and the patient was doing well 28 months later. To our knowledge this is the first case of presumed choroidal metastasis of Merkel cell carcinoma.

Biopsy↗

PubMed2004

Complementary role of positron emission tomography in merkel cell carcinoma.

Merkel cell carcinoma is a rare type of neuroendocrine tumor of the skin with approximately 470 documented new cases annually in the United States. These tumors have high metastatic and recurrence rates, making them aggressive and difficult to treat. Diagnostic workup usually includes computed tomography, magnetic resonance imaging, and scintigraphy methods such as octreotide scans. More recently, positron emission tomographic scanning has been used to evaluate Merkel cell carcinomas. A case of Merkel cell carcinoma, in which positron emission tomography imaging with fluorodeoxyglucose played an important role in staging, re-staging, and identifying previously unknown distant metastatic disease, is presented in this article.

Antineoplastic Agents↗

PubMed2001

Management of Merkel cell carcinoma.

Merkel cell carcinoma is an uncommon cutaneous malignancy. Although it is rare, Merkel cell carcinoma has been described as the most malignant primary skin tumor. It is therefore important that once diagnosed, Merkel cell carcinoma is treated appropriately. The aim of this short review is to provide a summary of the available literature to guide clinicians in the future management of such patients. Inevitably in such a rare disease, there are no randomized trials of therapy. The treatment of individual patients will rely on opinion as much as the 'evidence'.

Carcinoma, Merkel Cell↗

PubMed1992

[The effectiveness of radiotherapy for Merkel cell carcinoma].

Merkel cell carcinoma is a high-grade malignant tumor of the skin that tends to extend locally and metastasize to regional lymph nodes. Surgical resection is the treatment of choice, and the effectiveness of radiotherapy for this disease has not yet been established. We report two cases of biopsy-proven Merkel cell carcinoma effectively treated with radiotherapy. Histopathological examination of the resected specimens after radiotherapy of 50 Gy and 38 Gy, respectively, using 6 approximately 15 MeV electrons showed no malignant cells in either case. No evidence of recurrence or metastasis has been noted in 11 to 21 months after radiotherapy. To our knowledge, no case of Merkel cell carcinoma in which complete cure was obtained by radiotherapy alone has been reported previously. It is considered that preoperative radiotherapy would contribute to the management of this locally invasive but radiosensitive tumor.

Aged↗

PubMed1996

Aberrant FHIT transcripts in Merkel cell carcinoma.

Merkel cell carcinoma is a rare neuroendocrine carcinoma of the skin which shares several features with small cell lung carcinoma. In a previous study, we reported a high frequency of abnormalities of the FHIT gene, located at 3p14.2, in small cell lung tumors. To determine the role of the FHIT gene in small cell neuroendocrine malignancies, 14 cases of Merkel cell carcinoma were analyzed by reverse transcription of FHIT mRNA followed by PCR amplification and sequencing of products. Eight of 14 tumors (57%) displayed abnormal FHIT products that lacked three or more exons of the FHIT gene. The pattern of abnormal transcripts was similar to that observed in small cell lung tumors, suggesting that FHIT abnormalities might be a common genetic marker of these two types of neuroendocrine tumors.

Acid Anhydride Hydrolases↗

PubMed1989

Merkel cell carcinoma.

Merkel cell carcinoma is an unusual primary cutaneous tumor with an aggressive biologic nature. Following surgical treatment, 40% of patients have local recurrences develop, 55% have regional lymph node metastases develop, and 49% have distant metastases develop. We have treated four patients with Merkel cell carcinoma; only one of the four patients was alive and well after 2 years. Two patients died of metastatic disease, one at 11 months following initial treatment and one at 39 months. The fourth patient had a rapid recurrence following initial treatment and is currently in remission following chemotherapy for regional metastases. Recent reports indicate that chemotherapy may be helpful in treating patients with recurrent or metastatic Merkel cell carcinoma.

Age Factors↗

PubMed2001

Paraneoplastic and metastatic neurologic complications of Merkel cell carcinoma.

Merkel cell carcinoma is a rare primary cutaneous neuroendocrine tumor that is locally aggressive and frequently accompanied by distant metastases. Neurologic complications of Merkel cell carcinoma are rare. We describe a 69-year-old man who presented with Lambert-Eaton myasthenic syndrome and was found to have Merkel cell carcinoma. The paraneoplastic syndrome improved with initial treatment of the malignancy. He subsequently developed a solitary brain metastasis and died of leptomeningeal carcinomatosis.

Aged↗

PubMed2003

[Total hip arthroplasty for metastatic Merkel cell carcinoma].

Merkel cell carcinoma is an extremely rare malignant tumor which derives from the neuroendocrine cell system with features of epithelial differentiation. It belongs to the APUD-system (amine and precursor uptake and decarboxylation) and is characterized by highly aggressive spread with a predisposition for local recurrence and local regional and distant metastases. Metastatic spread to the hip has not been described in the literature before. We report on a 76-year old male patient with metastases of the left femoral head and greater trochanter 3 1/2 years after excision of a Merkel cell carcinoma of the left thigh with consecutive radical lymph node dissection of the left inguinal area and radiation therapy. Although microscopic,immunohistological and ultrastructural characteristics of the carcinoma have been well defined, there are no established treatment guidelines and prognostic factors that may predict the behaviour of the tumor due to the limited number of cases. Elective lymph node dissection decreases the rate of local recurrence but is not associated with improved overall survival. At the time of establishing the diagnosis, about half of the patients has positive lymph nodes with a 3-year-survival rate of 60%.

Aged↗

PubMed2000

Postoperative hyponatremia in a patient with ACTH-producing Merkel cell carcinoma.

Merkel cell carcinoma is characterized by specific neuroendocrine features and the expression of several neuropeptides. We report a case of Merkel cell carcinoma with post-surgical hyponatremia in an 85-year-old Japanese woman. A tumor on the left cheek histopathologically showed the characteristics of Merkel cell carcinoma together with Bowen's disease. Although an increased level of ACTH was found both in the tumor and in the peripheral blood, the postoperative hyponatremia in our patient seems more likely to have been caused by the stress of the operation and indapamide, considering that the ACTH level in the tumor was much lower than those in other ectopic ACTH-producing tumors in previous reports.

Adrenocorticotropic Hormone↗

PubMed1985

Chemotherapy for metastatic Merkel cell carcinoma.

Merkel cell carcinomas (also known as trabecular carcinomas) are primary cutaneous small cell neuroendocrine neoplasms with the potential to metastasize. Control of disseminated disease is therefore important. A case of metastatic Merkel cell carcinoma with an excellent response to chemotherapy is presented. The regimen chosen for this case is similar to that used for bronchogenic small cell anaplastic carcinoma. The reason for selecting this regimen was the common neuroendocrine differentiation and the similar histopathologic features of these two tumors. Only a few reports have described chemotherapy for Merkel cell carcinoma and similar agents were used. These cases are reviewed and critically analyzed.

Adenocarcinoma↗