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PubMed1991

Anatomical mapping of Merkel cells in normal human adult epidermis.

The distribution of Merkel cells (MCs) in normal human skin and mucosa was studied using the mouse monoclonal antibody Troma-1, reacting specifically with component 8 of the Moll cytokeratin catalogue. The specificity of this antibody for MCs in human skin was assessed by double indirect immunofluorescence (IIF) and immunoelectron microscopy. Two-hundred and thirty 6-mm punch biopsies were obtained from 44 different sites from six human cadavers within 48 h post-mortem. IIF was performed with Troma-1 on EDTA-split epithelial sheets and the MCs were counted and the mean values per mm2 calculated for each site. Regions with greater than 50 MC/mm2 were the lips, hard palate, palms, finger pads, proximal nail fold, and dorsum of the feet. Three different patterns were observed in the epidermis or mucosa: MCs grouped in clumps, linear and arciform arrangements, and scattered MCs. In the hair follicles grouped MCs were observed in the bulb and scattered MCs were seen in the outer root sheath.

Adult↗
PubMed1983

Merkel cell carcinoma: a malignant neuroendocrine tumour of the eyelid.

Merkel cell carcinoma is a recently described tumour which may occur on the face of the elderly. We report such a lesion which presented as a cyst on the eyelid of an 88-year-old woman. This tumour differs from other tumours of the eyelids in its propensity for local and distant spread.

Aged↗
PubMed1986

[Merkel-cell tumor of the upper lip].

A case of Merkel cell tumor is reported. Generally localized in the dermis of the cervicofacial region, this case of a tumor involving the labial mucosa is unique. Clinical and histologic characteristics of this rare clinicopathologic entity are summarized.

Aged↗
PubMed1984

[Neuroendocrine (Merkel cell) carcinoma of the skin].

A case of neuroendocrine Merkel cell carcinoma of the skin in a 65-year-old female patient is reported. The definite diagnosis can be established only by ultrastructural and immunohistochemical investigations. Characteristic features are cytoplasmic neurosecretory granules and the identification of neuron-specific enolase.

Aged↗
PubMedDate not supplied

Merkel cell carcinoma: a case series of twelve patients and review of the literature.

BACKGROUND: Merkel cell carcinoma (MCC) is a rare tumor of the skin. MATERIALS AND METHODS: A retrospective analysis of 12 cases of MCC diagnosed and treated over a 14-year period. RESULTS: Seven females and 5 males, with a median age of 72 years and MCC of the face (5), trunk (1) and extremities (6), were studied. The stage was I in 2 cases and II in 10. Eight patients had surgery, two surgery and chemotherapy and two chemotherapy only. The last two patients died of disease after 10 and 16 months. Three patients suffered locoregional recurrence after 4, 6 and 24 months and three were lost to follow-up after 8, 9 and 24 months while disease-free. Two disease-free patients died of unrelated causes after 4 and 48 months, while three were alive and well after 24, 48 and 84 months. The three relapsing patients received chemotherapy in addition to local radiation in one case. One is alive and well, the other alive with disease and the third died of disease after 84, 107 and 10 months, respectively. CONCLUSION: MCC often recurs locally. Surgery is the treatment of choice, while radiotherapy is important for local control. Chemotherapy produces responses in the neoadjuvant setting or after relapse.

Aged↗
PubMed1983

Merkel cell carcinoma: a report of three cases with neurone-specific enolase activity.

Three cases are described of a primary cutaneous neoplasm occurring in elderly patients, histological and immunohistochemical features of which support an origin from Merkel cells. Microscopically sheets of uniform small cells filled the dermis, often with a prominent trabecular pattern. Ultrastructurally the cells showed neurosecretory granules, tangles of microfilaments, scattered mitochondria and occasional intranuclear rodlets. Immunohistochemical staining for neurone-specific enolase was positive and for prekeratin was negative in each case. The definitive diagnosis of Merkel cell tumour can be made with a combination of electron microscopy and immunohistochemistry.

Adenocarcinoma↗
PubMed2000

Two cases of merkel cell tumour arising in patients with chronic lymphocytic leukaemia.

Chronic lymphocytic leukaemia (CLL) has been associated with an increased incidence of second neoplasms, especially skin cancers such as basal and squamous cell carcinomas. No association with the rarer skin cancer, the Merkel cell tumour (MCT), has previously been reported. Two patients with MCT had a previous diagnosis of CLL. MCT is an aggressive skin cancer, as up to 45% of patients have lymph node involvement at presentation and 5-year disease-free survival is as low as 30%. It is most commonly found on sun-exposed areas of the body, and ultraviolet radiation together with drug-induced or CLL-induced immunosuppression may be the underlying mechanism in the observed relationship between CLL and other skin cancers.

Aged↗
PubMed1977

On the occurrence of Merkel cells in the epidermis of teleost fishes.

The ultrastructure of a differentiated cell type in the epidermis of two species of teleost fish, Ictalurus melas and Phoxinus phoxinus, is described. This cell type has a synaptic association with nerve fibres, microvillus-like peripheral processes, and membrane-bounded inclusions, which together are the diagnostic features of the Merkel cells of tetrapod vertebrates. Other cytoplasmic features are shared with the epithelial cells. The appearance of the membrane-bounded granules depends on the fixative used; after fixation with glutaraldehyde the granules are of a size and electron-density comparable to that found in tetrapod Merkel cells, but after fixing in osmium tetroxide the granules are inconspicuous.

Animals↗
PubMed1990

Merkel cell carcinoma: the clinical course.

Merkel first discovered the cells named after him in the snout skin of voles in 1875. These cells are thought to originate from the neural crest and act as mechanoreceptors. When they have undergone malignant change, the neurosecretory granules in the cytoplasm may release various polypeptides, suggesting that the tumor is an APUDoma. In a computer search of the literature 121 cases were identified. It was revealed that the most common lesion is an erythematous nodule arising in the face or lower limb and occurring predominantly in women in their late 60s. The regional nodes became involved in half the patients, and the three-year survival was approximately 60%. Two unusual cases, in women 72 and 73 years old respectively, with metastasizing lesions that responded to a combination of surgery and radiotherapy are reported, and the literature is discussed.

Aged↗
PubMedDate not supplied

[Molecular characterization of cutaneous neuroendocrine (Merkel cell) carcinoma. Review of the literature and presentation of a caseload].

Molecular characterization of neuroendocrine (Merkel cell) carcinoma of the skin. Review of the literature and report of three cases. Although neuroendocrine carcinoma of the skin (NECS) is comparatively a rare clinical-histological entity, numerous morphological and ultrastructural studies have been carried out since the tumor was identificated by Toker (1972). Recently immunocytochemistry has allowed a better molecular characterization (immunophenotype) of this tumor and a more exact diagnosis. The main problem for the pathologist is the differential diagnosis between NECS and skin neoplasms--both primitive and metastatic--which require a more aggressive treatment. Often the classical morphological criteria do not distinguish NECS from non-Hodgkin's lymphoma, amelanotic melanomas, cutaneous metastases of lung small cell carcinoma or of neuroblastoma. The co-expression of cytokeratins and neurofilaments constantly found in NECS, is surely the best differential criterion from non-neuroendocrine carcinomas. Furthermore, the typical paranuclear location of both the intermediate filaments in NECS is a distinctive peculiarity as opposed to lung microcytoma, where cytokeratins and neurofilaments, when present, show widespread perinuclear positivity. Chromogranin A is found only in a small percentage of tumor cells, whilst synthesis of calcitonin, somatostatin, gastrin, ACTH, is very rare. Finally, the lack of common leukocyte antigen (CLA), S-100 protein and vimentin in NECS rules out the diagnoses of lymphoma, melanoma and sarcoma respectively.

Aged↗
PubMed1992

Multiple hamartoma syndrome (Cowden's disease) associated with renal cell carcinoma and primary neuroendocrine carcinoma of the skin (Merkel cell carcinoma).

A case of multiple hamartoma syndrome (Cowden's disease) associated with renal cell adenocarcinoma and primary neuroendocrine carcinoma of the skin is described. Neither of these neoplasms has been documented previously in association with this genodermatosis. A search for epidermal growth factor receptor (c-erb-B protooncogene) gene abnormalities in the kidney, liver, and thyroid, as well as in tissue of the primary neuroendocrine carcinoma, was negative. Serum obtained from the patient before his death contained elevated levels of both chromogranin A (2641 ng/mL; normal level, less than 20 ng/mL) and calcitonin (517 pg/mL; normal level, less than 200 pg/mL), suggesting that the patient's principal tumor was neuroendocrine in origin.

Aged↗
PubMedDate not supplied

Merkel cell carcinoma of the head and neck region: report of two cases.

Two cases of Merkel cell carcinoma (MCC) of the head and neck region are reported in order to stress their diversity in morphological, immunohistochemical and clinical findings. The remarkable variability of MCC has been analyzed, particularly in relation to the differential diagnosis and prognostic implications.

Aged↗
PubMed1977

["Pagetoid reticulosis" (Woringer and Kolopp disease). A disease of the Merkel cell (author's transl)].

A case of Woringer and Kolopp disease "Pagetoid reticulosis" is described. Clinical features include a ring of a target pattern of erythemato-squamous infiltrated skin lesion. The characteristic histological aspect of dense epidermal infiltrate by abnormal cells with a spared dermis has been observed. Ultrastructural findings include cytoplasmic granules with a found electron dense core and close relationship to neurites, two features of the Merkel cell of human normal epidermis. By comparing our patients with the already reported cases of Woringer and Kolopp disease it seems likely that this is a unique disease with no relationship with cutaneous lymphoma but which is defined by a Merkel cell proliferation.

Aged↗
PubMed2004

Complete remission of Merkel cell carcinoma of the scalp with local and regional metastases after topical treatment with dinitrochlorbenzol.

Merkel cell carcinoma (MCC) is a highly aggressive tumor with a high percentage of recurrence, metastatic spread, and mortality. Treatment of metastasized MCC is not standardized and prognosis of metastasized MCC is often poor. Current protocols recommend surgery, adjuvant radiation therapy, and often lymph node dissection to prevent recurrences. A few sporadic reports of spontaneous regression of MCC suggest a so far not yet characterized role and potential of the immune system in controlling this tumor. We describe a 69-year-old man with extended inoperable MCC of the scalp including multiple local and regional metastases who responded with complete remission to 4 weekly treatments of topically applied immune-modulating dinitrochlorbenzol. Together with subsequent irradiation, remission has now lasted for more than 1 year.

Adjuvants, Immunologic↗
PubMed1995

The importance of postoperative radiation therapy in the treatment of Merkel cell carcinoma.

PURPOSE: To determine the role of postoperative radiation therapy in the treatment of Merkel cell carcinoma (MCC). METHODS AND MATERIALS: Eighty patients with MCC of the skin were treated with curative intent at the Queensland Radium Institute between 1981 and 1991. Fifty-one patients (63.7%) were referred after initial biopsy for further treatment and 29 patients (36.3%) were referred with locally recurrent disease following primary surgery elsewhere. Thirteen patients (16.3%) presented with nodal disease without a clinically definable primary skin lesion. RESULTS: Of the 80 patients, 38 had undergone surgery (S) alone, 34 surgery plus radiotherapy (S + RT), 7 RT after incomplete S, and 1 patient had chemotherapy (CT) plus RT. Overall survival at 36 months for all patients was 68%. All of the 38 patients treated with S alone relapsed. The median time to recurrence was 5.5 months. Ten of the 34 patients treated with S + RT relapsed. The median time to recurrence was 16.5 months. Of the 80 patients, 55 have relapsed after primary treatment, 25 have developed systemic metastases, and 26 patients have died as a direct result of MCC. CONCLUSION: Our large series confirms earlier reports from this Institute and highlights the importance of S + RT over S alone in preventing local recurrence of this highly malignant skin cancer.

Adult↗
PubMed2005

Clinicopathological and immunohistochemical analysis of 20 cases of Merkel cell carcinoma in search of prognostic markers.

AIMS: To evaluate the clinicopathological and immunohistochemical characteristics of Merkel cell carcinoma (MCC) in an attempt to find new, potentially significant, prognostic markers. METHODS AND RESULTS: Clinical data and follow-up, histopathological features (pattern, cell size, thickness, mitoses, vascular invasion, lymphocytic infiltration) and immunohistochemical detection [CK20, thyroid transcription factor (TTF-1), chromogranin A, synaptophysin, p53, Ki67, Fli-1, CD99, c-Kit] were evaluated in 20 cases of MCC. Fli-1 and CD99 were detected in 90% and 55% of cases, respectively. Tumour size>30 mm, stage II, 'absent' lymphocytic infiltration, and the presence of>50% of Ki67+ tumour cells, were found to be prognostic indicators of disease-free interval (DFI), but only 'absent' lymphocytic infiltration constituted an independent prognostic factor of DFI after multivariate analysis. For overall survival, the same variables, together with local recurrence and lymph node involvement, had prognostic significance, with only local recurrence as an independent prognostic factor after multivariate analysis. CONCLUSIONS: Absence of lymphocytic infiltration and Ki67 immunoreactivity in more than 50% of tumour cells should be evaluated in conjunction with other well-known prognostic markers in MCC. Furthermore, recognizing that Fli-1 and CD99 expression is commonly found in MCC by immunohistochemistry may avoid misinterpretation in the differential diagnosis of MCC with other small round cell tumours.

12E7 Antigen↗