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PubMed1986

Merkel cell tumor: diagnosis, prognosis, and management.

The histologic features of the Merkel cell and the pathologic characteristics of the Merkel cell tumor are described. From a literature review, 68 cases are examined; 23 cases that have been followed up accurately are presented from the Mayo Clinic. A representative case is used to demonstrate the problems of diagnosis and suggested treatment. The latter should be wide local resection with removal of nodal metastases if present. When indicated, this should be followed up with radiation therapy. Chemotherapy is of little or no value. Survival rates are presented.

Adenocarcinoma↗
PubMed2001

Merkel cell carcinoma (neuroendocrine carcinoma of the skin).

We review the literature on Merkel cell carcinoma (MCC; primary neuroendocrine carcinoma of the skin) and add 36 cases to the over 800 already described in the literature. Though generally considered a tumor of the elderly, MCC can also occur in young patients. Microscopically, there are dermal proliferations of small cells possessing nuclei with finely dispersed chromatin. The occasional presence of squamous or eccrine differentiation suggests a pluripotential stem cell origin. Immunohistochemistry is of great help in distinguishing these tumors from potential mimics such as malignant melanoma, lymphoma, or metastatic small cell (neuroendocrine) carcinomas. Recent chromosomal studies have enhanced our understanding of the biology of these tumors. Despite the high metastatic rate associated with Merkel cell carcinoma, spontaneous regression has been reported, and there have been some therapeutic successes. The high survival rate for stage I lesions indicates the importance of early recognition and treatment of these tumors.

Carcinoma, Merkel Cell↗
PubMedDate not supplied

Merkel cell carcinoma: an aggressive neoplasm.

This article presents a rare case of Merkel cell carcinoma (MCC) of the skin. This tumor is also known as trabecular carcinoma or cutaneous small cell undifferentiated carcinoma (CSCUC). This patient had a palpable non-tender mass in her right upper thigh and a large palpable lymph node in the right inguinal area. Microscopic examination revealed Merkel cell carcinoma (MCC) in the skin of the upper thigh as well as in the inguinal lymph node. Immunoperoxidase stains confirmed the diagnosis. Due to its aggressiveness and very unfavorable prognosis, prompt diagnosis and adequate treatment are essential. Wide local excision with adequate margins followed by radiation therapy is the treatment of choice.

Aged↗
PubMed1987

Staining of neuroendocrine Merkel cells of human epidermis using the uranaffin reaction.

The uranaffin reaction (UR) stains neurosecretory (NS) granules of the neuroendocrine system under certain experimental conditions of staining and rinsing solutions. Human normal neuroendocrine (NE) Merkel cells stained using the UR exhibit a positive reaction in their NS granules, ribosomes, and nuclear chromatin. The average values of maximum granular diameter (GD = 69.1 nm) and area (GA = 3637.8 mm2) of NS granules measured in the adult NE Merkel cells stained with UR are significantly greater than those (GD = 61.4 nm; GA = 2699.8 nm2) seen in the fetal NE Merkel cells also stained with UR. No differences in form factor are found between fetal and adult NS granules. On different samples of human adult and fetal epidermis it is demonstrated that UR is a useful cytochemical marker for the NS granules of normal NE Merkel cells.

Adult↗
PubMed1991

Fine-needle aspiration cytology of a metastatic Merkel-cell carcinoma.

The cytologic features of Merkel-cell carcinoma metastatic to inguinal lymph nodes are described. The primary tumor was in the buttocks. The cytologic smears from the inguinal lymph node were highly cellular, with small to medium-sized cells in a predominantly discohesive or single-cell pattern, as well as large clusters surrounding segments of capillary-sized blood vessels. The nuclei were uniform, round to oval, with delicate nuclear membranes. The chromatin pattern was fine and "powdery" with multiple small micronucleoli. The cytoplasm was very scanty. Intermediate filament "buttons" were abundant. Rosette formation was very rare. Frequent mitotic figures and individual cell necrosis were observed. These features are helpful in the differential diagnosis from other small-cell tumors that may involve the skin.

Aged↗
PubMed1992

Serotonin-like immunoreactivity in Merkel cells and their afferent neurons in touch domes from the hairy skin of rats.

Immunoreactivity to serotonin was observed in Merkel cells as well as the afferent type I nerves terminating upon them in touch domes excised from the belly skin of rats. Type I nerves were strongly immunoreactive and could be traced through the dermis of the domal papilla. Merkel cell immunoreactivity was sometimes seen in the entire cell, but was often localized in the Merkel cell cytoplasm adjacent to nerve terminals and may have been in the terminals themselves. Domes were fixed by immersion in 4% paraformaldehyde-lysine-sodium-m-periodate (PLP) fixative at 4 degrees C for 2.5-3 hours and cryoprotected in 30% sucrose overnight. Sections were processed with the avidin-biotin complex peroxidase (ABC), peroxidase-antiperoxidase (PAP), and indirect immunofluorescence techniques with rabbit antiserum generated against serotonin.

Afferent Pathways↗
PubMed1999

Expression of the apoptosis-related oncogenes bcl-2, bax, and p53 in Merkel cell carcinoma: can they predict treatment response and clinical outcome?

Chemotherapy and radiation therapy act predominantly through the induction of apoptosis in malignancies. Merkel cell carcinoma, an aggressive malignancy with prominent apoptosis, has proved to be sensitive to both modes to a certain degree. We used immunohistochemical methods to examine 25 Merkel cell carcinomas and 8 of their lymph node metastases to assess the status of the antiapoptotic gene bcl-2 and 2 proapoptotic genes, wild-type p53 and bax. All tumors showed prominent bax immunopositivity; 76% were positive for bcl-2, and only 28% were positive for p53, the latter presumably reflecting mutated p53. No statistically significant relationship was found between tumor immunopositivity and therapy response or survival. The widespread bax immunopositivity and the apparently low rate of p53 mutations, as suggested by the low rate of p53 immunopositivity, may be related to the presence of prominent apoptosis in Merkel cell carcinoma. The finding of bcl-2 immunopositivity in 76% of the tumors suggests that some of the tumor cells may be resistant to apoptosis-inducing agents.

Adult↗
PubMed1999

Merkel cell carcinoma of the lower lip: a case report and histopathologic study.

Merkel cell carcinoma of the lower lip is a rare clinical entity. It is generally thought to be more aggressive than the more common skin cancers of the lips and oral cavity. The literature reveals that delayed diagnoses and poor survival are common among patients with these malignancies. Recommended treatment is surgical excision with wide margins and treatment of cervical metastases with either surgery or radiotherapy or both. Unlike other malignant neoplasms, the occurrence of Merkel cell carcinoma in a relatively older population makes comorbid conditions a key factor in treatment planning.

Aged↗
PubMed2005

Merkel cell tumor: report of two cases and review of the literature.

The "Merkel cell carcinoma" is a rare tumor usually occuring in the sun-exposed skin. Its poor prognosis is explained by a high rate of metastasis (one third of the patients at the initial presentation) and a high post-operative recurrence rate. Descriptions of the imaging features of this type of tumor are rare. We present two cases of Merkel cell carcinoma localized to the head region. In the first patient, the lesion involved the soft tissues of the scalp with secondary invasion of the skull and meninges. The second patient had a metastasis to the parietal lobe.

Aged↗
PubMed1995

Cutaneous lymphoma-simulating Merkel cell carcinoma-molecular genetic demonstration of a clonal disease with divergent immunophenotypes.

Merkel cell carcinoma and malignant lymphoma are important differential diagnoses for undifferentiated cutaneous round cell tumors and immunohistochemistry is instrumental in their evaluation. We describe a case of a 73-year-old man who had cutaneous large cell lymphoma in the right leg (immunophenotype CD45+, CD19+, CD20+ CD22+, lambda clonal, cytokeratin-, NSE-) and lymphoma in left leg simulating Merkel cell carcinoma showing absence of leukocyte antigens (CD45-, CD20-, no light chains) and focal expression of keratin and NSE. However, analysis of polymerase chain reaction amplification products of DNA extracted from both lesions showed two amplifiable sharp bands indicating clonal rearrangements of both alleles of the immunoglobulin heavy chain. Cloning and sequencing of the products from left and right leg lesions showed either 100% homology (one band), or close similarity (the other band), indicating that both tumors were derived from the same B-cell lymphoma clone. This case shows the value of polymerase chain reaction and sequencing in analyzing the ultimate nature of lymphoproliferations and illustrates the potential limitations of immunophenotyping.

Aged↗
PubMed1995

Aspiration cytodiagnosis of metastatic Merkel-cell carcinoma.

A case of metastatic Merkel-cell carcinoma to lymph nodes on the left side of the neck and left parotid is described. The primary was at the left side of the cheek and bridge of the nose. The cytologic features in needle aspirates of metastases included increased cellularity, discohesive or loose groups of small-to-medium size malignant cells with uniform, round-to-oval nuclei, delicate nuclear membranes, fine chromatin, multiple micronucleoli, and scanty cytoplasm. Additionally, rare intermediate filament "buttons" and frequent mitotic figures were found. The primary tumour showed similar features. On immunostaining, although a positivity for chromogranin was noted in the primary tumour, it was found to be negative in the cytologic material. All other histochemical and immunostains were found to be negative in both the primary and metastatic neoplasm. The problems in differential diagnosis from other small cell tumours and the features of this unique tumour that may be helpful in the diagnosis are discussed.

Aged↗
PubMed2006

Merkel cell carcinoma of the tongue and head and neck oral mucosal sites.

Merkel cell carcinoma (MCC) is an uncommon primarily dermal malignancy of relatively aggressive biologic course. Several presentations in the mucosa of the head and neck region have been reported in the literature, and 3 such patients have recently been seen at our institution. We review this recent experience and present the first reported primary lingual MCC in a 57-year-old caucasian man. We provide a review of oral mucosal MCC and guidelines for histopathologic and immunohistochemical diagnosis. Merkel cell carcinoma should be included in the differential diagnosis of head and neck mucosal lesions, especially if the tumor is submucosal, and MCC may involve the tongue. Mucosal MCC is aggressive, and there is a high risk for local recurrence and regional and distant metastasis. Fulminating courses are often seen. We discuss our treatment policies based on the current literature.

Aged, 80 and over↗
PubMed1994

Merkel cells and prurigo nodularis.

BACKGROUND: Increased numbers of dermal nerves have been demonstrated in prurigo nodularis and have been theoretically linked to the intense pruritus. We hypothesized that the neuronal proliferation in prurigo nodularis might be associated with an increased density of Merkel cells because they are also a component of the neurocutaneous system. METHODS: We examined skin biopsy specimens from 20 cases of prurigo nodularis for Merkel cells with the use of a standard immunohistochemical assay (avidin-biotin-peroxidase complex system) with an antibody to cytokeratin 8 (CAM 5.2). Six cases of lichen simplex chronicus were examined as controls. RESULTS: Merkel cells were present in the interfollicular area of the basal cell layer in 15 (75%) of 20 prurigo nodularis cases and in one (17%) of six cases of lichen simplex chronicus. CONCLUSION: Merkel cells are increased in number in prurigo nodularis and may be a component of the neurocutaneous abnormality associated with this disorder.

Humans↗
PubMed1992

A case of Merkel-cell carcinoma metastatic to the tonsil.

Metastatic tumours are rare in the tonsil. We describe a 69-year-old male patient who had previously undergone a resection of a Merkel-cell tumour of the left forearm and subsequently presented with a left tonsillar tumour. Biopsy revealed a metastatic Merkel-cell carcinoma. Our patient is the first described case of Merkel-cell carcinoma metastasizing to the tonsil. The clinical and histopathological picture of this rare tumour is presented, along with a review of literature.

Aged↗
PubMedDate not supplied

Merkel cell carcinoma of the ear.

All the consultants agree that, given this patient's history, a common skin tumor like squamous cell or basal cell carcinoma is unlikely. Melanoma or Merkel cell carcinoma belong in the differential. Interestingly, the consultants all suggest a biopsy of the lesion prior to other testing, and because this tumor is so accessible, a biopsy should not interfere with further testing or treatment. Drs. Weymuller and Marks would then proceed with a CT scan; Dr. Ridge favors an MRI scan. While a chest-ray is in order to rule out metastases, Dr. Weymuller also suggests immunocytochemistry. All the experts agree that the primary tumor should be excised. Dr. Weymuller would perform a total parotidectomy with facial nerve preservation, while Drs. Marks and Ridge suggest a superficial parotidectomy with facial nerve preservation. Drs. Weymuller and Ridge would also perform a modified radical neck dissection. In the absence of cervical disease, Dr. Marks would treat the neck primarily with radiotherapy. Only Dr. Weymuller favors immediate reconstruction and would use a lower trapezius island flap or a large rotational flap. Drs. Marks and Ridge prefer primary closure or skin graft. Drs. Weymuller and Ridge would treat this patient with combined therapy, giving radiotherapy to the primary area and the neck postoperatively at a dose of 55-60 Gy. However, Dr. Marks would treat the primary site postoperatively and the neck primarily with radiotherapy. He would treat the primary site with 59.40 Gy and the neck with 50.40 Gy.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1999

Merkel cell carcinoma and chronic arsenicism.

Arsenic is a well-documented human carcinogen. Bowen's disease, squamous cell carcinoma, and basal cell carcinoma are the most common skin cancers found in patients exposed to arsenic over the long term. Merkel cell carcinoma has been documented in Taiwanese patients who resided in an endemic area of black foot disease, another condition found in patients with chronic arsenicism. We collected all cases of Merkel cell carcinoma diagnosed at two medical centers in Taiwan (N = 11) to find a possible association between chronic arsenicism and Merkel cell carcinoma. In our study 6 of the 11 patients were residents of the endemic areas for chronic arsenicism.

Aged↗
PubMed1991

Merkel cell tumour: clinical behaviour and treatment.

We have reviewed 30 reports of Merkel cell tumour and described a further five cases in order to establish a database and from this more clearly define the biology of this tumour, prognostic factors that govern outcome, and optimal management. After excision alone of the primary lesion, local recurrence occurred in 39 per cent of patients and regional failure occurred in 46 per cent. In contrast, in patients treated by excision plus prophylactic treatment (adjuvant node dissection and/or adjuvant radiation), local recurrence occurred in 26 per cent and regional failure in 22 per cent. Locoregional recurrence carried an ominous significance with 67 per cent of patients subsequently dying of the disease. For patients who either presented with regional disease or later developed regional disease, the best outcome (44 per cent survival with mean follow-up of 40 months) was obtained following treatment by therapeutic node dissection with or without radiation. In contrast, treatment of regional disease with radiation alone was associated with only a 20 per cent survival rate. Unfavourable prognostic factors included young age, lesions sited in the head and neck or trunk, male sex, and the presence of locoregional failure and/or systemic disease. We conclude that Merkel cell tumours behave in a similar manner to the aggressive variants of melanoma and that minimal treatment consists of wide surgical resection of the primary lesion (with a margin of 2.5-3 cm) coupled with resection and probably also radiation of regional disease if present. In addition, consideration should be given to prophylactic node dissection in node negative patients, especially in those patients with unfavourable prognostic factors.

Adult↗