Merkel细胞癌多瘤病毒阳性的皮肤原发性Merkel细胞癌二例

【摘要】 目的 报道Merkel细胞癌多瘤病毒阳性的Merkel细胞癌2例。 方法 对诊治的2例Merkel细胞癌进行光镜观察及免疫组化标记,聚合酶链反应（PCR）检测Merkel细胞癌多瘤病毒并测序。 结果 2例均为男性,例1右下肢胫前肿物1年余,皮肤科检查见右胫前密集粉红色结节,融合成10 cm × 8 cm肿块,质硬,部分表面糜烂伴渗出及结痂,肿块周围亦可见多个大小不一的红色结节,活动性差。例2左膝肿物6月余,皮肤科检查见左膝内侧5 cm × 4 cm紫蓝色结节型肿物,质硬,边界不清,活动性差。2例患者皮损组织病理表现相似,肿瘤细胞大小一致,细胞核大、深染,染色质细腻,核分裂象易见;胞质少,红染。免疫组化：广谱细胞角蛋白（pan-CK）、细胞角蛋白20（CK20）、突触素（Syn）、嗜铬素（CgA）和神经元特异性烯醇化酶（NSE）均阳性,Ki-67（≥60%）阳性;细胞角蛋白7（CK7）、S100蛋白、HMB45、CD34、甲状腺转录因子1（TTF-1）和白细胞共同抗原（LCA）表达均阴性。2例Merkel细胞癌均经PCR检测到Merkel细胞癌多瘤病毒,而5例皮肤T细胞淋巴瘤、2例正常人皮肤和2例T细胞淋巴瘤细胞系MAC1和MAC2A均未检测到Merkel细胞癌多瘤病毒。 结论 Merkel细胞癌具有特征性的临床和组织病理表现,免疫组化标记、PCR检测Merkel细胞癌多瘤病毒对明确诊断具有重要作用。 【关键词】 癌,Merkel细胞; 多瘤病毒属     

Metastatic Merkel cell carcinoma with an unknown primary tumour presenting as lichenoid dermatitis

Metastatic Merkel cell carcinoma uncommonly presents with an unidentified primary tumour. We report a patient who first presented with lichenoid dermatitis and was found to have Merkel cell carcinoma involving lymph nodes with an unknown primary site. With the rising incidence of Merkel cell carcinoma, it is important to recognize unusual manifestations of this disease as they may become more common in the future.     

Merkel cell polyomavirus DNA detection in lesional and nonlesional skin from patients with Merkel cell carcinoma or other skin diseases

Summary Background A novel polyomavirus, the Merkel cell polyomavirus (MCPyV), has recently been identified in Merkel cell carcinoma (MCC). Objectives To investigate the specificity of this association through the detection, quantification and analysis of MCPyV DNA in lesional and nonlesional skin biopsies from patients with MCC or with other cutaneous diseases, as well as in normal skin from clinically healthy individuals. Methods DNA was extracted from lesional and nonlesional skin samples of patients with MCC or with other cutaneous diseases and from normal‐appearing skin of clinically healthy subjects. MCPyV DNA was detected by polymerase chain reaction (PCR) and quantified by real‐time PCR. Additionally, the T antigen coding region was sequenced in eight samples from seven patients. Results MCPyV DNA was detected in 14 of 18 (78%) patients with MCC, five of 18 (28%) patients with other skin diseases (P = 0·007) and one of six (17%) clinically healthy subjects. In patients with MCC, viral DNA was detected in nine of 11 (82%) tumours and in 10 of 14 (71%) nontumoral skin samples (P = 0·66). MCPyV DNA levels were higher in MCC tumours than in nontumoral skin from patients with MCC, and than in lesional or nonlesional skin from patients with other cutaneous disorders. Signature mutations in the T antigen gene were not identified in the two MCC tumour specimens analysed. Conclusions High prevalence and higher levels of MCPyV DNA in MCC supports a role for MCPyV in tumorigenesis. However, the high prevalence of MCPyV in the nontumoral skin and in subjects without MCC suggests that MCPyV is a ubiquitous virus.     

Patched 1 expression in Merkel cell carcinoma

The relevance of Hedgehog signaling in Merkel cell carcinoma has only been addressed by a few studies with conflicting results. Thus, we aimed to establish the expression of Hedgehog signaling molecules in Merkel cell carcinoma to characterize causes of aberrant expression and to correlate these findings with the clinical course of the patients. Immunohistochemistry was performed for Sonic, Indian, Patched 1 (PTCH1) and Smoothened on patients’ tumor tissue. Respective mRNA expression was analyzed in 10 Merkel cell carcinoma cell lines using quantitative real‐time polymerase chain reaction. PTCH1 sequencing and DNA methylation microarray analyses were carried out on tumor tissues as well as cell lines. PTCH1 immunoreactivity in Merkel cell carcinoma was similar to that of basal cell carcinomas, which both significantly differed from PTCH1 immunoreactivity in healthy skin. Most PTCH1 mutations found were synonymous or without known functional impact. However, on average, the promoter regions of both PTCH1 were hypomethylated independently from PTCH1 gene expression or Merkel cell polyomavirus status. PTCH1 and GLI1/2/3 genes were differently expressed in different cell lines; notably, there was a significant correlation between GLI2 and PTCH1 mRNA expression. Similar to PTCH1 protein expression in patient tissues, PTCH1 gene expression in Merkel cell carcinoma cell lines is highly variable, but due to the similar methylation pattern across Merkel cell carcinoma cell lines, effects other than methylation seem to be the reason for the differential expression and PTCH1 appears to be upregulated by GLI as a classical Hedgehog target gene.     

Merkel cell carcinoma with heterologous rhabdomyoblastic differentiation: the role of immunohistochemistry for Merkel cell polyomavirus large T-antigen in confirmation

Merkel cell carcinoma (MCC) represents an uncommon and lethal form of cutaneous malignancy. Historically, the pathogenesis of MCC has been presumed to be linked to ultraviolet light overexposure, but recently, it has been documented that some examples harbor polyomavirus genome, the presence of which is presumed to be of pathogenetic importance. Extremely rare cases of MCC may show heterologous differentiation. We report an example of MCC with heterologous rhabdomyosarcomatous differentiation, the third such case to date, with emphasis on its distinction from fusion-negative alveolar rhabdomyosarcoma. The role of immunohistochemistry for Merkel cell polyomavirus large T-antigen in this differential diagnosis is emphasized.     

Merkel cell carcinoma in situ: New insights into the cells of origin

We report a case of a 71-year-old male who presented with a small skin-coloured plaque on his cheek. Histopathology demonstrated an intraepidermal carcinoma with follicular involvement. No evidence of dermal invasion was seen. Immunohistochemical studies showed areas of positive staining for CK20, EMA and synaptophysin. Histopathology findings were found to be most consistent with a diagnosis of intraepidermal carcinoma with features of Merkel cell carcinoma in situ, in combination with a squamous cell carcinoma in situ, with follicular involvement. Recent advances and findings suggest Merkel cell polyomavirus MCPyV-positive Merkel cell carcinoma and MCPyV-negative Merkel cell carcinoma have different cells of origin from different germ layers.     

Merkel cell carcinoma

ABSTRACT: Merkel cell carcinoma is a rare cutaneous malignancy that occurs mainly in the ultraviolet‐exposed areas of the head and neck region and has a mortality rate higher than that of melanoma (33%) with a tendency to recur. The clinical features, diagnosis, work up, and current recommendations for treatment of Merkel cell carcinoma are discussed.     

Usefulness of ulceration and hyperkeratosis as clinical predictors of Merkel cell polyomavirus‐negative and combined Merkel cell carcinoma: A retrospective study

Merkel cell carcinoma is a rare neuroendocrine carcinoma of the skin that is associated with Merkel cell polyomavirus (MCPyV). The clinical appearance and demographic characteristics of this tumor have been described using the mnemonic AEIOU: asymptomatic, expanding rapidly, immune suppression, older than 50 years, and ultraviolet‐exposed fair skin. In addition, MCC can be categorized based on morphology as pure MCC or combined MCC that exhibits neuroendocrine and other phenotypic elements. There is limited information regarding the clinical characteristics and prognosis of combined MCC. This retrospective study aimed to identify factors, such as ulceration or hyperkeratosis, that could predict MCPyV status and morphological variants. Twenty patients with MCC were divided into groups based on MCPyV status and morphology: MCPyV‐positive or MCPyV‐negative MCC and pure or combined MCC. The patients’ MCPyV status was immunohistochemically determined using the CM2B4 antibody to the MCPyV large T‐antigen. The patients’ clinicopathological characteristics were evaluated to identify predictors of MCPyV‐negative MCC and combined MCC. The presence of ulceration/hyperkeratosis predicted the presence of MCPyV‐negative MCC (80% of cases) and combined MCC (50% of cases). None of the 10 patients with MCPyV‐positive MCC had ulceration/hyperkeratosis. The clinical presence of ulceration/hyperkeratosis may help guide the diagnosis of MCPyV‐negative MCC and combined MCC.     

Therapy of metastasized Merkel cell carcinoma with liposomal doxorubicin in combination with radiotherapy

Background: Merkel cell carcinoma is a rare skin cancer of neuroendocrine origin, which is characterized by a high rate of recurrence, metastatic spread and mortality. Because of its rarity, evidence‐based therapeutic regimens are difficult to establish. Merkel cell carcinoma is known to be both radio‐ and chemosensitive. Toxicity is a key factor in assessing any regimen, as the patients are usually elderly and likely to have other significant medical problems. Patients and Methods: We retrospectively evaluated five patients with metastatic Merkel cell carcinoma to see if liposomal doxorubicin (Caelyx^® or Myocet^®) in combination with radiotherapy exhibited clinical anti‐tumoral effects accompanied by acceptable side effects. Results: The outpatient chemotherapy regimen was tolerated without major side effects and produced good response rates. All patients achieved at least tumor stabilization; four of five had a partial remission. Effects of therapy were usually seen in the first cycle of therapy but the responses were of short duration with an average interval of two months until progression. Conclusions: As combined radiochemotherapy with liposomal doxorubicin is well tolerated even in older patients with other illnesses and can be given on an outpatient basis, it is an attractive option for metastatic Merkel cell carcinoma. Based on response rate or overall survival, it offers no advantages compared to polychemotherapy.     

Postoperative hyponatremia in a patient with ACTH-producing Merkel cell carcinoma

Merkel cell carcinoma is characterized by specific neuroendocrine features and the expression of several neuropeptides. We report a case of Merkel cell carcinoma with post-surgical hyponatremia in an 85-year-old Japanese woman. A tumor on the left cheek histopathologically showed the characteristics of Merkel cell carcinoma together with Bowen's disease. Although an increased level of ACTH was found both in the tumor and in the peripheral blood, the postoperative hyponatremia in our patient seems more likely to have been caused by the stress of the operation and indapamide, considering that the ACTH level in the tumor was much lower than those in other ectopic ACTH-producing tumors in previous reports.     

Triphasic differentiations of Merkel cell carcinoma in primary and metastatic lesions

We present a rare case of Merkel cell carcinoma (MCC) with heterologous differentiation. The patient was an 86‐year‐old female patient with MCC who presented with a forearm skin tumor and left axillary lymph node swelling. Histopathologically, the malignant components of the primary and metastatic lesions showed the intermingled features of triphasic phenotype differentiation, which had distinct cell populations; MCC, sweat gland carcinoma (SGC) and malignant poorly differentiated spindle cells with myogenic differentiation were immunohistochemically showed. Moreover, an electron microscopic observation of the tumor cells revealed intracytoplasmic canaliculi and junctional structures that indicated ductal differentiation. To our knowledge, this is the first case of MCC admixed with SGC and sarcomatous components in both the primary and metastatic lesions. An immunohistochemical study, using several stem cell markers, indicated that the MCC arose from pluripotent epidermal stem cells.     

Case of Merkel cell carcinoma with squamous cell carcinoma possibly arising in chronic radiodermatitis of the hand

We report a case of Merkel cell carcinoma (MCC) on the dorsal aspect of the right middle finger associated with multiple squamous cell carcinomas (SCC) possibly arising in chronic radiation dermatitis of the hand of an 80‐year‐old surgeon. In spite of resection of the primary lesion and right axillary lymph nodes, he died of the tumor 5 months after the first visit. Cutaneous and lymph node lesions of MCC were negative for Merkel cell polyoma virus (MCPyV) by immunostaining using monoclonal antibody (CM2B4) and anti‐large T antigen of MCPyV polyclonal antibody, and real‐time polymerase chain reaction. Several differences in clinicopathological findings have been found between MCPyV‐positive cases and negative ones. Several authors have reported that MCPyV‐negative cases have a worse prognosis than MCPyV‐positive ones. Furthermore, in cases of MCC associated with SCC, most tumors have been reported to be MCPyV‐negative. We should pay more attention to the relationship between the carcinogenesis of MCC and ionizing irradiation.     

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

Abstract The bcl-2 proto-oncogene, which is involved in the regulation of apoptosis, is expressed in a wide varity 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 immunofluorescencc 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 immunoreactivtiy 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.