Merkel cell carcinoma of the eyelid: histological and immunohistochemical features with special respect to differential diagnosis

Merkel cell carcinoma and the eye

Merkel cell carcinoma (MCC) is a rare cutaneous neuroendocrine tumor with a poor five-year survival rate. Yearly cases have risen nearly 350% since the early 1980s, and these are predicted to increase as the overall US population ages. MCC of the eyelid is uncommon and can be misdiagnosed as other benign inflammatory and neoplastic eyelid disorders. Although MCC of the head and neck is often more aggressive than it is at other sites, eyelid MCC shows a lower disease-specific mortality rate. A biopsy is essential for accurate diagnosis, including an immunohistochemical panel of CK20 and TTF-1, although other markers may be necessary. Staging can be assessed clinically through physical examination findings and imaging and/or pathologically with sentinel lymph node biopsy or fine-needle aspiration. Pathologic staging more accurately predicts the prognosis. Eyelid MCC treatments include Mohs micrographic surgery to allow for complete clearance and adequate reconstruction of lost tissue, followed by adjuvant radiotherapy. In advanced disease, immunotherapies are preferred over traditional chemotherapy and are a subject of ongoing research.

ATOH1, TFAP2B, and CEACAM6 as Immunohistochemical Markers to Distinguish Merkel Cell Carcinoma and Small Cell Lung Cancer

Merkel cell carcinoma (MCC) and small cell lung cancer (SCLC) can be histologically similar. Immunohistochemistry (IHC) for cytokeratin 20 (CK20) and thyroid transcription factor 1 (TTF-1) are commonly used to differentiate MCC from SCLC; however, these markers have limited sensitivity and specificity. To identify new diagnostic markers, we performed differential gene expression analysis on transcriptome data from MCC and SCLC tumors. Candidate markers included atonal BHLH transcription factor 1 (ATOH1) and transcription factor AP-2β (TFAP2B) for MCC, as well as carcinoembryonic antigen cell adhesion molecule 6 (CEACAM6) for SCLC. Immunostaining for CK20, TTF-1, and new candidate markers was performed on 43 MCC and 59 SCLC samples. All three MCC markers were sensitive and specific, with CK20 and ATOH1 staining 43/43 (100%) MCC and 0/59 (0%) SCLC cases and TFAP2B staining 40/43 (93%) MCC and 0/59 (0%) SCLC cases. TTF-1 stained 47/59 (80%) SCLC and 1/43 (2%) MCC cases. CEACAM6 stained 49/59 (83%) SCLC and 0/43 (0%) MCC cases. Combining CEACAM6 and TTF-1 increased SCLC detection sensitivity to 93% and specificity to 98%. These data suggest that ATOH1, TFAP2B, and CEACAM6 should be explored as markers to differentiate MCC and SCLC.

Prevalence of Merkel Cell Polyomavirus in Primary Eyelid Merkel Cell Carcinomas and Association With Clinicopathological Features

PURPOSE

Merkel cell polyomavirus (MCPyV) infection is a known to be a critical risk factor for the development of Merkel cell carcinoma (MCC). Various reports on cutaneous MCC have shown that the differences in clinicohistopathological characteristics depend on the presence of MCPyV, but the situation in eyelid MCC is unknown. This study aimed to assess the prevalence of MCPyV in patients with eyelid MCC and examine the clinicohistopathological characteristics of MCPyV-associated eyelid MCC.

DESIGN

Retrospective observational case series with laboratory investigations.

METHODS

Ten patients treated for eyelid MCC were included. Histopathological characteristics were examined by immunohistochemical staining using 12 antibodies. MCPyV infection was evaluated by PCR using primer sets targeting large T antigens of the MCPyV genome and by immunohistochemical staining using CM2B4 and Ab3 monoclonal antibodies. The MCPyV viral load was also quantified by PCR using 3 primer sets.

RESULTS

All patients (4 males and 6 females) were Japanese with mean age of 79 (range: 63 to 87) years. One patient died due to distant metastasis 8 months after surgery for MCC. Immunohistochemical studies showed typical MCC findings in all cases, including CK20 and neuroendocrine marker positivity. PCR and immunohistochemistry with CM2B4 and Ab3 detected MCPyV antigen in all tumors. Quantitative PCR using sT, LT4, and TAg primers yielded 0.94, 1.72, and 1.05 copies per cell, respectively.

CONCLUSION

Clinical and histopathological characteristics of 10 patients with eyelid MCC were elucidated. MCPyV infection was detected in all eyelids. These results provide insight for understanding the tumorigenesis of eyelid MCC.

Basaloid Follicular Hamartoma of the Eyelid: A Case Report and Literature Review about an Unusual Lesion in the Ocular Region

Basaloid follicular hamartoma (BFH) is a normally benign, uncommon, malformative lesion involving the hair follicles, which usually poses challenges in the differential diagnosis with other benign and malignant tumours, especially basal cell carcinoma, due to significant clinical and morphological overlap. Here, we report the case of a 53-year-old male who presented with a mass in the upper left eyelid evolving for one year. The patient had a previous history of total colectomy and an abdominal desmoid tumour within the context of Familial Adenomatous Polyposis (FAP), with a documented germline mutation in the Adenomatous Polyposis Coli (APC) gene. The eyelid lesion was biopsied and the histological analysis of the three small tissue fragments received revealed fragments with cutaneous–conjunctival lining displaying a subepithelial proliferation of basaloid nests with peripheral palisading, compatible with primitive hair follicles. There were images of anastomosis between different basaloid nests, which had their connection to the epithelial lining preserved. The stroma had high cellularity and sometimes primitive mesenchymal papillae were evident. Pleomorphism was absent, mitotic figures were barely identified, and no necrosis was seen. The basaloid nests did not have epithelial–stromal retraction nor mucin deposits. A diagnosis of BFH was proposed, which was later confirmed after surgical excision of the whole eyelid lesion. No evidence of carcinoma was present. This case illustrates the main features of the rare benign eyelid BFH. The standard medical or surgical approach of these lesions remains to be firmly established. Nearly nine months after surgical excision our patient remains well without signs of disease recurrence.

Danger is only skin deep: aggressive epidermal carcinomas. An overview of the diagnosis, demographics, molecular-genetics, staging, prognostic biomarkers, and therapeutic advances in Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a high grade primary cutaneous neuroendocrine carcinoma and is among the most aggressive cutaneous malignancies. The rising incidence of MCC, together with its often rapidly aggressive course, underscore a critical need to recognize the histopathologic and the immunohistochemical features that inform its accurate diagnosis. In the current review, we summarize the current state of knowledge regarding the accurate diagnosis of MCC and the exclusion of other entities in the differential diagnosis. We provide a comprehensive review of genomic studies that identified the molecular-genetic drivers of MCC as well as a summary of studies identifying prognostic biomarkers that can facilitate risk stratification. Importantly, Merkel cell polyomavirus (MCPyV) appears to be causative in most cases of MCC and represents both a diagnostic and prognostic marker. Finally, as staging of MCC has undergone critical refinements with the introduction of the 8th Edition of the American Joint Committee on Cancer staging system, we provide an update on MCC staging. In particular, the prognostic significance of the sentinel lymph node (SLN) in MCC necessitates a systematic approach to its evaluation and diagnosis to ensure accurate and consistent risk stratification for patients, and we therefore provide a comprehensive overview of SLN evaluation in MCC. Finally, the intimate relationship between MCC and the integrity of the host immune system has led to paradigm-shifting therapeutic advances with the successful application of immune checkpoint blockade to treat patients with advanced disease, and we therefore summarize those studies and the correlative studies in which predictive biomarkers have been identified.

Merkel cell carcinoma of the eyelid: A review

Merkel cell carcinoma (MCC) is a rare, aggressive tumor of both epithelial and neuroendocrine origin, which carries a mortality rate of up to 40%. MCC tumors typically present as painless, expanding nodules on the sun-exposed skin areas of older, white patients. Eyelid and periocular tumors comprise approximately 2.5% of all cases of MCC and may be mistaken for chalazia or basal cell carcinomas. Immunosuppression is a significant risk factor, particularly in solid-organ-transplant recipients, patients with chronic lymphocytic leukemia, and patients with HIV. Sentinel lymph node biopsy is often used for accurate staging of head and neck MCC. Treatment includes wide local excision, commonly with the addition of radiotherapy for improved locoregional disease control. Historically, adjuvant chemotherapy had been reserved for metastatic disease, but immunotherapy and targeted chemotherapies are currently being investigated for use in primary disease. The clinical characteristics of all available published cases of eyelid MCC are summarized in this article.

Merkel cell carcinoma of the thigh: case report and review of the literature

BACKGROUND

Merkel cell carcinoma (MCC) is a kind of cutaneous neuroendocrine cancer with a poor prognosis. It is characterized by a high rate of recurrence and metastases, including distant metastases and regional nodal metastases. Clinically, MCC often manifests as obvious single painless hard nodules visible in sun irradiation of diameter <2 cm and not uncommonly >2 cm, with rapid growth and metastases, especially lymph node metastases. Due to the aspecific nature of MCC, it is often confused with other skin cancers. Exploring different treatments of MCC is necessary.

CASE PRESENTATION

The current study describes the case of an 86-year-old retired man, who presented with a 2.5×2.0×1.2 cm red nodule on the right thigh, which was initially diagnosed as subcutaneous small cell cancer. Upon histological and immunohistochemical analysis, the tumor was consistent with a diagnosis of MCC.

RESULTS

Antiangiogenic therapy combining endostar and apatinib was administered and a partial response achieved after 2.0 months of treatment, and 6.5 months of progression-free survival was achieved. Overall survival was 13.0 months.

CONCLUSION

We believe that antiangiogenic therapy is an extremely effective treatment for MCC, especially for patients who cannot tolerate chemotherapy and radiotherapy.

A case series of Merkel cell carcinoma of the eyelid: a rare entity often misdiagnosed

Merkel cell carcinoma (MCC) is one of the rarest eyelid tumors, with high mortality rate due to lymphatic and metastatic spread. We hereby report six cases of patients with histological diagnosis of MCC referred to our Orbit Unit between 2012 and 2018, focusing on diagnosis, treatment, and subsequent follow up. All patients underwent surgical excision and systemic work-up. Both MCC TNM and eyelid MCC TNM were used to stage lesions. MCC of the eyelid is usually misdiagnosed as benign or other malignant lesions. A prompt examination and a wide local excision are mandatory. A close follow-up of these patients is advised due to high recurrence rate and lymphatic spread.

Lymph Node Metastases of Merkel Cell Carcinoma from Unknown Primary Site: Report of Three Cases

Merkel cell carcinoma (MCC) is an uncommon aggressive neuroendocrine skin carcinoma. It usually affects sun-exposed skin of white elderly people. MCC is characterized by a high incidence of early locoregional relapse and distant metastases. Because of its rarity and the resulting lack of prospective randomized trials, data regarding the optimal treatment of MCC are limited. Despite aggressive multimodality treatment, the prognosis of patients bearing MCC is often poor. We report three cases of lymph node metastases of MCC with unknown primary sites. Two patients died 17 and 28 months after diagnosis due to brain and pancreatic metastases, respectively, without evidence of cutaneous disease. The third patient is alive and free of tumor at 16 months from the diagnosis. After an accurate diagnosis of lymph node metastases from MCC, the absence of a primary tumor at complete initial evaluation and during adequate follow-up can confirm this particular clinical scenario. The prognosis seems to be analogous to that of cases with similar disease stage (lymph node involvement) but a known primary site.

Spontaneous regression of Merkel cell carcinoma: A case report and review of the literature

INTRODUCTION

Merkel cell carcinoma (MCC) is a rare and highly aggressive primary cutaneous neuroendocrine carcinoma, most often occurring in the elderly. Recurrence is frequent and in 40% of cases regional and distant metastases develop. Despite this, there have been reports of spontaneous regression. We report the first case of MCC with primary complete spontaneous regression of the nose in an 86-year-old woman following an incisional biopsy.

PRESENTATION OF CASE

An 86-year-old woman presented with a violaceous lump on the left side of the nose measuring 25 × 25 mm. Incisional biopsy of the lesion showed MCC and immunohistochemistry confirmed diagnosis. Following an 8-week period the lesion completely disappeared and histology did not show any residual MCC but immunohistochemistry demonstrated a mixture of T and B cells.

DISCUSSION

Complete spontaneous regression (CSR) is rare. The literature documents 22 similar cases of CSR of MCC. From this case report and previous literature the most likely reason for regression is a T-cell mediated immune response.

CONCLUSION

To the best of our knowledge, this is the first described case of MCC with primary CSR of the nose. Exact mechanism of regression remains unclear. Further research is needed in identifying pathway of immune response and possible immunotherapy as a cure.

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.

A better prognosis for Merkel cell carcinoma of unknown primary origin

BACKGROUND

There is limited evidence that Merkel cell carcinoma (MCC) arising from a nodal basin without evidence of a primary cutaneous (PC) site has better prognosis. We present our experience at 2 tertiary care referral centers with stage III MCC with and without a PC site.

METHODS

Fifty stage III MCC patients were identified between 1996 and 2011. Clinical data were analyzed, with primary endpoints being disease-free survival and overall survival.

RESULTS

Of stage III patients, 34 patients presented with a PC site and 16 patients with an unknown primary (UP) site. Treatment strategies varied; of patients with UP vs. PC sites, 25% vs. 44% underwent combined regional lymphadenectomy and radiation, with an additional 25% vs. 15% receiving chemotherapy. The median disease-free survival for a UP site was not reached vs. 15 months for a PC site (hazards ratio = .48, P = .18). The median overall survival for a UP site was not reached vs 21 months for a PC site (hazards ratio = .34, P = .03). Multivariate analysis showed that UP status was a significant factor in overall survival (P = .002).

CONCLUSIONS

Stage III MCC with a UP site portends a better prognosis than MCC with a PC site.

Unusual Merkel cell carcinoma of the eyelid

Merkel cell carcinoma of the eyelid is a rare tumor with less than 100 reported cases worldwide. We describe an unusual presentation of Merkel cell carcinoma of the eyelid in a 60 year old Asian male. He presented with multiple left lower lid conjunctival nodules, intense conjunctival erythema, as well as ipsilateral cervical lymphadenopathy. An incisional biopsy diagnosed him with Merkel cell carcinoma with a PET scan showing distant metastatic disease. He was then treated with chemotherapy. The combination of a presentation of conjunctival nodules and erythema, location in the lower eyelid and the conjunctiva, the presence of metastatic disease on diagnosis as well as an unusual immunohistochemical profile make this an unusual case.

Merkel cell carcinoma. A review

BACKGROUND

Merkel cell carcinoma (MCC) is a rare potentially fatal skin tumour affecting older mainly white people and younger immunosuppressed individuals. While uncommon, the incidence is increasing relative to melanoma and with twice the lethality. The benign appearance of the tumour usually on exposed skin parts, contrasting with its extensive microscopic invasion, can delay timely diagnosis. Recurrent MCC is currently attributed to the recently discovered Merkel cell polyomavirus This brief review of MCC covers the history, epidemiology,etiology,clinical and histological features, treatment and prognosis.

METHODS

Literature search using PubMed and search words Merkel cell carcinoma (MCC), etiology, treatment for the years 1972 to 2010.

RESULTS AND CONCLUSION

Merkel cell carcinoma is a rare malignancy with uncertain prognosis. Due to the uncommon occurrence and dearth of randomized studies, there is no agreement on optimal treatment. The tumor has only recently been included in the international classification of tumors (NCCN). The treatment approaches found to be best are radical surgery of primary tumor, drainage of lymph node extension and possibly adjuvant loco-regional radiotherapy. The basis of successful treatment however, remains prevention regular dermatological examination in immunosuppressed patients and early initiation of combination therapy, based on radical surgery supplemented by radiotherapy and palliative chemotherapy in the last resort.

Periocular cutaneous malignancies: a review of the literature

BACKGROUND

The periocular skin is susceptible to numerous benign and malignant neoplasms. Periocular malignancies may present differently, behave more aggressively, and pose greater challenges for treatment and repair than malignancies at other cutaneous sites. Between 5% and 10% of cutaneous malignancies occur periorbitally, with basal cell carcinoma reported as the most common malignant periocular tumor, followed by squamous cell carcinoma, sebaceous gland carcinoma, cutaneous melanoma, Merkel cell carcinoma, and other rare tumors.

OBJECTIVE

To review the current literature on cutaneous malignancies of the periocular region pertaining to etiology, incidence, clinical presentation, differential diagnosis, complications, and treatment options.

MATERIALS AND METHODS

An extensive literature review was conducted using PubMed, searching for articles on periocular and periorbital cutaneous malignancies.

CONCLUSIONS

Timely diagnosis and management of periocular malignancies is essential because of their proximity to and potential to invade vital structures such as the orbit, sinuses, and brain. Surgical excision remains the standard of care for the majority of periorbital malignancies, but given the sensitive anatomic location, tissue-sparing techniques with margin control such as Mohs micrographic surgery are the preferred method for most nonmelanoma skin cancers. Depending on tumor type, other treatment modalities may include radiation, chemotherapy, cryosurgery, topical medications, and photodynamic therapy.

Clinicopathologic and immunohistochemical features of pigmented Basal cell carcinomas of the eyelids

PURPOSE

To describe the clinical and microscopic features of pigmented basal cell carcinomas (pBCC) of the eyelid.

DESIGN

Retrospective observational case series collected at one institution.

METHODS

An analysis of clinical records, photographs, and histopathologic characteristics of 257 BCCs with a review of the literature. The frequencies of clinically pigmented, and of microscopically pigmented but clinically nonpigmented, BCCs were determined. Cytochemical stains (Fontana-Masson, Prussian blue) and immunohistochemical probes (S-100, microphthalmia-associated transcription factor [MiTF], HMB-45, MART-1, CK20, synaptophysin, chromogranin, CD1a, Ki-67) were then employed and the findings correlated with the degree of clinical pigmentation.

RESULTS

Histopathologically, 13 of 257 cases (5.06%) were found to have pigment; of these 13, 6 (all white patients) had clinically apparent pigmentation (2.33%), either focal or diffuse. Eight of 13 lesions developed on the lower eyelids. All stained positively for melanin but negatively for iron. MiTF highlighted numerous melanocytic nuclei in the tumor lobules, while MART-1 and HMB-45 revealed the dendritic shapes of the entrapped melanocytes. There was a subtotal blockage of melanin transfer to the surrounding basaloid cells. Intralobular S-100-positive cells included CD1a-positive Langerhans cells, while CK20 did not identify any Merkel cells.

CONCLUSIONS

Only 1 of 6 lesions was uniformly clinically pigmented, whereas the other 5 were only focally brown-black. The clinical pigmentation was imparted by varying densities and distributions of melanocytes with arborizing dendrites, which were present in all BCCs. Melanophages within the stroma and basaloid cell melanization also contributed to pigmentation. No behavioral or biologic differences in pBCC were documented compared with clinically nonpigmented lesions.

Giant Merkel cell carcinoma of the eyelid: a case report and review of the literature

Merkel cell carcinoma (MCC) is a rare cutaneous tumor and cases located in the eyelid have been described, but still its rarity may lead to difficulty in diagnosis and delay in treatment. A 51-year-old female patient that presented with large lesions in the eyelid underwent surgery after the diagnosis of acute chalazion. Following respiratory distress secondary to pulmonary metastasis, the patient's condition deteriorated and was not fit for complete excision treatment. Histopathological investigation of the biopsies, taken from the tumor, revealed that it was undifferentiated small cell carcinoma. Our aim with this paper is to point out that more cases should be reported for more effective diagnosis, histopathological study, clinical investigation, treatment and prognosis of this specific neoplasm.

Merkel cell carcinoma in a cat

A 17-year-old spayed female Japanese domestic cat presented with a solitary cutaneous mass in the right thoracic area. Histopathologically, the mass consisted mainly of round tumor cells that had infiltrated throughout the dermis and deep subcutaneous tissue. The proliferating pattern of tumor cells was solid but also trabecular or cord-like in some areas, and lined with small cells resembling mature lymphocytes or basal cells. The tumor cells were positive for cytokeratin 20 and synaptophysin. The positive reaction for cytokeratin 20 showed localized to diffuse pattern. This is the first report describing now cytokeratin 20 was clearly beneficial for the differential diagnosis of feline Merkel cell carcinoma.

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.

Immunohistochemical distinction between merkel cell carcinoma and small cell carcinoma of the lung

We assessed the usefulness of several immunohistochemical stains in distinguishing these two neoplasms, including cytokeratin 7, cytokeratin 20 (CK20), neuron-specific enolase, chromogranin, synaptophysin, neurofilaments (NF), thyroid-transcription factor-1 (TTF-1), CD56 antigen, S-100 protein, vimentin, c-erbB-2 oncoprotein, and CD117 antigen. All 13 cases of Merkel cell carcinoma evaluated were positive for CK20, and negative for TTF-1. Twelve of 13 Merkel cell carcinoma cases were positive for NF. Eleven of 13 cases of small cell lung carcinoma were positive for TTF-1. All small cell lung carcinoma cases were negative for NF, and all but one were negative for CK20. In terms of the remaining antigens, there were no differences of significance between the two neoplasms. These findings suggest that a set of three immunohistochemical stains, including CK20, NF, and TTF-1, is useful in affording a distinction between Merkel cell carcinoma and small cell lung carcinoma.

Immunohistochemical staining for adipophilin, perilipin and TIP47

BACKGROUND

The presence of lipid in the cell cytoplasm is useful for supporting the diagnosis of sebaceous gland carcinoma (SGC). Currently this requires histochemical stains that are carried out on frozen sections of unprocessed tissue. Recently, several anti-adipocytic antibodies that recognise proteins associated with lipid vesicles have been described. These antibodies can be applied to paraffin-wax sections.

AIM

To assess the ability of anti-adipocytic antibodies to identify intracytoplasmic lipid in SGC.

METHODS

Immunohistochemistry with a monoclonal antibody to adipophilin and polyclonal antibodies to perilipin and TIP47/PP17 was carried out on archival, formalin-fixed, paraffin-wax-embedded sections of 26 samples of SGC. The immunostaining was compared with 22 other eyelid tumours (11 basal cell carcinomas (BCC), 10 squamous cell carcinomas (SCC) and 1 Merkel cell tumour).

RESULTS

Immunohistochemical staining was positive in 23, 10 and 2 cases of 26 SGC with adipophilin, perilipin and TIP47, respectively. The positive staining identified cytoplasmic lipid vesicles. Anti-adipophilin was positive in five other eyelid tumours (4 BCC and 1 SCC) staining small cytoplasmic granules that can be easily distinguished from the staining in SGC.

CONCLUSIONS

Immunohistochemical staining for adipophilin and perilipin is a useful ancillary technique for the demonstration of lipid in SGC that may be applied to paraffin-wax sections.

Merkel cell carcinoma

Background

Merkel cell carcinoma (MCC) is an unusual primary neuroendocrine carcinoma of the skin. MCC is a fatal disease, and patients have a poor chance of survival. Moreover, MCC lacks distinguishing clinical features, and thus by the time the diagnosis is made, the tumour usually have metastasized. MCC mainly affects sun-exposed areas of elderly persons. Half of the tumours are located in the head and neck region.

Methods

MCC was first described in 1972. Since then, most of the cases reported, have been in small series of patients. Most of the reports concern single cases or epidemiological studies. The present study reviews the world literature on MCC. The purpose of this article is to shed light on this unknown neuroendocrine carcinoma and provide the latest information on prognostic markers and treatment options.

Results

The epidemiological studies have revealed that large tumour size, male sex, truncal site, nodal/distant disease at presentation, and duration of disease before presentation, are poor prognostic factors. The recommended initial treatment is extensive local excision. Adjuvant radiation therapy has recently been shown to improve survival. Thus far, no chemotherapy protocol have achieved the same objective.

Conclusion

Although rare, the fatality of this malignancy makes is important to understand the etiology and pathophysiology. During the last few years, the research on MCC has produced prognostic markers, which can be translated into clinical patient care.

S-100 protein immunoreactivity in the upper eyelid of the sheep Ovis aries

The aim of this work was to analyse the distribution pattern of S-100-immunoreactive elements in the upper eyelid of the sheep. This pattern may be of importance regarding the diagnosis and prognosis of eyelid tumours that are linked to deregulation of S-100 gene expression. Thirty upper eyelids taken from 15 adult male Ovis aries were studied by means of the peroxidase-antiperoxidase method for light microscopy. S-100-immunopositive cells were found in the eyelid edge. S-100-immunopositive steams and thinner fibres were found throughout the eyelid. These nerve processes typically were denser around glands, hair follicles and blood vessels. S-100-immunopositive elements may play a role as neuromodulator and also in the development of the vegetative innervation of the epithelium and its derivatives.

[Merkel cell carcinoma]

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.

Gene-expression profiling reveals distinct expression patterns for Classic versus Variant Merkel cell phenotypes and new classifier genes to distinguish Merkel cell from small-cell lung carcinoma

Merkel cell carcinoma (MCC) is a rare aggressive skin tumor which shares histopathological and genetic features with small-cell lung carcinoma (SCLC), both are of neuroendocrine origin. Comparable to SCLC, MCC cell lines are classified into two different biochemical subgroups designated as 'Classic' and 'Variant'. With the aim to identify typical gene-expression signatures associated with these phenotypically different MCC cell lines subgroups and to search for differentially expressed genes between MCC and SCLC, we used cDNA arrays to profile 10 MCC cell lines and four SCLC cell lines. Using significance analysis of microarrays, we defined a set of 76 differentially expressed genes that allowed unequivocal identification of Classic and Variant MCC subgroups. We assume that the differential expression levels of some of these genes reflect, analogous to SCLC, the different biological and clinical properties of Classic and Variant MCC phenotypes. Therefore, they may serve as useful prognostic markers and potential targets for the development of new therapeutic interventions specific for each subgroup. Moreover, our analysis identified 17 powerful classifier genes capable of discriminating MCC from SCLC. Real-time quantitative RT-PCR analysis of these genes on 26 additional MCC and SCLC samples confirmed their diagnostic classification potential, opening opportunities for new investigations into these aggressive cancers.

Eyelid Merkel Cell Carcinoma: Report of Three Cases

PURPOSE

To present three cases of Merkel cell carcinoma, a primary cutaneous neuroendocrine tumor that arises from Merkel cells, and to describe their clinical features, diagnosis, and management.

METHODS

Case series.

RESULTS

In only one case, the disease was clinically recognized. In the others, the diagnosis was confirmed by histology, and chalazion was initially suspected in one of them. Surgery was performed in all patients, and there was no evidence of metastatic disease.

CONCLUSIONS

The rarity of eyelid Merkel cell carcinoma and the fact that it can simulate benign entities frequently lead to difficulties in diagnosis and a delay in the establishment of suitable therapy.

[Merkel cell carcinoma: descriptive study of 24 cases (1993-2001)]

INTRODUCTION

Merkel cell carcinoma (MCC) is a rare skin tumor with a highly malignant nature whose appropriate treatment is still debated. Wide surgery is the treatment of choice, but the question concerning protocols for adjuvant radiotherapy or chemotherapy remains open.

PATIENTS AND METHODS

A retrospective analysis of 24 cases of MCC collected over a period of 9 years was performed, focusing on clinical and histologic features, and response to treatment.

RESULTS

There were 17 women and 7 men with a mean age of 74.3 years. The median follow up was 34 months. The annual incidence per 100,000 habitants was 0.378. The head and neck localization was predominant (54%). Fifteen (68%) of patients presented with local disease (stage I), and 32% of patients presented with regional node (stage II) or distant metastases (stage III). Patients with stage I had a 5-years overall survival rate of 73,85%. Among them, five patients (33%) developed a local or nodal recurrence, although two patients were initially treated with surgery and local post-operative radiotherapy. Patients with stage II and III demonstrated a 5-year overall survival rate of 51,43%.

DISCUSSION

Our series illustrates the clinical characteristics of this tumor of the elderly, which is mainly located on head and neck and associated with a poor prognosis. Treatments are discussed.

Merkel cell carcinoma of the head and neck: a retrospective case series

BACKGROUND

Eighty-five percent of all Merkel cell carcinomas appear on sun-exposed areas, with 50% to 55% occurring on the head and neck.

METHODS

A chart review was performed on 22 patients treated for Merkel cell carcinoma of the head and neck between 1981 and 1998.

RESULTS

Fifteen patients were men (68%). The average age at operation was 69.9 years (range, 24-84 years). The average duration of follow-up was 3.6 years (range, 3 days-8.6 years). Overall survival at 1, 2, and 3 years postoperatively was 78%, 68%, and 68%, respectively. The only independent predictor of survival was the type of surgical therapy. All patients who underwent wide local excision (WLE) of the primary tumor with dissection of the lymphatic drainage basin were alive at 2 years as opposed to 68% who had WLE alone and 33% who had Mohs surgery.

CONCLUSIONS

WLE and dissection of the lymphatic drainage basin provided the best overall survival.

Clinicopathologic and electron microscopic study of cutaneous neuroendocrine (Merkel cell) carcinoma in a cat with comparisons to human and canine tumors

Malignant neuroendocrine carcinoma of the skin (Merkel cell tumor) was diagnosed in an 18-year-old spayed female Maine Coon Cat. The diagnosis was made on the basis of morphologic and electron microscopic findings. The cat was euthanatized 321 days after surgical excision of the tumor. The tumor's malignancy contrasted with the benign nature of Merkel cell tumors reported in dogs and was consistent with the malignancy of Merkel cell tumors reported in humans.

Merkel cell carcinoma arising in the head and neck: optimizing therapy

Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine dermal neoplasm. Because of the limited number of cases described in the literature (approximately 600 to date), statistically significant data regarding treatment are difficult to obtain. The majority of MCC cases affect the head and neck and are thought to be caused by the actinic damage associated with sun exposure. This study evaluates cases of head and neck MCC at Naval Medical Center San Diego (NMCSD) and compares the treatment regimens and outcomes from multiple institutions. This study is a retrospective outcomes analysis of all cases of head and neck MCC seen at NMCSD, between January 1, 1988 and June 30, 1998. The records of the NMCSD Tumor Registry were searched for patients with that diagnosis, and supplemental information was retrieved from the Radiation Oncology and Head & Neck Surgery Clinic charts. Eight of nine patients in this study were treated with either wide-local excision or Mohs microsurgery. The surgical margins were free of disease in all eight patients. One patient presented with distant metastatic disease, and two others were subsequently found to have nodal involvement. Subsequent therapy varied among the patients. Survey of the available literature revealed inconsistency in terms of which treatment regimens are optimal. Tumor resections are recommended by most groups to include a 2-cm to 3-cm tumor-free margin around the primary lesion when possible, but this is often difficult to achieve in the head and neck. Data, which do not reach statistical significance, suggest improved outcomes with tumor-free margins. Treatment of the regional draining lymph nodes is also recommended in most series. Prophylactic lymph node dissection or radiation therapy to the nodal chain may decrease local recurrence but does not consistently affect overall survival. Adjuvant chemotherapy is advocated by most groups in the treatment of metastatic disease because MCC is pathologically similar to small-cell lung carcinoma. However, no chemotherapy protocol has been shown to improve survival. Head and neck MCC is a rare and aggressive dermal tumor of neuroendocrine origin that requires multimodality therapy, including surgery, radiation therapy, and possibly adjuvant chemotherapy. Multiinstitutional studies are crucial to obtain sufficiently large populations to investigate and optimize therapy in this disease.

Merkel cell carcinoma: clinicopathologic correlation, management, and follow-up in five patients

PURPOSE

To review the clinicopathologic features, management and follow-up in five patients with periocular Merkel cell carcinoma (MCC).

METHODS

In this case series study we reviewed the clinical records and histopathologic findings of five consecutive patients with MCC, treated and followed between May 1991 and November 1998.

RESULTS

Four patients were female and one was male. Their mean age at the time of surgery was 80 years (range: 69-86 years). Patients presented with a painless, nonulcerated, rapidly growing, solitary reddish or violaceous nodule, ranging in size from 11 to 21 mm, located in the upper eyelid in 4 patients and in the left eyebrow in one patient. Management included excision with frozen section control in three patients, and excision with wide surgical margins in two patients. Histopathologically, all tumors exhibited round cells of intermediate size and scanty cytoplasm, and large, round to oval vesicular nuclei with finely dispersed chromatin and one to three inconspicuous nucleoli. Mitotic figures were numerous. No patient had regional or extraregional metastases at diagnosis. Local recurrence or distant metastases were not detectable during a mean follow-up period of 45 months (range: 32-61 months). This outcome contrasts with the high incidence of local recurrence and early nodal metastasis reported in previous publications.

CONCLUSIONS

Early diagnosis and aggressive, histologically controlled surgical treatment of this rare, highly malignant tumor may provide a longer disease-free period. Further investigation is necessary to determine the prognostic factors for recurrence and survival.

Merkel cell carcinoma of the eyebrow extending into the orbit

BACKGROUND

Merkel cell carcinoma is a rare and aggressive cutaneous neoplasm with high local recurrence and metastatic rates.

PURPOSE

To highlight an unusual presentation of a Merkel cell carcinoma.

CASE REPORT

We report a large Merkel cell tumor in an 85-year-old woman. It extended from the eyebrow into the upper nasal orbit posterior to the equator of the eye globe. Local resection resulted in microscopically complete removal of the tumor. During follow-up (20 months) no local recurrence was noticed but there was a metastasis in a lymphatic nodule.

CONCLUSIONS

Merkel cell carcinoma often presents in the eyelids and periorbital region. However, extension from the eyebrow deep into the orbit is unusual.

Magnetic resonance imaging appearance of metastatic Merkel cell carcinoma to the sacrum and epidural space

Merkel cell carcinoma (MCC) is a rare malignant tumor of the skin and often is diagnosed histologically as lymphoma, melanoma and even metastatic small cell carcinoma of the lung (SCCL). Classified as a neuroendocrine tumor, clinically it originates in the head and neck region and may present with metastatic disease at the time of presentation [1]. Osseous involvement in the past has been described to involve regional facial bones only. We present the first reported MRI findings of distant osseous metastasis from a Merkel cell carcinoma to the lumbosacral spine with associated soft tissue and epidural involvement. Appropriate treatment and patient survival depend on prompt diagnostic imaging for establishment of metastatic disease. Previous reports have advocated CT for diagnosis and staging of distant metastases [2,3]. When spinal involvement is suspected, MRI may be a more suitable modality for assessment of the epidural space and appropriate staging and follow-up in such cases.

Merkel cell carcinoma of the eyelid: a case report

A 22-year-old woman who presented with a tumour of the upper eyelid with clinical, histological, immunohistochemical and ultrastructural features of a Merkel cell carcinoma is reported. This is a unique case of Merkel cell carcinoma in such a young patient. This neuroendocrine tumour is typically found in the elderly. It can grow rapidly, has the potential for local recurrence and early metastatic spread. The authors recommend wide resection of the primary site, which proved effective in this case.

Immunohistochemistry in diagnostic dermatopathology

This article briefly reviews many immunohistochemical stains that have been in use for years, emphasizing their diagnostic use and potential pitfalls. Several newer immunostains are described in a more comprehensive fashion, including brief summaries from recently published studies.