Merkel cell carcinoma

Bcl-2 antisense oligonucleotides (G3139) inhibit Merkel cell carcinoma growth in SCID mice

Merkel cell carcinoma was first described in 1972 by Toker and is an aggressive neuroendocrine skin tumor with a high metastatic potential. Merkel cell carcinoma is thought to derive from the neuroendocrine (Merkel) cells of the skin, although in contrast to fetal and especially adult Merkel cells, Merkel cell carcinomas express high levels of the Bcl-2 oncoprotein. Bcl-2 is capable of blocking programmed cell death and has been shown to play an important role in normal cell turnover, tumor biology, and chemoresistance. High Bcl-2 expression leading to prolonged survival of cells may therefore be of importance in the biological and clinical characteristics of Merkel cell carcinoma. In a SCID mouse xenotransplantation model for human Merkel cell carcinoma, we investigated the influence of the bcl-2 antisense oligonucleotide G3139 (Genta) on tumor growth in comparison with control oligonucleotides or cisplatin. Bcl-2 antisense treatment, targeting the first six codons of the bcl-2 mRNA, resulted in either a dramatic reduction of tumor growth or complete remission, whereas reverse sequence and two-base mismatch control oligonucleotides or cisplatin had no significant antitumor effects compared with saline-treated controls. Apoptosis was enhanced 2.4-fold in the bcl-2 antisense treated tumors compared with the saline-treated group, and no other treatment showed a comparable increase in apoptosis. Our findings suggest that bcl-2 antisense treatment may be a novel approach to improve treatment outcome of human Merkel cell carcinoma.

Intraepidermal Merkel cell carcinoma with no dermal involvement

Cutaneous Merkel cell carcinoma (MCC) typically involves the dermis. Less than 10% of MCC have epidermal involvement. Only one MCC confined exclusively to the epidermis has been previously reported but was not recognized until the lesion recurred with typical MCC in the dermis. We present a case of a wholly intraepidermal pagetoid MCC without dermal involvement in a 74-year-old man with a 2.0-cm solitary verrucous papule on the left index finger. The initial biopsy and complete excision specimens showed marked epidermal hyperplasia, focal prominent squamous cell atypia, and MCC with florid pagetoid spread through the epidermis. There was no evidence of tumor within the dermis. The pagetoid MCC tumor cells showed diffuse cytoplasmic staining with antibodies to cytokeratin 20, and negative staining for chromogranin, neurofilament, S-100, vimentin, HMB45, leukocyte common antigen, and CD3. The cell of origin of MCC is still debated. The existence of an entirely intraepidermal variant of MCC would lend support to the view that MCC is a neoplastic expression of Merkel cells in at least some cases. Dermal-based MCC is a high-grade primary cutaneous neoplasm, but MCC confined exclusively to the epidermis may have a better prognosis.

Unusual presentation of a Merkel cell carcinoma

Merkel cell carcinoma (MCC) is an uncommon, potentially lethal, cutaneous tumor that mainly occurs in sun-exposed skin of the head and neck area of the elderly. We report a case of MCC presenting as a 2-mm crusted erosion on the nose of an elderly patient, the smallest MCC reported thus far in the literature. The optimal management of MCC has not been clearly established. In view of its high local recurrence rate, predilection to metastasis, and significant mortality, aggressive treatment has been advocated. Identification of this tumor at such a small size posed a management dilemma because of lack of prospective treatment data involving biologic markers of prognostic significance for MCC.

Mutation analysis of P73 and TP53 in Merkel cell carcinoma

The p73 gene has been mapped to 1p36.33, a region which is frequently deleted in a wide variety of neoplasms including tumours of neuroectodermal origin. The p73 protein shows structural and functional homology to p53. For these reasons, p73 was considered as a positional and functional candidate tumour suppressor gene. Thus far, mutation analysis has provided no evidence for involvement of p73 in oligodendrogliomas, lung carcinoma, oesophageal carcinoma, prostatic carcinoma and hepatocellular carcinoma. In neuroblastoma, two mutations have been observed in a series of 140 tumours. In view of the occurrence of 1p deletions in Merkel cell carcinoma (MCC) and the location of p73 we decided to search for mutations in the p73 gene in five MCC cell lines and ten MCC tumours to test potential tumour suppressor function for this gene in MCC. In view of the possible complementary functions of p73 and TP53 we also examined the status of the TP53 gene. Sequence analysis of the entire coding region of the p73 gene revealed previously reported polymorphisms in four MCCs. In one MCC tumour, a mis-sense mutation located in the NH2-terminal transactivation region of the p73 gene was found. These results show that p73, analogous to neuroblastoma, is infrequently mutated in MCC. This is also the first report in which the role of TP53 in MCC has been investigated by sequencing the entire coding region of TP53. TP53 mis-sense mutations and one non-sense mutation were detected in three of 15 examined MCCs, suggesting that TP53 mutations may play a role in the pathogenesis or progression of a subset of MCCs. Moreover, typical UVB induced C to T mutations were found in one MCC cell line thus providing further evidence for sun-exposure in the aetiology of this rare skin cancer.

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.

Merkel's cell carcinoma in organ recipients: report of 41 cases

In the general population Merkel's cell carcinoma (MCC) is an aggressive neuroendocrine skin cancer. More than 600 cases have been reported. MCC seems to be common in transplant recipients, with 41 cases being reported to the Cincinnati Transplant Tumor Registry, and another 11 in the transplant literature. In the general population, it is a disease of older adults, with only 51% of cases occurring below the age of 50 years. In transplant patients, the mean age at diagnosis was 53 (range 33-78) years, and 29% of recipients were <50 years old. The tumor appeared from 5 to 286 (mean 91.5) months after the transplant. Of 44 lesions that occurred in 41 patients, the distribution was similar to that seen in the general population, with 36% occurring on the head and neck, 32% on the upper extremities, 16% on the trunk, 9% at unknown sites, and 7% on the lower extremities. Twenty of the patients (49%) had 22 other malignancies, the great majority of which (91%) were other skin cancers. Treatment depended on the stage of the disease and included wide surgical excision, radical lymph node dissection, radiation therapy, and chemotherapy. In transplant patients, MCC probably proved to be more aggressive than in the general population in that 68% of patients developed lymph node metastases and 56% died of their malignancies. Furthermore, one third of surviving patients still have active cancers from which they may die. Also, follow-up of survivors has been relatively short, with a mean of only 18 (range 0-135) months.

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.

Chemotherapy for patients with locally advanced or metastatic Merkel cell carcinoma

BACKGROUND

Merkel cell carcinoma (MCC) is a highly malignant skin neoplasm. Regional lymph node and distant metastasis occur in 20-52% of patients. The role of chemotherapy in the treatment of patients with this rare tumor is unclear.

METHODS

An exhaustive analysis of the literature (1980-1995) describing chemotherapy for patients with locally advanced or metastatic MCC was performed. All available published medical records (n = 101 patients) were entered in a database. In addition, data on six additional patients given chemotherapy during this time frame in Lyon, France, were included in the database.

RESULTS

For the 107 patients, the overall objective response rate to first-line chemotherapy was 61% (61 of 101 evaluable patients). The response rate was 57 % (41 of 72) for patients with metastasis and 69% (20 of 29) for patients with locally advanced tumors. No clinical parameter was found to be correlated to response to chemotherapy. A high rate of toxic death during first-line treatment (n = 7.7%) was reported for these patients. The median overall survival from the date of chemotherapy initiation was 9 months for patients with metastasis and 24 months for patients with locally advanced tumors. The projected overall survival at 3 years was 17% for patients with metastasis and 35% for patients with locally advanced tumors. Progression after first-line chemotherapy was associated with significantly worse survival for patients with metastasis. Rates of response to second-line (n = 33) and third-line (n = 10) chemotherapy were 45% and 20%, respectively.

CONCLUSIONS

MCC is chemosensitive but rarely chemocurable in patients with metastasis or locally advanced tumors. A high incidence of toxic death due to chemotherapy is reported in the literature.

Cytokeratin 20: a marker for diagnosing Merkel cell carcinoma

Merkel cell carcinoma is an aggressive cutaneous neoplasm that is often difficult to diagnose because of its histologic and immunohistochemical similarity to metastatic oat cell carcinomas and other cutaneous neoplasms. Our purpose was to determine the utility of immunoperoxidase staining of cytokeratin 20 (CK 20), a newly discovered intermediate filament protein, in Merkel cell carcinomas and other cutaneous tumors. Sixty-one tumors were sectioned and stained with antibodies directed at CK 20. The staining of Merkel cell carcinomas was compared with metastatic oat cell carcinomas, lymphomas, squamous cell carcinomas, basal cell carcinomas, melanomas, metastatic carcinoids, spiradenomas, eccrine carcinomas, adenoidcystic carcinoma, sebaceous carcinomas, hidradenomas, sebaceous epitheliomas, trichoblastomas, mixed tumors, and metastatic adenocarcinomas. Nine of 10 Merkel cell carcinomas stained with antibody to CK 20. Two metastatic carcinomas to the skin were also positive. One hidradenoma and one squamous carcinoma exhibited focal staining, but were otherwise negative. All other tumors were nonstaining. Cytokeratin 20 is a sensitive and specific marker for Merkel cell carcinoma and is helpful in distinguishing between Merkel cell carcinoma and other malignant and benign neoplasms.

Merkel cell carcinoma: spontaneous resolution and management of metastatic disease

BACKGROUND

Merkel cell carcinoma (MCC) is a rare, aggressive, cutaneous neoplasm. The primary form of initial treatment is wide surgical excision. The use of Mohs micrographic surgery as the primary form of treatment in MCC has been controversial. The course of MCC is often aggressive, with early metastasis, widespread disease, and death. Despite the poor prognosis, spontaneous regression has occasionally been reported.

OBJECTIVE

We describe the clinical course of two patients with Merkel cell carcinoma who underwent treatment with Mohs micrographic surgery for the primary MCC. Metastases were excised in the first case and spontaneously regressed in the second. Both patients are without clinical disease at the time of this report.

METHODS

Histopathology, clinical records, and the current literature are reviewed.

RESULTS

One patients was without recurrence of MCC for 13 years of follow-up. The other patient experienced clinical spontaneous remission after nodal spread of the disease, with no recurrence for 18 months after clinical remission and 24 months after surgery.

CONCLUSION

The treatment of Merkel cell carcinoma with Mohs micrographic surgery (MMS) has been successful for the control of primary skin disease, and is at least comparable to wide excision. Spontaneous regression may occur in the course of this usually relentless and aggressive disease. The explanation for spontaneous regression of MCC is unknown.

Surgical management of Merkel cell carcinoma

OBJECTIVES

To characterize the natural history of Merkel cell carcinoma (MCC) and to analyze the influence of patient, tumor, and treatment-related variables on survival and recurrence.

SUMMARY BACKGROUND DATA

Approximately 425 cases of MCC have been described in the literature. This study represents the largest experience reported.

METHODS

A review was performed of patients who had been treated at Memorial Sloan-Kettering Cancer Center for MCC between 1969 and 1996. Follow-up data were available for 102 of the 109 (94%) patients identified.

RESULTS

The overall 5-year disease-specific survival rate was 74%. The median follow-up was 35 months. For all patients, the only independent predictor of survival was the tumor stage at presentation. For patients with stage I disease, the tumor size at presentation was also an independent predictor of survival. Recurrence of disease occurred in 55 patients (55%), and the most common site of first recurrence was within the draining lymph nodes (n = 35). Elective lymph node dissection was the only parameter independently predictive of improved relapse-free survival. The overall disease-specific survival rate after recurrence was 62%. Predictors of improved disease-specific survival after recurrence included nodal as compared to local or distant recurrence, the ability to render the patient free of disease after recurrence, and a disease-free interval of >8 months.

CONCLUSION

The prognosis for patients with MCC is favorable, and even after recurrence the majority of patients experience long-term survival. Incorporation of size into the staging system more accurately predicts survival in patients with stage I disease. Although elective lymph node dissection decreased the rate of recurrence, it was not associated with improved overall survival.

Recognition and management of high-risk cutaneous tumors

The majority of cutaneous malignancies can be treated by the military dermatologist in a clinical setting. Recognition of tumors at high risk for recurrence or metastasis is important for any dermatologist but especially list care. Providing optimal care includes knowledge about which patients should be medavacced to larger medical centers for advanced surgical and medical treatments.

Merkel cell carcinoma of the skin

Merkel cell carcinoma is a rare, aggressive neuroendocrine tumor of the skin with a predisposition for local regional and distant spread. Radiotherapy after wide local excision has improved local control, but distant spread continues to be a significant problem. This is an update of our experience in the treatment of Merkel cell carcinoma at the University of Florida. Of 24 patients who were treated for Merkel cell carcinoma between 1984 and 1996, 18 patients were treated at the time of the initial diagnosis, and six were treated after local-regional recurrence. Of the 18 previously untreated patients, 13 had primary sites in the head and neck region, and five had primary sites elsewhere. Minimum follow-up was 1 year; no patient was lost to follow-up. The 5-year absolute survival, cause-specific survival, and local-regional control rates for the entire group were 27%, 31%, and 78%, respectively. Patients who were treated with radiotherapy at the time of initial presentation had 5-year absolute survival, cause-specific survival, and local-regional control rates of 38%, 44%, and 73%, respectively. Most deaths were due to distant metastasis. Site of the primary tumor (head and neck versus other) was not associated with any difference in the outcome. Of six patients who were treated at the time of local-regional recurrence, five developed distant metastasis at 3-19 months (median 8 months) from the time of treatment. One patient was alive and without evidence of disease 13 months after treatment. All patients who were treated at the time of local-regional recurrence had local-regional control after radiotherapy at 3-30 months (median 8 months). Wide local excision and radiotherapy is effective local-regional treatment for Merkel cell carcinoma of the skin, but distant metastasis remains a significant problem in this disease. The role and effectiveness of chemotherapy as part of the initial treatment remains to be defined.

Unusual cutaneous malignancies

The most commonly occurring cutaneous malignancies are basal cell and squamous cell carcinoma. There are, however, other rare malignancies that are encountered and should be included in the differential, in which both the clinical and the histological diagnosis may be difficult. Here, the clinical and histological features, management, and prognostic factors of merkel cell carcinoma, microcystic adnexal carcinoma, leiomyosarcoma, dermatofibrosarcoma protuberans, and angiosarcoma are reviewed.

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.

Merkel cell carcinoma in a renal transplant patient: increased incidence?

The identification of malignancies associated with transplantation has led to enhanced vigilance and care in these patients, as well as insight into the pathogenesis of select malignancies. We report a case of Merkel cell carcinoma, an uncommon cutaneous malignancy of neuroendocrine origin, diagnosed in a 65-year-old Caucasian man 6 years after renal transplantation. While it is well known that transplant patients are at increased risk for squamous cell carcinomas of the skin, other types may also have an increased frequency. We suggest that Merkel cell carcinoma could have an increased incidence in the transplant population.

Fine-needle aspiration of Merkel cell carcinoma of the skin with cytomorphology and immunocytochemical correlation

Merkel cell carcinoma (MCC) of the skin is a rare, primary malignant skin neoplasm which can present as a cutaneous nodule. These neoplasms are seen primarily in the elderly and located in the head and neck area or extremities. Twenty-nine aspirates from primary and metastatic lesions obtained by percutaneous fine-needle aspiration in 19 patients have been studied. The cytomorphologic features, clinical information, and immunocytochemical (ICC) findings are detailed. Aspirate smears demonstrated small-to-intermediate-sized cells with a loosely cohesive pattern. Nuclei were round with finely granular chromatin and multiple, small nucleoli. Cells possessed a thin rim of cytoplasm, and infrequent pseudorosette formations were noted in cell groups. ICC results were universally positive for cytokeratin, which showed a paranuclear "dot-like" pattern. Neuron-specific enolase, epithelial membrane antigen, and S-100 protein were positive in varying degrees. Leukocyte common antigen was universally negative. The diagnosis of MCC of the skin by FNA can be made by applying cytologic features in addition to ancillary studies and clinical information.

Localized limb cutaneous metastases

Cutaneous metastatic disease may be evident in a variety of forms and locations. Anatomically, it may on occasion be confined as localized limb metastases. We report on two patients with localized limb metastases, one from melanoma and the other from Merkel cell carcinoma. Patients with localized limb metastasis have a poor prognosis; however, treatment options not available for generalized cutaneous metastatic disease, such as amputation or isolated limb perfusion with chemotherapeutic agents, can be at times be beneficially employed.

Small cell sweat gland carcinoma in childhood

Sweat gland carcinomas are rare skin tumors that typically occur in older patients. The spectrum of their clinical and pathologic features is broad, and many different types of sweat gland carcinomas have been described, ranging from fairly indolent to highly aggressive neoplasms. We present two cases of sweat gland carcinoma with a predominant small cell morphology. Both tumors occurred in children. One lesion developed in an 8-year-old girl as an asymptomatic papule on her left forearm, which ultimately was evaluated using biopsy because of rapid growth and change in color. The other lesion occurred on the hand of a 12-year-old boy. Both tumors were pandermal and extended into fat. They were composed of monotonous cuboidal cells with scant cytoplasm that formed tubules and grew in anastomosing cords and trabeculae. The tumor cells were immunoreactive for cytokeratins but not for cytokeratin 20. Ultrastructural analysis (available in one case only) showed that the tumor cells lacked neurosecretory granules. This variant of sweat gland carcinoma needs to be distinguished from other small cell neoplasms of the skin, especially Merkel cell carcinoma, its closest mimic.

Merkel cell carcinoma: report of three cases

Three cases of Merkel cell carcinoma are reported: Case 1 on the upper eyelid with regional lymph node metastasis, Case 2 with spontaneous regression after repeated biopsies, and Case 3 presumably developing on the lesion of pre-existing Bowen's disease. In Case 2, the biopsy specimen was characterized by numerous apoptotic cells in the periphery of the tumor nests surrounded by lymphocytic infiltration. In Case 3, the tumor developed after injury to the pre-existing lesion of Bowen's disease.

Status of cytokine and antigen presentation genes in Merkel cell carcinoma of the skin

BACKGROUND

Merkel carcinoma (MCC) of the skin is an aggressive form of skin cancer, morphologically demonstrating both epithelial and neuroendocrine properties. However, little is known about its molecular characteristics.

OBJECTIVE

The aims of the study were to explore growth characteristics and immune responses of MCCs at the molecular level.

METHODS

A reverse transcription-polymerase chain reaction (RT-PCR) technique was employed to study those parameters in biopsies of MCCs and their adjacent areas.

RESULTS

Analyzing mRNA levels of various epithelial genes (c-myc, cdc2 kinase, E2F, PCNA, p53, and RB, cytokeratins 5 and 10) we concluded that MCCs express markers of epithelial hyperproliferation together with markers of neuroendocrine differentiation (NSE). On the other hand, there is a lack of cytokines (IL-2, IFN-g) typical for a specific, T cell-mediated immune response in MCCs. However, several cytokines (e. g., IL-12) are produced that are required for the initial steps of that type of immune response.

CONCLUSION

The epithelial hyperproliferation and impaired local immune responses might contribute to the aggressive behaviour of the tumour.

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.

Early aggressive treatment for Merkel cell carcinoma improves outcome

BACKGROUND

Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine tumor of dermal origin. Treatment recommendations are limited owing to a paucity of retrospective data and an absence of prospective data. The objective of this study was to determine current therapeutic trends and their impact upon outcome.

METHODS

A retrospective study (1983 to 1996) was performed with patients from the Department of Defense and our University-affiliated hospitals.

RESULTS

Thirty-five patients were evaluated with a mean follow-up of 31 months. Overall, 1- and 2-year survival rates were 80% and 50%, respectively. Patients undergoing wide local excision, prophylactic lymph node dissection, and adjuvant radiotherapy had significantly decreased locoregional and distant recurrence rates and improved survival when compared with their counterparts. Adjuvant chemotherapy did not diminish recurrence rates nor improve survival. Both locoregional and distant recurrence significantly decreased survival.

CONCLUSIONS

These data suggest that early aggressive treatment for MCC improves both tumor control and survival, whereas the early use of chemotherapy does not improve outcome.

Merkel cell carcinoma arising after therapeutic immunosuppression

Azathioprine and cyclosporin have been used as immunosuppressants for many years, but long-term use has also been associated with neoplasia. We report three cases of rapidly fatal Merkel cell carcinoma in patients who had been treated with azathioprine for many years either for rheumatoid arthritis or following organ transplantation. Two of these patients had also received cyclosporin. We suggest that Merkel cell carcinoma may be seen more commonly in immunosuppressed patients than in the normal population and that the oncogenic potential of azathioprine and cyclosporin should be borne in mind when prescribing these drugs.

Merkel cell carcinoma and multiple Bowen's disease: incidental association or possible relationship to inorganic arsenic exposure?

An 81-year-old Japanese male was referred to our clinic in 1991 with multiple Bowen's disease. The associated hyperpigmentation of the trunk and extremities and palmoplantar keratotic nodules indicated that he had suffered from chronic arsenic poisoning. Interestingly, he was a native of Namikata in Ehime, Japan, where many residents have suffered from multiple Bowen's disease with internal malignancy. Arsenic exposure was strongly suspected. Two years later, Merkel cell carcinoma developed on the dorsum of his right hand, where Bowen's disease lesions were absent. Metastasis of this Merkel cell carcinoma led to his eventual death one year later. To our knowledge, this is the first report of Merkel cell carcinoma associated with multiple Bowen's disease. Chronic arsenic poisoning may be responsible for the association of these two rare skin neoplasms.

Atypical, severe toxoplasmic retinochoroiditis in elderly patients

BACKGROUND

The diagnosis of toxoplasmic retinochoroiditis is based primarily on characteristic ocular findings, with supportive serologic evidence. Clinical recognition of atypical presentations is critical for timely antiparasitic drug therapy.

METHODS

Case histories were reviewed for seven presumed immunocompetent elderly patients with atypically severe (multifocal or diffuse or both) toxoplasmic retinochoroiditis. Three cases initially were misdiagnosed as acute retinal necrosis syndrome. The correct diagnosis was confirmed in each case by response to antiparasitic drug therapy, polymerase chain reaction studies of intraocular specimens, or histopathologic analysis.

RESULTS

The patients ranged in age from 69 to 82 years (median, 74 years). Only three patients had intercurrent medical conditions that may be associated with subtle immune dysfunction (diabetes mellitus and hepatitis C). The extensive necrotizing retinochoroiditis in each patient was nonhemorrhagic and not associated with occlusive retinal arteritis. Despite prompt response to antiparasitic drug therapy, prolonged treatment usually was required, and four patients had retinitis reactivation after discontinuing treatment. Significant visual loss accompanied the infection in most eyes.

CONCLUSION

Toxoplasmosis should be considered as a cause of multifocal or diffuse necrotizing retinitis or both in elderly patients. Older patients may be more susceptible to severe ocular Toxoplasma infections because of age-related decline in cell-mediated immunity and chronic underlying diseases.

[Merkel cell carcinoma: primary cutaneous neuroendocrine tumor]

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

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.

Chromosome 6 trisomy as sole anomaly in a primary Merkel cell carcinoma

We present a case of Merkel cell carcinoma of the thigh diagnosed by conventional histology, immunohistochemistry, electron microscopy and cytogenetics. A unique chromosome 6 trisomy characterized this primary neoplasm, as confirmed by FISH study. The role of chromosome analysis and interphase cytogenetics is emphasized as an adjunct in the subtyping of tumours and their prognostic evaluation.

Merkel cells and Merkel cell carcinoma express the BCL-2 proto-oncogene

The bel-2 proto-oncogene, which is involved in the regulation of apoptosis, is expressed in a wide variety of fetal and adult tissues. We and others have demonstrated recently that in the human skin melanocytes, nevus cells and melanoma cells express bcl-2 constitutively. In the present study, we have analysed the expression of bcl-2 in Merkel cells and in Merkel cell carcinomas. In 2 colour immunofluorescence staining, normal human Merkel cells as identified by the expression of cytokeratins 8, 18 and 20, were also anti-bcl-2 positive. Staining of paraffin sections of Merkel cell carcinomas with an anti-bcl-2 monoclonal antibody revealed strong bcl-2 protein immunoreactivity in all 5 tumors tested. Serial sections of Merkel cell carcinomas stained with the monoclonal antibodies CK 20, CAM 5.2, anti-neuron-specific enolase and anti-bcl-2 showed that the anti-bcl-2 reactive cells were indeed tumor cells. Our data demonstrate for the first time, that normal human Merkel cells and Merkel cel carcinomas express bcl-2 constitutively. Considering the biological function of the bcl-2 proto-oncogene, i.e., its anti-apoptotic effect, it is conceivable that in the near future, modulations of the expression of this protein may offer a new strategy in the therapy of bcl-2 expressing tumors such as Merkel cell carcinoma.

Office radiotherapy in dermatology: a contemporary perspective

Ionizing radiation was recognized very early after its discovery as a useful weapon against both neoplasia and inflammation. Following an initial period of enthusiastic use, recognition of its drawbacks and the development of safe and effective alternative treatments for many applications have resulted in a marked reduction in the use of radiotherapy in most dermatological offices. Nonetheless, this modality remains an important component of our modern therapeutic armamentarium. It is a treatment of choice in some situations, and a useful alternative in many more. A thorough understanding of the principles and practice of safe radiotherapy remains vital to the full practice of dermatology in 1996. The present review summarizes the current practice of radiotherapy and offers some guidelines for safe and effective use of this important tool. Detailed discussions of radiobiology, deep radiotherapy (DXRT) and electron beam (EB) therapy are beyond the scope of this clinical review.

Differences of bcl-2 protein expression between Merkel cells and Merkel cell carcinomas

The bcl-2 gene, originally identified in B-cell lymphomas, encodes for proteins which may assume oncogenic functions by blocking apoptosis. Bcl-2 proteins are broadly distributed among various tissues, including epithelial ones. Within the skin, bcl-2 is strongly expressed in melanocytes, but its further distribution is yet unclear. The Merkel cells, neuroendocrine-epithelial cells of the skin, are present within the epidermis and hair follicles, mostly nerve-associated, and are believed to be postmitotic and long lived. Possibly they give rise to the malignant Merkel cell carcinomas. In the present study we investigated the bcl-2 expression on the protein level by means of immunohistochemical techniques including double confocal laser scanning microscopy, as well as on the RNA level by RT-PCR techniques, in Merkel cells, Merkel cell carcinomas, and cell lines. Merkel cells were identified by double staining for cytokeratins 20 or 8/18. We demonstrate that fetal epidermal and dermal Merkel cells are immunostained for bcl-2 protein, most of them clearly weaker than melanocytes. Adult Merkel cells also express bcl-2 protein very heterogeneously, mostly weak. In contrast, Merkel cell carcinomas are usually strongly positive for bcl-2 protein with some degree of heterogeneity. This is different from malignant melanomas in which bcl-2 expression is reduced as compared to normal melanocytes. Bcl-2 gene expression was also shown for Merkel cell carcinoma cell lines on both the mRNA and the protein level. Possibly bcl-2 protein expression is downregulated during the life span of Merkel cells, arguing that they may succumb to a certain cell turnover. The comparably high bcl-2 protein level in Merkel cell carcinomas may reflect peculiar biological and clinical characteristics.

Merkel cells and Merkel cell carcinoma express the BCL-2 proto-oncogene

The bcl-2 proto-oncogene, which is involved in the regulation of apoptosis, is expressed in a wide variety of fetal and adult tissues. We and others have demonstrated recently that in the human skin melanocytes, nervus cells and melanoma cells express bcl-2 constitutively. In the present study, we have analysed the expression of bcl-2 in Merkel cells and in Merkel cell carcinomas. In 2 colour immunofluorescence staining, normal human Merkel cells as identified by the expression of cytokeratins 8, 18 and 20, were also anti-bcl-2 positive. Staining of paraffin sections of Merkel cell carcinomas with an anti-bcl-2 monoclonal antibody revealed strong bcl-2 protein immunoreactivity in all 5 tumors tested. Serial sections of Merkel cell carcinomas stained with the monoclonal antibodies CK 20, CAM 5.2, anti-neuron-specific enolase and anti-bcl-2 showed that the anti-bcl-2 reactive cells were indeed tumor cells. Our data demonstrate for the first time, that normal human Merkel cells and Merkel cell carcinomas express bcl-2 constitutively. Considering the biological function of the bcl-2 proto-oncogene, i.e., its anti-apoptotic effect, it is conceivable that in the near future, modulations of the expression of this protein may offer a new strategy in the therapy of bcl-2 expressing tumors such as Merkel cell carcinoma.

Merkel cell carcinoma

BACKGROUND

Merkel cell carcinoma is an aggressive tumor with nonspecific clinical features. The prognosis in general is worse than malignant melanoma. Local recurrence rates are high with one-third of patients having recurrence within one year of excision. The tumor invades blood vessels and lymphatics. This frequent lymphatic dissemination leads later to satellite lesions and recurrence. Distant metastases occur in one-third of patients. One-,two- and three-year survival rates are poor, being estimated at 88%, 72%, and 55%, respectively.

OBJECTIVE

To increase awareness of the behavior of this uncommon tumor.

METHODS

A review of the current literature and recommendations regarding this tumor.

RESULTS

Wide local excision with 3-cm margin shows significant reduction in local recurrence compared with 2-cm margins. Two-thirds of patients with local recurrence ultimately die from their disease. Radiation therapy has a role to play in the local and regional clearance of the tumor.

CONCLUSION

Prompt diagnosis and surgical excision are necessary to improve survival. Mohs micrographic surgery offers potential advantages in evaluating both the lateral and the deep margins. Follow-up studies of patients treated with this modality will be beneficial.

Neurochemical markers in human cutaneous Merkel cells. An immunohistochemical investigation

Merkel cells (MCs) are specialized sensory cells widely distributed in the epithelia of vertebrates. A variable immunohistochemical pattern of neuronal and neurotransmitter markers has been demonstrated in MCs of several species including man. In the present study, we investigated the expression of neurochemical markers in a selected population of human cutaneous MCs by immunofluorescence. The structural neural proteins protein gene product 9.5 and neuron-specific enolase were found to be the most reliable markers for MC identification. Moreover, neurofilament immunoreactivity was shown in a small subset of epidermal MCs. Among the neurotransmitter markers, evidence for expression of calcitonin gene-related peptide, vasoactive intestinal polypeptide, peptide histidine isoleucine amide, neuropeptide Y, neurokinin A, galanin, substance P, somatostatin and phenylethanolamine N-methyltransferase was found. These immunoreactivities were highly variable as far as number of positive cells and staining intensity were concerned. The results indicate that a complex and heterogeneous immunophenotype can be expressed even within a homogeneous population of human MCs.

Merkel cell carcinoma. Diagnosis and treatment

BACKGROUND

Merkel cell carcinoma is an uncommon malignancy of the skin that often portends a poor prognosis. Since its first description by Toker in 1972, a plethora of case reports and articles regarding the etiopathogenesis and treatment have been published spanning multiple medical and surgical disciplines. Much confusion still exists regarding the diagnosis and treatment of this ominous tumor.

OBJECT

Through extensive review of the medical, surgical, and pathological literature, to collate the observations of multiple investigators and summarize these findings.

METHODS

Articles from journals of multiple subspecialties were carefully reviewed with particular emphasis placed on epidemiology, prognosis, histology, immunohistochemistry, electron microscopy, tumor origin, treatment, and work-up of Merkel cell carcinoma.

RESULTS

Merkel cell carcinoma is an aggressive malignant neoplasm. Local recurrence develops in 26-44% of patients despite therapy. Up to three-fourths of patients eventually develop regional nodal metastases with distant metastases occurring in one-third of all patients. Reported overall 5-year survival rates range from 30% to 64%.

CONCLUSION

Treatment recommendations unfortunately are based more on anecdotal than scientific data because of the rarity of the tumor and its recognized high risk. Most authors recommend wide local excision of the primary lesion and regional lymph node resection if lymph nodes are palpable followed by x-irradiation of both the postsurgical bed and lymph node basin. The role of elective lymph node resection in the absence of clinically positive nodes remains controversial.

Penile Merkel cell carcinoma

Merkel cell carcinoma of the genitalia is very rare and to date has been found only in vulvar mucosa. We describe an aggressive Merkel cell tumor in the frenulum of the penis with lymph node metastases, local recurrence, and eventually widespread dissemination. The primary tumor was associated with discontiguous squamous cell carcinoma in situ. This is the first report of Merkel cell (neuroendocrine) carcinoma in this anatomic site.

Expression of alpha subunit of guanine nucleotide-binding protein Go in Merkel cell carcinoma

The alpha subunit of guanine nucleotide-binding protein Go (Go alpha), which was initially isolated from bovine brain, interacts with muscarinic cholinergic receptors and regulates neuronal calcium channels. Go alpha is known to be localized in neural tissues, some endocrine cells, and neuroendocrine tumors. We have immunohistochemically investigated the expression of Go alpha in 4 cases of Merkel cell carcinoma using the method of microwave treatment. In all cases of Merkel cell carcinoma, Go alpha was consistently detected on the plasma membrane and cytoplasm of the tumor cells. Nerve fibers in the skin were also positive for Go alpha, but other epidermal or dermal components such as keratinocytes, melanocytes, fibroblasts, or lymphoid cells were negative. Tumor cells of squamous cell carcinoma, cutaneous lymphoma, sweat gland carcinoma, and malignant melanoma were negative for Go alpha. The present study indicates that Go alpha may be a useful immunohistochemical marker of Merkel cell carcinoma.

Therapy for paraneoplastic neurologic syndromes in six patients with protein A column immunoadsorption

BACKGROUND

Paraneoplastic neurologic syndromes, although rare, cause significant morbidity and mortality. They are thought to be immunologically mediated, but to date those involving the central nervous system (CNS) have not been particularly responsive to immunologic therapy. The use of the novel immunomodulator, protein A immunoadsorption, was explored to address this question.

METHODS

Six patients with neurologic paraneoplastic syndromes were treated with this technique, using the "off line" method. Two hundred fifty ml of plasma was perfused through a column containing protein A covalently attached to a silica matrix. The plasma was then returned to the patient.

RESULTS

Five of the patients responded to the therapy, with complete and durable responses in three patients with opsoclonus-myoclonus, objective, though transient, improvement in one patient with paraneoplastic brainstem encephalitis associated with a Merkel cell tumor, and stabilization and partial improvement in one patient with paraneoplastic limbic encephalitis. The patient without response developed a cutaneous vasculitis after the second treatment, and therapy was discontinued.

CONCLUSIONS

This therapy appears beneficial for a number of paraneoplastic syndromes, most dramatically in the opsoclonus/myoclonus syndrome.