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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.
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.
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.
Merkel cell carcinoma is a rare malignant neoplasm of the skin which is locally invasive and frequently metastasizes to lymph nodes, liver, lungs, bone, and brain. Computed tomographic and pathologic findings in an elderly woman with Merkel cell carcinoma of the buttock and regional nodal metastasis are reported. The presence of calcitonin and neuron-specific enolase within the tumor supports the theory that Merkel cell carcinoma is a neuroendocrine tumor derived from the APUD (amine precursor uptake and decarboxylase) system.
Merkel cell carcinoma (MCC) is a malignant tumor of the skin with a well-established neuroendocrine phenotype but an unknown histogenetic origin. Cytogenetic and molecular studies have shown evidence for genetic changes on the distal portion of chromosome 1p in different tumors with well-established neuroendocrine origins, specifically neuroblastomas, malignant melanomas, and pheochromocytomas. Involvement of chromosome 1 in MCC recently has been demonstrated by cytogenetic analysis and analysis of loss of heterozygosity (LOH) in metastatic tumor tissue. We performed analysis of LOH of the distal portion of chromosome 1p in paraffin material of 10 primary MCCs after tissue microdissection, using the polymorphic markers D1S160, D1S243, D1S468, D1S1646, and D1S1598. Seven of 10 analyzed MCCs shared a distal deletion involving 1p35-36. None of the cases showed 1p involvement proximal to 1p35. The findings are similar to those described for malignant melanoma, pheochromocytoma, and neuroblastoma, tumors known to originate from neural crest cells. In conjunction with previous cytogenetic data, we conclude that Merkel cell carcinogenesis shares pathogenetic mechanisms with other neoplasms of neural crest derivation.
The state of the tactile cells (Merkel's cells) in epithelium of the internal follicle in the cat sinuous hairs is controlled by sensitive neurons. This statement, derived from the experiments on denervation, was analysed in the investigation when colchicine (an agent blocking axoplasmic transport) was applied on the nerve. Thirty and 60 days after colchicine effect a statistically important decrease in the number of the tactile cells with certain changes in their structure (cytoplasmic consolidation, changes in density of specific granules, increasing number and size of vacuoles) was registered. In epithelium of the internal hairy follicle a contact of the tactile cells with tactile menisci was followed. As in myelin neural fibres of the internal hairy follicle connective tissue, certain signs of destruction, resulting from blockade of colchicine-induced axoplasmic transport, were noted. Participation of the axoplasmic transport in the neurosensory control for the state of the tactile cells is discussed together with the changes described.
Merkel cell carcinoma is a rare cutaneous neoplasm most commonly affecting the head and neck of elderly white patients. Even with treatment, Merkel cell carcinoma has a strong propensity toward local recurrence, lymphatic spread, and distant metastasis. Because of its rarity and the subsequent lack of well-controlled clinical trials, no single standard of care exists for the treatment of this aggressive tumor. In our institution, primary lesions are excised with wide margins or by Mohs' micrographic surgery. After local removal, the excision site is treated locally with external radiation therapy. Sentinel lymph node mapping and biopsy are performed. Patients with tumor within a sentinel lymph node undergo lymph node dissection and radiation to the lymphatic basin. Adjuvant chemotherapy is offered to high-risk patients with local disease and to patients with metastases. Patients with distant metastases are treated with a combination of salvage chemotherapy and radiation therapy.
Merkel cell carcinoma is a rare cutaneous neoplasm with aggressive characteristics. Local recurrence following wide local excision is common. Computed tomography (CT) findings in a case of recurrent Merkel cell carcinoma are reported, with discussion of treatment options.
Merkel cell cancer is a rare carcinoma arising from the neuroendocrin cells of the skin. The diagnosis is based on the clinical behaviour, histopathologic and ultrastructural findings and immunohistochemical results. An unusual case of Merkel cell carcinoma is presented. Mass from the umbiculus and a right inguinal lymph node was excised in a 63-year-old female. The histologic features of a typical, primitive small cell tumor combined with the immunohistochemical evaluations established the diagnosis. Rare polynuclear giant cells were focally present in our case. Patient was treated with combination of chemotherapy (Cisplatin, Etoposid) and radiotherapy. Control examinations showed complete respond. One year later metastasis developed. Resection of all known metastasis were performed. Two months after the laparotomy she died of metastatic disease. The autopsy did not reveal any other primary tumor. The capricious nature of the clinical course and the differences between this tumor and other carcinomas is emphasized.
Merkel cell carcinoma is an aggressive tumor that should be treated early and aggressively. Although there are 5 published cases of spontaneous regression of Merkel cell carcinoma, a patient's best chance for survival is early detection with either wide local excision or Mohs' micrographically controlled margins with a final 5- to 10-mm layer. This should be followed by sentinel lymph node biopsy with lymph node dissection of the draining basin if metastases are discovered. Adjuvant radiation to the primary site and the draining basin should follow. Although this aggressive approach to treatment is not appropriate for every case, the literature, although scanty, supports this. Chemotherapy with or without additional radiation therapy should be offered to patients with advanced disease, mostly for palliation. The need for prospective trials and longer follow-up for larger series of patients is obvious.
Merkel cell carcinoma is a rare small cell carcinoma of the dermis with aggressive clinical features and frequent local recurrence. Intra-abdominal spread of the cancer has previously been noted primarily in the liver and retroperitoneal nodes. We report a patient with previously diagnosed Merkel cell carcinoma of the right buttock with metastases to the stomach and duodenum presenting with acute upper gastrointestinal bleeding.
Merkel cell carcinoma is a rare neuroendocrine neoplasm of the skin. The tumor most frequently affects elderly patients, with a preference for the head and neck. Eight patients affected by Merkel cell carcinoma have been observed at the General Surgery Unit II of the "Istituti Ospitalieri" hospital in Cremona, each in different stages of the disease; 75% of the cases involved the extremities, and in nearly all of the cases the tumor was nodular in appearance, with an average diameter of 2.2 cm. In 2 cases, the tumor was associated with rheumatoid arthritis, suggesting a dependency on the part of the neoplasm on the immune disorder and on steroid treatment. The available data confirm that in stage I of the disease, surgical treatment should be associated with radiotherapy in order to control the development of local relapses or metastases over time. In this stage, we observed a survival of 34 months (range, 24-48). In stages II and III, survival time falls, with very short duration of responses and poor quality of life as a result of the administration of cytotoxic molecules. Bearing in mind that any local relapse tends to appear within 12 months of the removal of the primitive tumor, that lymph node metastases appear in almost half of the patients, and that metastases over time are manifested in over a third of patients, it is essential to adopt a treatment capable of balancing the demand for longer remissions with a better quality of life. In this situation, we observed that treatment with somatostatin analogues achieves interesting responses without side effects, which suggests a close biological relationship between the tumor and somatostatin and that making a careful assessment of the prognostic factors of the disease can guarantee a correct therapeutic choice.
Merkel cell trabecular carcinoma of the skin has a prognosis poorer than expected for a small skin lesion. An early diagnosis and prompt treatment can contribute to improve survival in cases of this aggressive skin tumor. A wide local excision is indicated for localized disease. Elective lymph node dissection is controversial. The authors report a rare case of Merkel cell tumor treated with wide local excision and sentinel lymph node biopsy.
The appearance and cytodifferentiation of the Merkel cell were studied electron microscopically using the developing labial ridges of Rana japonica. The most primitive Merkel cell was identified with specific cored granules with an average diameter of about 90 nm. Such a primitive Merkel cell was found in the basal layer of the primitive labial ridge epithelium. As the primitive labial ridge continued to mature, the primitive Merkel cell accumulated an increased number of the specific granules, developed digital shaped cytoplasmic processes and came into contact with nerve fibers. When the labial ridge was sufficiently developed the cell showed typical morphological features of the mature Merkel cell except for a small accumulation of tonofilament-like structures and glycogen particles. It was also observed that the position of the Merkel cell in the epithelium changed from the basel layer to the third basal layer during development. On the other hand, it was difficult to find the Merkel cell in the mesenchymal layer of the developing labial ridges. From the results, it was suggested that the cytodifferentiation of the Merkel cell in the labial ridge of an anuran tadpole occurs within the epithelium.
Merkel cell or cutaneous neuroendocrine carcinoma is a malignant tumor with a propensity toward local and systemic recurrence. A new surgical technique, intraoperative lymphatic mapping and selective sentinel lymph node dissection (SSLND), has been demonstrated to have a high predictive value for the detection of metastatic disease in the regional lymphatic basin in cutaneous melanoma. The use of this technology may be particularly useful to accurately stage patients with Merkel cell carcinoma (MCC) because this tumor has a frequent propensity toward regional nodal metastases. Intraoperative lymphatic mapping and SSLND were performed on 6 patients with biopsy-proven MCC. Three patients with MCC had positive disease in the sentinel lymph node(s). SSLND is a feasible technique with minimal procedural morbidity to detect clinically occult disease in patients with MCC.
Merkel Cell Carcinoma (MCC) is a rare and aggressive neuroendocrine dermal neoplasm. This study is a retrospective outcomes analysis of two cases of MCC with data regarding clinical, histopathological, immunohistochemistry and also surgical, chimio and radiological treatment. MCC is a rare dermal tumors, this tumors are most predictable found on sunexposed sites. Diagnosis is best accomplished by a thorough clinical evaluation coupled with light microscopy and defined panel of immunohistochemical studies which are necessary for the definitive diagnosis of Merkel cell carcinoma (cytokeratins, neuron specific enoiase and chromogranin). A lot of other disease must be included in the differential diagnosis. MCC is an aggressive tumor with local or locoregionale extension and distant spread by hematogen or lymphatic way. Surgical excision of tumor and regional lymphadenectomy is the first step of treatment completed with radiotherapy and chemotherapy bat in advanced studies the rate of local or distant recidives is high.
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%.
Merkel cell carcinoma (MCC) is a rare, highly metastatic skin tumor of neuroectodermal origin. The disease shares clinical and histopathological features with small cell lung carcinoma (SCLC). The genetic mechanisms underlying the development and tumor progression of MCC are poorly understood. We recently showed by comparative genomic hybridization (CGH) that the pattern of chromosomal abnormalities in MCC resembles that of SCLC. One of the most frequently observed losses involved the entire chromosome 10 or partial loss of the chromosome 10 long arm (33% of examined MCC cases). The PTEN tumor-suppressor gene has been mapped to 10q23.3 and was shown to be mutated in a variety of human cancers including SCLC. Germline PTEN mutations have been observed in familial predisposing cancer syndromes including Cowden disease. Interestingly, an association between Cowden syndrome and Merkel cell carcinoma has been reported. To study the possible role of PTEN in MCC oncogenesis, loss of heterozygosity (LOH) analysis for the 10q23 region was performed on 26 MCC tumor samples from 23 MCC patients. The PTEN locus was deleted in 9 of 21 (43%) informative MCC tumor samples [7 of 18 (39%) MCC patients]. Despite this high frequency of LOH at 10q23, mutation and homozygous deletion screening of the PTEN gene revealed only one tumor with a nonsense mutation and a second with a homozygous deletion of exon 9. These data suggest that either alternative mechanisms lead to inactivation of the PTEN gene or that other tumor-suppressor genes at chromosome 10 are implicated in the development of MCC.