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PubMed1997

[Merkel cell tumor. Report of case and treatment with octreotide].

Merkel cell carcinoma is a rare neuroendocrine tumor of the skin. Prognosis is very poor particularly when systemic disease is present. Surgery, chemo and/or radiotherapy treatment are not able to guarantee long survival and quality of life is also very poor. We know that neuroendocrine tumor can be in possession of receptors for somatostatin; during the past years, these receptors have been demonstrated in vivo by octreoscan. We report a case of a patient suffering from metastatic Merkel cell carcinoma; because he was elderly, neither chemotherapy nor radiotherapy were possible as a consequence of the explosion of the disease after surgery. The presence of receptors for somatostatin analogues (octreoscan) allowed treatment with octreotide causing the immediate disappearance of metastasis. After ten months of treatment the patient presents a complete remission of disease. Octreotide, the most important somatostatin analogue, represents a primary role in the neuroendocrine tumor management; the drug also lacks of toxicity.

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PubMed1996

[Merkel cell and neuro-cutaneous system].

The Merkel cell is an epidermal neuroendocrine cell that can be identified by electron microscopy based on its neurosecretory granules or by immunolabeling based on its pattern of cytokeratin expression. Its origin is controversial but may be epidermal rather than neural. Although its functions have not been completely elucidated, there is strong evidence that it produces neuromediators, is involved in the perception of mechanical stimuli, exerts trophic and attractant effects on nerves, stimulates keratinocyte proliferation and differentiation, and plays a role in the spatial organization of the epidermis and epidermal appendages.

Carcinoma, Merkel Cell↗
PubMed2000

[Merkel cell tumor of the eyelids: review of the literature and report of 2 patients].

BACKGROUND: The Markel cell carcinoma is a rare malignant skin tumor. The tumor was first described in 1972 by Toker and he named it trabecular carcinoma. We had the opportunity to treat two patients with a Merkel cell carcinoma of the upper and lower eyelid and reviewed the literature using the "Medline" database concerning Merkel cell carcinomas of the ocular adnexa. HISTORY AND SIGNS: A 76-year-old female patient was referred to our hospital because of an inflammatory tumor of the left upper eyelid present for two months. A 91-year-old male patient noticed for four weeks a painless itching lesion at the left lower eyelid. The remaining ophthalmologic examination in these patients was unremarkable. THERAPY AND OUTCOME: Both tumors were excised. Histological and immunohistochemical examination verified a Merkel cell carcinoma in both cases. The 76-year-old female patient exhibited no recurrent tumor after a follow-up of 18 months. The 91-year-old male patient had a recurrent tumor inferior to the temporal lower eyelid 7 months after tumor excision, however, lymph node metastasis is not present as of yet. The patient underwent radiation therapy with cobalt of the left orbit with a total dose of 60 Gy. CONCLUSION: Merkel cell carcinomas can occur everywhere on the skin; the eyelids are affected in 10% of all cases. Best histochemical markers are cytokeratin 20 and neurospecific enolase. A review of the literature revealed 31 patients with Merkel cell carcinomas involving the eyelids. Female patients were more often affected than male patients. The upper eyelid was more frequently involved than the lower eyelid. Recurrent disease is frequent.

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PubMed1994

[Merkel cell carcinoma of the face. Histology, clinical course and therapy in six cases].

Six patients suffering from Merkel cell carcinoma of the face are described. A reliable confirmation and differential diagnosis of Merkel cell carcinoma have become possible with the aid of immunohistochemistry. There is a poor prognosis for patients affected by this tumour. Three out of the six cases described died within two years, two of them with distant metastases, one with a widespread local recurrence. Optimal treatment of Merkel cell carcinoma consists in early radical resection, perhaps combined with radiotherapy.

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PubMedDate not supplied

Cytology of metastatic neuroendocrine (Merkel-cell) carcinoma in pleural fluid. A case report.

A case of Merkel-cell (neuroendocrine) carcinoma of the skin with extensive metastases, including pleural effusion, occurring over 20 years after primary resection and treatment, is reported. The histologic appearance of the primary neoplasm was identical to that seen in the biopsy specimens of the metastatic carcinoma involving the great toe and inguinal lymph nodes and to that of the residual neoplasm tissue found at necropsy. Electron microscopic examination of a lymph node metastasis demonstrated cytoplasmic microfilaments and numerous dense-core, peripheral, neurosecretory granules, as previously described in Merkel-cell carcinoma. Cytologic examination of a pleural fluid specimen demonstrated numerous small malignant cells closely resembling the cells seen in the histopathologic sections from the surgical and necropsy tissues involved by metastatic carcinoma. This is the first report of the cytologic findings in a patient with Merkel-cell carcinoma metastatic to the pleural cavity.

Carcinoma, Small Cell↗
PubMed2006

Primary neuroendocrine carcinoma of the vagina with Merkel cell carcinoma phenotype.

We describe a case of primary neuroendocrine carcinoma arising from the anterior vaginal wall of a 67-year-old woman. Primary neuroendocrine carcinoma of the vagina is a rare entity with only 25 previously reported cases in the literature. In previous reports, these tumors have not been distinguished from primary neuroendocrine carcinoma of the skin (Merkel cell carcinoma). The tumor was composed of cells that showed neuroendocrine-type nuclear features with hyperchromasia, nuclear molding, occasional small nucleoli, and a chromatin pattern that was finely granular. The tumor cells were positive for cytokeratin 20 (CK20), neuron specific enolase, pancytokeratin, epithelial membrane antigen, and chromogranin A expression. Ki-67, a marker of proliferation, was also positive in>90% of cells. The tumor cells showed intense expression of Bcl-2 oncoprotein and mild to moderate expression of c-KIT. Synaptophysin, neurofilament, CD45, CD56, CD10, S-100, HMB-45, cytokeratin 7, and thyroid transcription factor 1 were negative. This pattern of staining is consistent with a Merkel cell carcinoma. This is the first report of a primary neuroendocrine carcinoma of the vagina with a Merkel cell phenotype. Previous studies have not distinguished primary neuroendocrine carcinoma of the vagina from Merkel cell carcinoma of the skin. Positive expression of CK20 in primary small cell carcinoma of the vagina might represent a Merkel cell carcinoma subtype of this tumor.

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PubMed1981

Neuron-specific enolase in the Merkel cells of mammalian skin. The use of specific antibody as a simple and reliable histologic marker.

Merkel cells are specialized skin receptor cells, characterized by their particular location in the epidermis and close association with nerve terminals. Although they can be distinguished ultrastructurally by their small, electron-dense secretory granules, there is no specific and reliable method for identifying them by light microscopy. Using antibodies to neuron-specific enolase (NSE), the authors have shown sparsely distributed groups of specifically immunostained cells and associated nerve terminals in the nose skin of cats and rats. These cells were easily distinguished from other epithelial cell types, including melanocytes and Langerhans cells and had all the morphologic features of Merkel cells and their so-called neurite complexes, including the characteristic cytoplasmic secretory granules (60 nm in diameter). NSE immunostaining is a simple and reliable method for the specific light-microscopic staining of Merkel cells and provides further evidence for NSE as a marker for the diffuse neuroendocrine system.

Animals↗
PubMed1997

Primary cutaneous neuroendocrine (Merkel cell) carcinoma in association with squamous- and basal-cell carcinoma.

The co-existence of squamous-cell carcinoma (SCC) and neuroendocrine (Merkel cell) carcinoma (NEC) of the skin has been well documented in several patients. The concurrent development of NEC and basal-cell carcinoma (BCC) in the same cutaneous lesion, on the other hand, has not been reported. We describe a 68-year-old man presenting with NEC, SCC, and BCC arising at the same site in retroauricular skin. Cells of NEC and SCC showed an intermingled pattern of growth, whereas those of BCC were "embedded" among those of the other two tumors. Immunohistochemical stains were consistent with the histopathologic diagnosis. We believe that this is the first report of the association of NEC, SCC, and BCC in the same skin lesion.

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PubMed1996

[Merkel cell carcinoma: primary cutaneous neuroendocrine tumor].

Merkel cell carcinoma is a neuroendocrine primitive tumor of the skin. We report a case who develops node and visceral metastasis, and dead. The clinical presentation, diagnosis, histology, immunocytochemistry, treatment and prognosis of this tumor will be discussed.

Carcinoma, Merkel Cell↗
PubMedDate not supplied

Expression of erythropoietin receptor in human Merkel cell carcinoma of the eyelid.

BACKGROUND: Merkel cell carcinoma (MCC) of the eyelid is a rare malignant solid tumor of the elderly, which demonstrates a large, firm, reddish nodule mimicking an angiomatous lesion. The expression of erythropoietin (Epo) and Epo receptor (EpoR), as well as vascular endothelial growth factor (VEGF), VEGF receptor (VEGFR) and basic fibroblast growth factor (bFGF) were examined in human MCC tissues. MATERIALS AND METHODS: Three patients diagnosed with MCC of the eyelid underwent surgical excision. Isolated tissues were fixed by 4% paraformaldehyde and then were examined using immunohistochemistry. RESULTS: The carcinoma cells consisted of irregular tumor nests with linear stroma and showed hypercellularity indicated by small round nuclei with several mitoses. While immunoreactivity of Epo was undetectable, an increased expression of EpoR was noted in the carcinoma cells. Cytoplasmic immunoreactivity for EpoR was detected in a variety of carcinoma cells, including mitotic cells. VEGF, VEGFR, and bFGF, other angiogenic factors were not expressed in the MCC tissues. CONCLUSION: EpoR was highly expressed in MCC of the eyelid, suggesting that the Epo-EpoR pathway plays an important role in the formation of MCC.

Carcinoma, Merkel Cell↗
PubMed1998

Merkel cell carcinoma of the abdominal wall.

Merkel cell carcinoma is a rare highly malignant tumour. There have been previous descriptions of the CT appearances of this tumour, but to our knowledge this is the first MRI description. MRI may be a more sensitive method of initial evaluation of the local extension of the primary tumour.

Abdominal Muscles↗
PubMed1987

Merkel cell mitoses in vibrissae: an ultrastructural study.

This is the first ultrastructural description of Merkel cell mitoses. We observed four mitotic cells showing dense cored membrane-bound granules within their cytoplasm, i.e. the unique ultrastructural characteristics of Merkel cells which are not shared by other cutaneous epithelial cell types. These cells were located in vibrissal hair follicles of 12, 13 and 14 days old mouse embryos. This finding indicates that proliferation of Merkel cells can take place in the skin.

Animals↗
PubMed1997

Pharmacokinetics of carboplatin and etoposide in a haemodialysis patient with Merkel-cell carcinoma.

We present a Merkel-cell carcinoma patient with chronic renal failure requiring haemodialysis and evaluate the pharmacokinetics of carboplatin and etoposide during haemodialysis. The area under the concentration-time curve of carboplatin was increased by prolonging the interval between administration and haemodialysis. However, that of etoposide was not changed. Carboplatin showed good membrane permeability in haemodialysis, while etoposide showed no permeability. In conclusion, the pharmacokinetics of carboplatin could be controlled by haemodialysis and the interval between chemotherapy and haemodialysis. However, the pharmacokinetics of etoposide were not affected.

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PubMed1996

Merkel cell tumour occurring simultaneously in the upper and lower eyelids.

PURPOSE: To highlight an unusual presentation of two Merkel cell tumours in the same patient. RESULT: We report a case of two Merkel cell tumours occurring simultaneously in the upper and lower eyelids of an elderly woman, a unique occurrence. Wide local resection and reconstruction resulted in microscopic clearance of the tumours. Lymphatic spread was detected, a common feature. She had previously undergone excision of a similar lesion from the lower eyelid. CONCLUSION: Merkel cell tumour is a rare tumour of the elderly that often locally recurs and metastaseses early. Treatment consists of wide local excision with or without adjuvant radiotherapy. Juxtaposing lesions on the eyelids have not been previously reported. We postulate that this patient showed local recurrence and a new tumour of the upper eyelid simultaneously.

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PubMed2005

[Merkel cell carcinoma. Study of five cases].

Merkel cell carcinoma (MCC) is a rare malignant skin tumor of neuroendocrine origin with a poor prognosis and rapid progression. It is usually an erythematous nodule on the face, and is associated with other skin neoplasms. Its histology shows a large mass of small cells containing oval nuclei with powdery chromatin in the dermis. These cells are positive for neurospecific enolase, chromogranin, synaptophysin and cytokeratins AE1/AE3. We present five patients (3 males and 2 females, aged 58 to 89 years) seen at our hospital in the last three years for MCC. Their treatment and evolution were tracked, and many of the aspects indicated were seen. MCC must be kept in mind in the differential diagnosis, as early detection along with aggressive treatment significantly improve the patients survival rate. Close follow up is necessary because of the high recurrence rates. The development of a response protocol in order to better manage this disease would be desirable.

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