Merkel cell tumour: report of a case

An isolated Merkel cell carcinoma metastasis at a distant cutaneous site presenting as a second 'primary' tumor

Merkel cell carcinoma (MCC) is an aggressive neuroendocrine carcinoma of the skin. Disease progression usually occurs via lymphatic spread to regional lymphatic draining basins, followed by distant metastasis. We report the clinical course, histopathology and genetic analysis of a 69-year-old woman with likely hematogenous spread of cutaneous neuroendocrine carcinoma manifesting as a single metastatic lesion to a distant cutaneous site. Although the possibility of two cutaneous primary MCCs was considered, array comparative genomic hybridization (aCGH) identified identical distal amplification of a region of chromosome 12p, and synchronous loss of chromosomes 8p and 17p, effectively ruling out the possibility of independent primaries. We propose that this represents a primary cheek MCC with rapid, isolated cutaneous metastasis to the contralateral ankle via hematogenous spread. The distinction between a second primary MCC and a distant cutaneous metastasis clearly has important implications with regard to staging, treatment and prognosis. To our knowledge, this represents the first report of the use of aCGH to clarify the relationship of multiple synchronous cutaneous MCCs and the first report of a single distant cutaneous focus of hematogenous spread. Our data calls into question prior reports alleging multiple cutaneous primaries of this very rare tumor.

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.

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.

Giant neuroendocrine (Merkel cell) carcinoma of the skin

An 82-year-old woman had a dark red to purple tumor on the left buttock that had gradually enlarged during the last 5 years. Although routine histologic examination was not sufficient for diagnosis, neuroendocrine carcinoma was diagnosed by immunohistochemical and ultrastructural studies. Immunohistochemical-positive reactions to neurofilament, cytokeratin, neuron-specific enolase, and epithelial membrane antigen were noted. Electron microscopically, membrane-bound, dense core granules that yielded a positive uranaffin reaction and intermediate filaments in the perinuclear area were observed in the cytoplasm of most tumor cells. Desmosome-like structure between them was also found. Approximately 6 months after local excision, metastatic lesions developed in the regional lymph nodes and liver.

Primary neuroendocrine carcinoma of the skin. Clinicopathologic study of 18 cases

The clinical and pathologic features of primary neuroendocrine carcinoma of the skin in 18 elderly patients are reported. The carcinomas arose in the dermis and subcutaneous tissues, particularly on the head and the upper extremities. One tumor occurred in an irradiated area. Using Gould's clinicopathologic classification, we have found four trabecular types, eleven intermediate cell types, and two small cell types. One tumor could not be classified. Other noteworthy pathologic features were association with invasive squamous cell carcinoma, lentiginous melanocytic hyperplasia, and presence of intratumoral melanocytes. Immunoreactivity for cytokeratins (56 kD), neurofilaments, neuron-specific enolase, and epithelial membrane antigen was observed. The paranuclear globular staining pattern of cytokeratins and neurofilaments was conspicuous. The ultrastructural features revealed paranuclear intermediate filament aggregates (fibrous bodies), neurosecretory granules, and cell junctions. In two metastatic tumors, high levels of catecholamines were found. The trabecular types were characterized by localized disease and a good prognosis. The patients with the small cell types died of distant metastases. Postoperative radiotherapy seemed to reduce the rate of local recurrences.

The Merkel cell and associated neoplasms in the eyelids and periocular region

Merkel cells are clear oval cells in the epidermis and outer root sheaths of hair follicles, which are probably of epithelial origin, share ultrastructural features with neuroendocrine cells, and are found in association with touch receptors. In the eyelid, they occur singly in the epidermis and external root sheaths of hairs and eyelashes, and in specialized touch spots alternating with eyelashes. Their typical electron microscopical and antigenic features include dense-core granules, intranuclear rodlets, spinous processes, and a positive reaction for specific cytokeratins, epithelial membrane antigen, neuron-specific enolase, chromogranin and synaptophysin. Merkel cell carcinoma probably develops from precursor cells which give rise to keratinocytes and Merkel cells, and nearly one out of ten Merkel cell carcinomas occur in the eyelid and periocular region. They tend to be bulging lesions near the lid margin of elderly patients, reddish in color, and erythematous with telangiectatic vessels. The diagnosis is based on the frequent presence of neurofilaments and paranuclear aggregates of intermediate filaments in addition to features typical of normal Merkel cells. The tumor often mimics lymphoma or undifferentiated carcinoma and frequently invades lymphatic vessels. One third of Merkel cell carcinomas recur, almost two thirds give rise to regional node metastases, and up to one half metastasize widely and result in death. Initial treatment should be prompt and aggressive, with wide resection and routine postoperative irradiation. Although metastatic lesions often respond to radiation therapy and cytostatic drugs, these treatments are mainly of palliative value.

Cutaneous neuro-endocrine (Merkel cell) carcinoma

Two cases of neuro-endocrine (Merkel cell) tumours of the skin are reported. There was evidence of distant relapse in both patients who eventually succumbed to the disease. The wide range of clinical and radiological manifestations of this rare tumour are discussed and the literature reviewed.

Neuroendocrine carcinoma (Merkel cell tumor?) presenting as a subcutaneous tumor. An ultrastructural and immunohistochemical study of three cases

The clinical and pathological features of three unusual soft tissue tumors are presented. They occurred in the groin of elderly patients in the subcutaneous tissue. In Case 1, the inguino-crural tumor coexisted with a second mass in the pelvis. The tumors had a tendency to recur locally and to invade the regional lymph nodes. Metastatic dissemination of the disease resulted in the death of the patient in Case 3. Histologically, the tumors appeared composed of small round cells with scanty cytoplasms, arranged in diffuse, poorly cohesive or solid sheets. In places, a trabecular pattern was noted. Mitotic figures were numerous. Some cells exhibited argyrophil granules. The ultrastructural study revealed compact whorls of intermediate filaments and neurosecretory granules. All three cases displayed a paranuclear dot-like positive reaction with antibodies to cytokeratins and neurofilaments. A diffuse cytoplasmic immunostaining for neuron-specific enolase was present in Cases 1 and 2. Protein S-100, vimentin and leucocyte common antigen could not be demonstrated. All these characteristics, except for the subcutaneous location, are shared with neuroendocrine (Merkel cell) tumors of the skin.

Merkel-cell carcinoma of the pinna

Merkel-Cell carcinoma is a rare malignant skin tumour. It was first described as 'Trabecular Carcinoma' by Toker in 1972. Since then many reports have appeared in the literature, mainly in the dermatology, pathology and to a lesser extent, in the plastic surgery journals. Surprisingly, the topic is rarely discussed in the otolaryngology literature, though nearly fifty per cent of these tumours arise in the head and neck.

[Clinical aspects and therapy of Merkel cell tumor--report of 4 personal cases and review of the literature]

Four cases of Merkel cell tumor located in the face or on the trunk are presented. In a literature review 339 cases were found and analysed. The Merkel cell tumor is a neuroendocrine tumor of the skin derived from the Merkel cells. It is located most often in the face and neck area. Typically, it is an exophytic node, has a red-blue color and measures 25 mm in diameter on the average. Since it is metastasizing it is a malignant tumor. Regional node metastases were found in 27%, local recurrences occur in 51%, and distant metastases were seen in 32% of the cases. The best therapy is excision with wide margins as is the rule for a malignant skin tumor. While the tumor reacts to radiotherapy, chemotherapy seems to be of no help.

Neuroendocrine (Merkel cell) carcinoma of the skin. Its natural history, diagnosis, and treatment

Over 400 cases of neuroendocrine (Merkel cell) carcinoma of the skin (NCS) have been reported. This tumor continues to pose problems in diagnosis and effective treatment for physicians unfamiliar with its biological characteristics. Reported here are five additional cases of NCS and the literature for this rare neoplasm is comprehensively reviewed. An early and accurate diagnosis is made possible by combining clinical presentation with results of histologic study, immunoperoxidase staining for neuron-specific enolase (NSE), epithelial membrane antigen (EMA), cytokeratins, and electron microscopy. NCS is an aggressive tumor. Depending on the length of follow-up, up to 40% of tumors locally recur, 55% develop regional nodal metastases, and 36% undergo distant metastasis. Survival is sex, but not age, dependent, with an overall 2-year survival rate of 72% (males 58% vs. females 79%). No standard procedure for initial and/or follow-up treatment for NCS exists. The authors recommend that NCS be treated, whenever possible, using the same rationale as applied for the treatment of squamous cell carcinoma of the skin.

Epidermotropic primary neuroendocrine (Merkel cell) carcinoma of the skin with Pautrier-like microabscesses. Report of three cases and review of the literature

Three cases of primary cutaneous neuroendocrine carcinoma involving the face are reported. In the first patient the tumor developed in the scar of a previously excised basal cell carcinoma of the nose, recurred locally, and metastasized to a regional lymph node 2 1/2 years after initial treatment. In the second and third patients the tumors were located on the forehead and were removed with a wide excision. In the second patient the tumor metastasized to regional lymph nodes 1 month after treatment. Light microscopic examination in all patients showed an undifferentiated, small cell, dermal tumor with prominent epidermotropism, forming Pautrier-like microabscesses. Immunohistochemical staining for neuron-specific enolase was positive, and ultrastructural examination revealed numerous cytoplasmic neurosecretory granules and paranuclear aggregates of intermediate-sized filaments. The literature concerning epidermal involvement by primary neuroendocrine carcinoma of the skin is reviewed; the relation with basal cell carcinoma and treatment are discussed.

Cytokeratin and laminin immunostaining in the diagnosis of cutaneous neuro-endocrine (Merkel cell) tumours

Nine cutaneous neuro-endocrine tumours have been immunostained with monoclonal antibodies to low molecular weight cytokeratin (CAM 5.2) and neurofilament. Polyclonal antisera to neurone-specific enolase, calcitonin and laminin were also used. All nine cases showed paranuclear, dot-like positive staining with CAM 5.2 and diffuse cytoplasmic staining for neurone-specific enolase. Neurofilament and calcitonin immunoreactivity could not be demonstrated. All tumours were negative for laminin immunoreactivity. The limitations of staining for neurone-specific enolase are discussed and the value of CAM 5.2 in the differential diagnosis of cutaneous neuro-endocrine tumours is emphasized. The histogenetic implications of the absence of laminin staining are considered.

Primary small cell carcinoma of skin. Histogenetical study

Four cases of primary small cell carcinoma of the skin (PSCCS) are presented (ages ranging from 60 to 68 years). Ultrastructurally, two cell types were identified, with both presenting electron-dense secretory granules and paranuclear intermediate filaments. Argyrophylia was positive in one case. Intense solar elastosis in two cases and actinic keratosis in one case suggest a possible role from solar damage in the pathogenesis of this tumor. According to comparative ultrastructural features, different histogenetic possibilities in Merkel cells (MC), peripheral neuroblastic tissue, and totipotential cells are discussed. Some neurosecretory-like granules were observed in basal cell carcinoma (BCC). We consider that PSCCS reproduces cells similar to MC and probably originates in stem cells with totipotential capacity.

A study of intermediate filaments (cytokeratin, vimentin, neurofilament) in two cases of Merkel cell tumor

In two cases of Merkel cell tumor, the study of intermediate filaments, using monoclonal antibodies (vimentin, cytokeratin, neurofilaments), confirmed the double differentiation (neuroendocrine and epithelial) of this tumor as previously observed in histological, electron microscopical and histochemical analyses. Labelling of the tumor cells was positive with monoclonal antibodies against neurofilament proteins and cytokeratin.

Extrapulmonary oat cell carcinoma

Primary extrapulmonary tumors with histologic features indistinguishable from bronchogenic oat cell carcinoma are appearing with increasing frequency in the literature. These tumors have been described in the esophagus, stomach, pancreas, larynx, hypopharynx, salivary glands, nasal cavity and paranasal sinuses, thymus, small and large bowel, uterine cervix, endometrium, breast, prostate, urinary bladder, and skin. It is now widely believed that oat cell carcinoma is a poorly differentiated counterpart of carcinoid tumor and that both originate from an endocrine cell system. In this article, the authors review all cases of extrapulmonary oat cell carcinomas, which they were able to find in the English literature, and report personally studied examples of these tumors, occurring in the esophagus, stomach and urinary bladder. A closely related, if not identical, tumor arising in the skin is also described. It is emphasized that a wider recognition of these tumors is likely to lead to their more frequent diagnosis and possible treatment.

Multiple neuroendocrine carcinomas (so-called Merkel cell tumours) of the skin. Report on two cases with unique clinical course

Two neuroendocrine carcinomas of the skin (so-called Merkel cell tumours) are presented. In both cases multiple tumour nodules developed within the course of the disease. The light and electron microscopic observations correspond with the findings reported in other neuroendocrine carcinomas. As a variable morphological and clinical pattern for these tumours seems to exist we consider our two cases with their unique clinical picture to be an obviously infrequent variant of this tumour disease, we propose for it the term "multiple neuroendocrine carcinoma syndrome".