Merkel cell tumor of the head and neck. Five new cases with literature review

Avelumab as an Emerging Therapy for Eyelid and Periocular Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is a highly aggressive cutaneous malignancy, with a high metastasis rate and a significant proportion of cases affecting the eyelid or periocular region. Current treatments for periocular MCC include wide local excision (WLE) with or without adjuvant radiotherapy and can result in profound morbidity and visual deficit. Metastatic disease has been traditionally treated with chemotherapy, though durable responses are typically poor and toxicity is high. Avelumab (Bavencio®, Merck KgaA, Darmstadt, Germany and Pfizer Inc., New York, NY, USA), the first FDA-approved human anti-programmed death-ligand 1 (PD-L1) antibody for the treatment of metastatic MCC (mMCC), has demonstrated safety and efficacy as first-line treatment and in chemotherapy-refractory cases. This review summarizes pivotal clinical trial data for avelumab in the treatment of mMCC, including efficacy, safety and tolerability, and describes the efficacy of two other immune checkpoint inhibitors, pembrolizumab (Keytruda®, Merck & Co., Inc., Kenilworth, NJ, USA) and nivolumab (Opdivo®, Bristol‐Myers Squibb, New York, NY, USA and Ono Pharmaceuticals, Trenton, NJ, USA) for the treatment of advanced MCC. Our purpose is to provide the rationale to further investigate avelumab as a potential therapy for advanced or metastatic eyelid and periocular MCC.

Merkel cell carcinoma of the forehead area: a literature review and case report

BACKGROUND

Merkel cell carcinoma (MCC) is an uncommon, aggressive malignancy of the skin, mostly affecting head and neck area in elderly white patients. Between head/neck sites, face accounts for 61% and forehead accounts for 17% of all face MCCs.

PURPOSE

We here present a literature review MCC cases arising in the forehead area, published in the English literature in the period 1987-2018, and report a personal observation with a late diagnosis and a treatment out of the current recommendations. The aims of this paper are to provide an up-to-date on MCC arising in the forehead area and to raise awareness about misdiagnosis of this type of lesion mimicking arteriovenous malformations (AVM).

MATERIAL AND METHOD

Literature review was performed on PubMed and Medline database and "Merkel cell carcinoma (MCC)," "forehead" and "MCC forehead location" were the terms the authors searched for. Patients' data have been drawn from descriptions of single cases and of short case series reports. For each case, data were collected about clinical characteristics, treatment modalities and outcomes. The study has been limited to the clinical features of the disease, excluding etiologic/pathogenic aspects.

RESULTS

Twenty-five patients with forehead MCC have been identified, coming from 20 sources. Nineteen presented a locoregional disease and 6 had an advanced pathology. TNM classification was reported in only two cases lacking for the other available data. Patients presented at mean age of 66 years with solitary or multiple nodules or dome-shaped/hemispherical mass, rarely ulcerated. Mean size of tumors was 1.13 cm of max diameter. Previous or concurrent malignancies or immune-hematologic disorders (AIDS) were often associated. At first investigation, lesion was often mistaken for other malignant or benign processes and, then, diagnosis was generally late. Some type of preoperative biopsy was performed in 3 patients, while the others had only a postoperative microscopic study of specimen. Initial treatment consisted in 6 cases (24%) in a not further specified about extent and width of margins local excision of the primary lesion, while a wide resection was reported in only 3 cases (12%). Surgical treatment of involved lymph-nodes was performed in 3 cases (12%). Six patients underwent radiotherapy for locoregional or distant recurrences. Mortality and overall survival rate at five years were 28% and 24%, respectively. Spontaneous regression was observed in 3 patients (12%).

CASE REPORT

Personal observation concerned an 82-year-old woman presenting with a forehead periorbital 5 × 5 cm red-bluish mass. The erythematous lesion was erroneously diagnosed as hemangioma on the base of color, the absence of any signs of malignancy, an angio CT indicating a hypervascular tissue and a FNA cytology (FNAC) lacking of malignant cells. The mass was excised as a benign lesion with about 1 cm margins extent without searching larger edges. Postoperative radiotherapy was offered to the patient after histology report, but she refused. After 4 months from surgery, she had a parotid metastasis and died from the illness in spite of platinum-based chemotherapy.

CONCLUSIONS

This study confirms the aggressiveness of forehead MCC, comparable with that of other face similar tumors. Personal case suggests that the deceitful benign feature of lesion may mimic an AVM and that FNAC may be misleading and diagnostic failure worsen prognosis. Our experience suggests that in the face smaller than 2-3 cm margins resection may increase the risk of locoregional recurrence. Therefore, postoperative wide-field irradiation should be ever delivered, after forehead MCC surgery, not only when clear margins are unattainable or involved with tumor, but also when negative microscopic edges are documented and residual cancer is thought not persist in the tumor bed. Orbit irradiation seems to be not dangerous for the eye.

Lymph Node Merkel Cell Carcinoma with No Evidence of Cutaneous Tumor - Report of Two Cases

We report two cases of Merkel cell carcinoma within inguinal and axillary lymph nodes, respectively, showing no clinicopathologic evidence of a primary (extranodal) tumor; one of our patients was alive with no evidence of disease five years and ten months after the surgical excision of the neoplasm with no postoperative chemotherapy.

The diagnosis of nodal Merkel cell carcinoma needs to be supported by a careful immunohistochemical study: in fact, cytokeratin- and neurofilament-positive paranuclear “dots”, as well as epithelial antigens and neuroendocrine markers may be variably expressed in tumor cells, thus requiring the application of a complete antibody panel.

In the presence of a nodal Merkel cell tumor, an exhaustive clinico-radiologic search for a primary tumor must be carried out. After the exclusion of any reasonable starting point of the neoplasm, a provisional diagnosis of “primary” nodal Merkel cell carcinoma may be acceptable; since a primary extracutaneous tumor is expected to follow a less aggressive course than a metastatic one, follow-up data may provide indications as to the truly extracutaneous origin of Merkel cell carcinoma.

Merkel cell carcinoma of the eyelid and periocular region

Merkel cell carcinoma (MCC) in the eyelid and periocular region can be treated surgically, in most cases, with preservation of the eye and reasonable visual function. Adjuvant radiation therapy, sentinel lymph node biopsy, and chemotherapy should be considered for MCC of the eyelid and periocular region, especially for larger tumors that are T2b or more advanced and lesions that present with regional nodal or distant metastasis.

Unknown primary Merkel cell carcinoma: 23 new cases and a review

BACKGROUND

Knowledge is limited regarding unknown primary Merkel cell carcinoma (UPMCC).

OBJECTIVE

We sought to document the characteristics and behavior of UPMCC, and determine the most appropriate treatment.

METHODS

A multicenter, retrospective, consecutive study reviewing patients given a diagnosis of UPMCC between 1981 and 2008 was completed. In addition, a literature review of cases of UPMCC was performed.

RESULTS

In all, 23 patients with UPMCC are described and 34 cases from previous reports are compiled. Among the 23 new cases of UPMCC, the average age at diagnosis was 66.0 years; the majority of patients were male (87%) and Caucasian (100% of those reported). One patient was immunosuppressed, and 39% had a history of other cancer. After the initial biopsy, 16 patients had further evaluation of the involved lymph node basin. Half of these had additional positive nodes (8 of 16). The majority of patients had lymph node basin involvement only (78%), whereas 22% had lymph node basin and distant metastasis. The most common lymph node basin involved was inguinal. The median size of the involved lymph node at diagnosis was 5.0 cm. At 2 years, the overall survival of stage IIIB UPMCC was significantly improved versus stage IIIB known primary Merkel cell carcinoma (MCC): 76.9% to 36.4%.

LIMITATIONS

Limited number of cases and retrospective review are limitations.

CONCLUSION

Our data demonstrate improved overall survival in patients with stage IIIB UPMCC versus those with stage IIIB known primary MCC. Because of the unpredictable natural history of UPMCC, we recommend individualization of care based on the details of each patient's clinical presentation.

Merkel cell carcinoma with lymph node metastasis in the absence of a primary site: Case report and literature review

Merkel cell carcinoma (MCC) is a rare malignant skin neoplasm with the potential for local recurrence, spreading to regional lymph nodes (LNs) and distant metastases. Although it has been identified in various anatomical sites, LN metastatic MCC in the absence of a primary site is extremely rare. The present case reports a 54-year-old male who initially underwent histological examination of a biopsy specimen from the right inguinal LNs. A diagnosis of metastatic small cell carcinoma was made. Nine months later, this diagnosis was changed to MCC with multiple metastases following observation of a tumour mass in the right dorsal thigh. Additionally, in the present study a summary is provided of 23 published cases of MCC with initial LN metastasis in the absence of a primary site, with details of clinical characteristics, natural history and pertinent therapy of this uncommon tumour. The present patient with LN metastatic MCC in the absence of a primary site and the other reported cases demonstrate that although multimodal treatment with surgery, radiotherapy (RT) and chemotherapy provides excellent local control, local recurrence and distant metastases commonly develop in this uncommon tumour. LN metastatic MCC in the absence of a primary site is a highly malignant disease and the role of adjuvant postoperative RT and/or chemotherapy remains to be fully determined.

A comprehensive review of the treatment of Merkel cell carcinoma

Merkel cell carcinoma (MCC) is an uncommon but malignant cutaneous neuroendocrine carcinoma with a high incidence of local recurrence, regional lymph node metastases, and subsequent distant metastases. The etiology of MCC remains unknown. It usually occurs in sun-exposed areas in elderly people, many of whom have a history of other synchronous or metachronous sun-associated skin lesions. The outcome for most patients with MCC is generally poor. Surgery is the mainstay of treatment. The role of adjuvant therapy has been debated. However, data from recent development support a multimodality approach, including surgical excision of primary tumor with adequate margins and sentinel lymph node dissection followed by postoperative radiotherapy in most cases, as current choice of practice with better locoregional control and disease-free survival. Patients with regional nodal involvement or advanced disease should undergo nodal dissection followed by adjuvant radiotherapy and, perhaps, systemic platinum-based chemotherapy in most cases.

Merkel Cell Carcinoma of the Eyelid

PURPOSE

To evaluate the clinical and histopathologic characteristics of Merkel cell carcinoma (MCC) of the eyelid.

DESIGN

Retrospective case series and literature review.

PARTICIPANTS

Three consecutive patients with MCC of the eyelid who were referred to the Ocular Oncology Unit of Leiden University Medical Center, Netherlands.

METHODS

Clinical records and histopathologic material of patients with eyelid MCC were reviewed. The clinical presentation and treatment were evaluated.

MAIN OUTCOME MEASURES

Clinical and histopathologic description of eyelid MCC, with histologic proof of spontaneous regression of the tumor.

RESULTS

Three patients with MCC of the eyelid were included. Diagnosis was made by pathologic investigation and immunohistochemistry (S100, cytokeratin 20, epithelial membrane antigen, chromogranin). Two of the patients showed histologically proven complete spontaneous regression after nonradical excision of the tumor. After local excision, none of the MCCs demonstrated local recurrence, without regional or distant metastases. Mean clinical follow-up was 50 months.

CONCLUSIONS

Nonocular MCC is known to recur in 66% of patients and to be lethal in almost 33%. Merkel cell carcinoma of the eyelid is a rare malignancy that can not be recognized clinically. Clinical differential diagnosis must be made with a chalazion, and histopathologic differential diagnosis must be made with small cell carcinomas. Close follow-up of these patients is advised because of the potential high recurrence rate and lymphatic spread. The immunologic phenomenon of spontaneous regression points out the importance of the immune system in this disease.

Merkel cell carcinoma of the auricle

Merkel cell carcinoma is a rare malignant tumor of the skin. The face and extremities are the most common locations. We present a case of Merkel cell carcinoma of the auricle in a 93-year-old man subsequently treated with surgery and radiotherapy. The clinical features, prognosis, and treatment of the Merkel cell carcinoma are discussed.

Treatment of Recurrent Merkel Cell Carcinoma: An Analysis of 46 Cases

This report describes the course of recurrent Merkel cell carcinoma and defines possible treatment strategies for recurrent disease as seen in a long-term multisite retrospective analysis. Merkel cell carcinoma is a highly aggressive neuroendocrine skin cancer. Surgery and radiation therapy have been demonstrated ability to control this disease; however, recurrence is common. Systemic chemotherapy has, as yet, no presently defined role in primary treatment, and few conclusions can be reached regarding optimal treatment of disease recurrence. Forty-six patients were identified over the last 15 years in a retrospective analysis of patient records from several hospitals in the San Antonio, TX area. Hospital charts as well as outpatient treatment records were reviewed. Almost all patients developing recurrent disease did so within the first 2 years after primary treatment. Patients presenting distant disease had a median survival of 12 months, faring worse than those who display local or nodal disease. For patients with nodal or local recurrence, the mean survival after combination therapy (chemotherapy, radiation +/- surgery) was 36.5 months as compared with 17.5 months for those treated with a single modality (surgery or radiation or chemotherapy). The overall survival rate for the 46 patients with recurrence was 37%. Multimodality therapy has shown the best results for recurrent Merkel cell carcinoma thus far, and should be used if tolerated by the patient. Aggressive salvage surgery for local or nodal recurrence is encouraged, because this disease has a tendency to become more destructive upon recurrence. Adjuvant radiation therapy should also be used, if the patient has not exceeded their dose limitations. Disseminated disease, whether primary or recurrent, warrants further investigation in terms of optimal treatment.

Treatment of Merkel Cell Carcinoma

PURPOSE

The purpose of this study was to evaluate the treatment of Merkel cell carcinoma.

MATERIALS AND METHODS

We reviewed 85 cases of Merkel cell carcinoma. There were 68 males and 17 females. The majority of cases involved head and neck sites (48%), followed by the extremities (38%) and trunk (14%). Sixty-seven percent of the patients had stage I disease that was localized to the skin of origin at presentation. Twenty-five percent and 8% were stage II (nodal metastasis) and stage III (distant metastasis), respectively. Surgical intervention included local or wide local excision +/- nodal dissection (68%), radical resection +/- nodal dissection (22%), and amputation (4%). Five patients (6%) underwent biopsy only because of metastatic disease or unresectability at presentation. Fifty-one percent received adjuvant therapy consisting of external beam radiation therapy and/or combination chemotherapy.

RESULTS

With an average follow-up time of 39.5 months, 12% had persistent disease and 40% had recurrent disease. The median time to recurrence was 8 months with a mean of 10.6 months. Although the addition of adjuvant therapy did not affect survival, the recurrence rate was 32.5% for surgery +/- adjuvant radiation therapy +/- chemotherapy as compared with 52.7% for surgery-only patients. Although the 40.7% recurrence rate for patients receiving surgery and adjuvant radiation therapy was approximately the same as for patients receiving surgery and adjuvant chemotherapy (40%), the effect of systemic chemotherapy on recurrence is less clear as a result of the small number of patients who received such therapy. Although tumor size and site of presentation were not observed to be statistically significant in overall survival, significant differences were observed based on sex and tumor stage. For females, the median survival time was 96 months (mean, 94.5 months) compared with 63 months (mean, 76.8 months) for males. This difference was significant (P < 0.01). Patients presenting with low-stage (stage I) disease had a significant (P < 0.01) survival benefit when compared with high-stage individuals (stages II and III). The 5-year actuarial survival rates were 68% and 42%, respectively.

CONCLUSION

In this retrospective study, surgery remains the primary modality for Merkel cell carcinoma, and adjuvant radiation therapy +/- systemic chemotherapy reduces local recurrence. Female patients and those who present with early-stage disease appear to have a better prognosis.

[Merkel cell carcinoma. Clinical and histological differential diagnosis, diagnostic approach and therapy]

Merkel cell carcinomas are rare tumors of the skin with an aggressive behavior and frequent regional and distant metastases. Typically, the primary is a fast-growing, painless, reddish nodule with an iceberg-like effect, broadening in the depth. On the trunk and the buttocks, deep clinically rather inconspicuous nodules can occur. The clinical differential diagnosis of the Merkel cell carcinoma includes skin metastases, malignant lymphomas, malignant adnexal tumors and cysts when the tumor is located deep in the soft tissue (e.g. on the buttocks). Histological and immunohistochemical analysis is necessary for the diagnosis. The demonstration of cytokeratin 20 in the typical globular distribution pattern is of main importance in the diagnosis of Merkel cell carcinoma. Because they are very rare, Merkel cell carcinomas are infrequently diagnosed clinically, in spite of the rather characteristic picture. Diagnostic excision with a safety margin of 3 cm is recommended followed by an adjuvant radiotherapy. The radiation field should include the area of the draining vessels and the first regional lymph nodes. There are some reports concerning the advantage of sentinel lymph node biopsy. In distant metastases, the therapy is multimodal and palliative including surgery, radiation and chemotherapy. Because of the high incidence of regional and distant metastases, regular follow-up is important.

Oropharyngeal metastasis of a Merkel cell carcinoma of the skin

Merkel cell carcinoma (MCC) is an aggressive neuroendocrine tumor of the skin characterized by frequent local and regional recurrence, a high incidence of distant metastases and therefore a high mortality. Here, we report a case of an oropharyngeal metastasis of a Merkel cell carcinoma of the skin localized at the left base of the tongue causing dysphagia and the sensation of globus pharyngeus. The unusual metastatic site is presented, and diagnosis and treatment are discussed.

Fine-needle aspiration diagnosis of unusual cutaneous neoplasms of the scalp in HIV-infected patients: a report of two cases and review of the literature

We report on two unusual, non-AIDS-defining scalp neoplasms, Merkel-cell carcinoma (MCC) and malignant melanoma, in 2 men with acquired immunodeficiency syndrome (AIDS). In the first patient, metastatic MCC was initially diagnosed by fine-needle aspiration (FNA) of a posterior cervical lymph node, based on the cytomorphology and the characteristic immunohistochemical and ultrastructural features. No skin lesion was initially apparent, but a 0.3-mm scalp primary was found during the ensuing neck dissection. In the second patient, recurrent and metastatic malignant melanoma from a Breslow 1.3-mm scalp primary was diagnosed by FNA. Both patients developed generalized disease in a relatively short time, despite their small primaries. These cases illustrate the occurrence of Merkel-cell carcinoma and melanoma in AIDS patients, and stress the need to consider these unusual cutaneous neoplasms when evaluating lymph node FNA samples from HIV-positive patients, especially since both may present as metastases from clinically occult primaries.

Merkel cell carcinoma of the skin

BACKGROUND

Neuroendocrine/Merkel cell carcinoma (MCC) of the skin is an uncommon tumour. Currently, there are only limited data available on the natural history, prognostic factors, and patient management of MCC.

OBJECTIVES

To review our experience and build the largest database from the literature.

METHODS

Twenty-eight cases from the London Regional Cancer Center were combined with 633 cases obtained from the literature searched in English, French, German, and Chinese for the years 1966 to 1998. The database included age, sex, initial disease status at presentation to the clinic, site of primary, any coexisting disease, any previous irradiation, sizes of primary/nodal/distant metastases, management details, and final disease status. A new modified staging system was used: stage Ia (primary disease only, size > 2 cm), stage Ib (primary disease only, size > 2 cm); stage II (regional nodal disease), and stage III (beyond regional nodes and/or distant disease).

RESULTS

Age > 65 years, male sex, size of primary > 2 cm, truncal site, nodal/distant disease at presentation, and duration of disease before presentation (< or =3 months) were poor prognostic factors. Surgery was the initial treatment of choice and it significantly improved overall survival (p =.004).

CONCLUSIONS

We identified poor prognostic factors that may necessitate more aggressive treatment. The suggested staging system, incorporating primary tumour size, accurately predicted outcomes.

The Merkel cell carcinoma: survival and oncogene markers

BACKGROUND

Merkel cell carcinoma (MCC) is a rare and malignant tumour. Survival data and prognostic factors are scarce.

AIM

To investigate the usefulness of biological markers to predict the prognosis for these aggressive tumours.

METHODS

C-myc oncoprotein and proliferation was analysed in specimens from 13 patients with MCC, treated between 1983 and 1997. The average age at presentation was 68.3 years. Overall follow-up ranged from 14 to 158 months, with a mean of 68.2 months. Specimens were analysed by immunohistochemistry for proliferation (mib-1) and flow cytometry for oncogene activity (c-myc).

RESULTS

The median positivity was 52% for the c-myc oncogene and 50% for proliferation, but these did not correlate to survival as analysed by the Kaplan-Meier method. Other parameters such as median age at presentation, sex, site of tumour and adjuvant radiotherapy were also analysed, but none were found to be significant.

CONCLUSIONS

This study showed that neither c-myc oncogene activity or mitotic index in MCC can be related to patient survival.

Chemotherapy in neuroendocrine/Merkel cell carcinoma of the skin: case series and review of 204 cases

PURPOSE

To study the use of chemotherapy for Merkel cell carcinoma (MCC) of the skin.

PATIENTS AND METHODS

Twenty-five cases of MCC were treated at the London Regional Cancer Center between 1987 and 1997. Thirteen cases treated with chemotherapy were reviewed with 191 cases from the literature.

RESULTS

At presentation, 24 patients had localized skin lesions (stage I) and one had locoregional involvement (stage II). Among the nine cases with recurrent nodal disease, six had chemotherapy as a component of salvage treatment. They were all free of disease at a median of 19 months (range, 12 to 37 months). In contrast, two patients who had salvage radiotherapy alone died of disease. Overall survival (OS) and disease-free survival (DFS) were 59% and 43%, respectively, at two years. Median OS and DFS were 29 months (range, 1 to 133 months) and 9 months (range, 1 to 133 months), respectively. Nodal disease developed in 12 (50%) of 24 patients with stage I disease, and distant metastases developed in six (25%) of 24. Including those from the literature, there were 204 cases treated with chemotherapy. Cyclophosphamide/doxorubicin (or epirubicin)/vincristine combination +/- prednisone was the most commonly used chemotherapy regimen (47 cases), with an overall response rate of 75.7% (35.1% complete, 35. 1% partial, and 5.4% minor responses). Etoposide/cisplatin (or carboplatin) was the next most commonly used regimen (27 cases), with an overall response rate of 60% (36% complete and 24% partial responses). The difference in response rate was not statistically significant (P =.19). Among the 204 cases, there were seven (3.4%) toxic deaths.

CONCLUSION

Chemoradiation for locally recurrent or advanced disease may be an option for patients with a good performance status.

Lymphoscintigraphy, sentinel lymph node biopsy, and Mohs micrographic surgery in the treatment of Merkel cell carcinoma

BACKGROUND

Merkel cell carcinoma (MCC) is an aggressive cutaneous malignancy with a high incidence of occult nodal metastases. MCC is believed to be similar in natural history to thick or ulcerated melanomas in its propensity for locoregional recurrence and early lymph node metastasis. Studies have shown that nodal status is statistically correlated to survival in MCC. Radiolocalization and superselective lymph node biopsy is a recent technique that has been proven to be of great value in evaluating the status of occult lymph node disease in malignant melanoma and breast cancer patients.

OBJECTIVE

In previously untreated patients, an orderly progression of metastases is observed for both cutaneous carcinomas and malignant melanomas and is anticipated for MCC. METHODS/RESULTS. We present two patients with MCC of the head and neck who underwent simultaneous Mohs micrographic surgery and sentinel lymph node biopsy with intraoperative radiolocalization.

CONCLUSION

Sentinel lymph node biopsy and intraoperative lymphoscintigraphy may prove to be a useful technique in evaluating occult nodal involvement and in limiting the potentially unnecessary morbidity of more comprehensive lymph node dissections in MCC patients who do not yet have metastatic involvement.

Diagnostic relevance of chromosomal in-situ hybridization in Merkel cell carcinoma: targeted interphase cytogenetic tumour analyses

AIMS

To resolve the conflicting diagnoses of five pathologists (which included well-differentiated neuroendocrine carcinoma, malignant carcinoid, undifferentiated small-cell carcinoma, primitive neuroectodermal tumour, metastases of small-cell lung carcinoma (SCLC) and Merkel cell carcinoma (MCC)), and tumour-free lungs after necropsy, we investigated an alarmingly metastasizing MCC in a 32-year-old Caucasian man using chromosomal in-situ hybridization (CISH). Differences in incidence and course in males and females also prompted targeted analyses for chromosomes X and Y. The lesion was also analysed for p53 gene mutations.

METHODS AND RESULTS

Paraffin sections of the thorax, buccal lymph nodes and scalp tumours were stained with haematoxylin and eosin. Immunohistochemistry was performed with antibodies against pancytokeratin, keratin 20, neuron-specific enolase (NSE), chromogranin, neurofilaments and vimentin, among others. Sections (5-6 microm) of the tumours were analysed with alpha-satellite probes for chromosomes 1, 6, 7, 11, 12, 17, 18, X and Y using CrSH; and exons 5-9 of the p53 gene were examined by polymerase chain reaction and single strand conformation polymorphism (PCR-SSCP) methods. Although positive for pancytokeratin, keratin 20, chromogranin, NSE, synaptophysin and vimentin, the similarity in antigen profiles expressed by SCLC and MCC prevented a definitive tumour diagnosis. Chromosomal in-situ hybridization, however, revealed trisomies 1 and 11, two frequent aberrations in MCC, and trisomy 18. Moreover, 71% of the tumour cells had two to three copies of X, whereas 98% of the cell nuclei in the hair follicles and normal epidermis (purported Merkel cell origins) displayed one X chromosome. No mutations were detected in the five exons of the p53 gene examined.

CONCLUSIONS

Had CISH been performed earlier, treatment may have been tailored specifically to suit MCC, since MCC and SCLC have different therapeutic strategies. Finally, chromosome X may be of prognostic relevance in MCC, which apparently predominates in females and yet shows poorer prognosis in males, and hence be worthy of further investigation.

Mixed Merkel cell carcinoma and squamous cell carcinoma of the skin

Four mixed Merkel cell and squamous cell carcinomas of the skin are described. The patients ranged in age from 74 to 90 years and demonstrated or had a history of previous ultraviolet or infrared damage to the skin, manifested by basal cell carcinoma, squamous cell carcinoma, actinic keratoses, solar elastosis, and erythema ab igne. Light microscopic examination of all 4 cases revealed invasive neoplasms consisting of 2 distinct but admixed cell types. The predominant cell type was consistent with Merkel cell carcinoma and was characterized by scant cytoplasm, a small dark polygonal nucleus with granular chromatin, a high mitotic rate, and cytokeratin 20 positivity. In each case, the Merkel cell component merged with a cytokeratin 20 negative squamous component characterized by abundant eosinophilic cytoplasm, intercellular bridges, and keratinization with focal squamous pearl formation. Immunohistochemical staining patterns were consistent with the usual pattern for that cell type; transitional cells were not demonstrated. The intimate admixture of the 2 antigenically different neoplastic cell types, and common etiologic role of ultraviolet and possibly infrared damage, lend support to the theory that some Merkel cell carcinomas and squamous cell carcinomas may arise from a pluripotent epidermal stem cell.

Prognosticating tools in primary neuroendocrine (Merkel-cell) carcinomas of the skin: histopathological subdivision, DNA cytometry, cell proliferation analyses (Ki-67-immunoreactivity) and NCAM immunohistochemistry. A clinicopathological study in 25 patients

Histopathologically, 18 of our patients had classical Merkel-cell carcinomas (MCC); seven had neuroendocrine (NE) carcinomas with features different from MCC, here called "aberrant MCC". These patients showed a progressive neoplastic disease with a fatal outcome in four of them. The cytometric DNA distribution pattern of the tumor cell nuclei of all the aberrant MCCs was found to be of the aneuploid type. By contrast, the neoplastic disease of the majority of patients with classical MCC ran a milder course; a fatal outcome occurred in only one of them. Here, the DNA ploidy pattern was of the euploid (diploid or tetraploid) type in eight cases and of the aneuploid type in another eight. Our recently described "proliferation cell index" (PCI), based on nuclear immunoreactivity (IR) with the proliferation "marker" antigen Ki-67, was significantly lower in those five MCCs of the classical "DNA-diploid" type than in the seven "DNA-aneuploid" ones. These five patients presented a mild neoplastic disease; only one had a local recurrence and none had metastases. Otherwise, neither the PCI values nor the NCAM IR of the MCC cells were found to be of any prognostic significance.

Proliferation markers and prognosis in Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a frequently aggressive primary cutaneous neuroendocrine malignancy. We investigated 3 cell proliferation markers which may be useful in predicting the aggressiveness of MCC: 1) p53, a tumor suppressor protein, 2) Ki-67, a marker of cell cycling, and 3) proliferating cell nuclear antigen (PCNA). Twenty patients with MCC were studied. The 3 cell proliferation markers were studied by immunoperoxidase. Clinical and immunoperoxidase results were tabulated according to recurrence or death from disease. Of the 20 patients, 10 experienced recurrence, and 10 did not. Seven tumors were positive for p53. We found correlations between recurrence and death in MCC patients, between p53 positivity and recurrence/death, and between p53 positivity and head/neck primary sites. We found no correlation with recurrence by gender or primary site. PCNA was positive in only 1 patient, while Ki-67 was positive in all patients, making these 2 markers unsuitable for predicting recurrence. Further clinical studies will be helpful to confirm and refine the application of this test. Prognostic information from such studies may be useful in planning observation and treatment for patients in the future.

Merkel cell carcinoma of the skin

Primary neuroendocrine carcinoma of the skin or Merkel cell carcinoma is an aggressive primary neoplasm. It is commonly seen in the elderly, on the head, neck and extremities, where it can mimic a benign or less malignant skin tumour. Pathological examination shows a generally dense growth of small dark cells, with immunohistochemical evidence of neuroendocrine differentiation. The microscopic appearance is very similar to metastatic oat cell carcinoma from the lung and this must be excluded by clinical means and appropriate imaging studies. In this study we present 13 new cases of Merkel cell carcinoma (the largest published series in the UK) and summarize 214 cases from the literature in which the survival data are given. In our series, 5 of 13 patients died from spread of the Merkel cell carcinoma. From this and other studies, it appears that early diagnosis and wide local excision may be the only way to prolong survival. No other adjuvant therapy has proved effective.

Gingival metastasis of merkel cell carcinoma: a case report

An 82-year-old Caucasian man developed an ulcerated mass on the anterior mandibular gingiva. Five years previously he had been treated for a Merkel cell carcinoma (MCC) on his right cheek. Histopathologic examination showed small tumor cells with scanty cytoplasm, suggestive of malignancy. Immunohistochemical studies were performed with the use of nine antibodies. S-100 protein and leukocyte common antigen were helpful in ruling out melanoma and lymphoma. Pronounced reaction was shown for cytokeratin 20, a new histodiagnostic marker whose expression is almost entirely confined to Merkel cells, the gastric epithelium, and urothelium. The tentative diagnosis of metastasis of MCC was confirmed. Immunohistochemical studies are useful diagnostic aids in the establishment of the diagnosis of Merkel cell carcinoma.