Intraepidermal and dermal Merkel cell carcinoma with squamous cell carcinoma in situ: a case report with review of literature

Abstract

Merkel cell carcinoma (MCC), a rare aggressive primary cutaneous neuroendocrine carcinoma, occurs on sun-damaged skin, especially in the elderly. Its unique co-expression of cytokeratin 20 (CK20) and neuroendocrine markers, including neuron-specific enolase (NSE), is diagnostic. Most MCCs are located in the dermis, rarely has an intraepidermal component been reported. We report a case of MCC with an intraepidermal component admixed with squamous cell carcinoma in situ (SCCIS). We were able to identify the differences in the immunohistochemical expression pattern between that of the intraepidermal and the dermal components. Most intraepidermal neoplastic cells of MCC in this case showed a less intense immunoreactivity to CK20 and NSE compared to that of dermal neoplastic cells. This case reports an unusual occurrence of combined SCC and MCC that shows both intraepidermal and dermal components.

Merkel Cell Carcinoma Concurrent with Bowen's Disease

“…It has been reported that some cases of MCC are concurrent with Bowen disease occurring in the same region synchronously2,5-9. Several studies suggested that arsenic is a carcinogen that may induce the occurrence of MCC in addition to squamous cell carcinoma, basal cell carcinoma, and Bowen disease7,8,12.…”

“…Histopathologically, the epidermis is involved in less than 10% of all MCC cases, and the tumor cells are located in the dermis and grow toward subcutaneous tissue, with a tendency to infiltrate vascular and lymphatic vessels1,2. The tumor cells are uniformly sized basophilic cells, with round or oval nuclei and small nucleoli.…”

“…MCC is usually found as a solitary lesion but is occasionally found to coexist with other diseases, such as squamous cell carcinoma, basal cell carcinoma, actinic keratosis, miscellaneous adnexal tumors, and rarely Bowen disease (Table 1)1,2,5-9. Two theories are postulated to explain these observations.…”

“…It usually arises in the head and neck of elderly people and tends to be more common in men1. Although it is usually found as a solitary lesion, it is occasionally found to coexist with other malignancies, such as squamous cell carcinoma, basal cell carcinoma, and rarely Bowen disease2. Herein, we report an interesting case of MCC concurrent with Bowen disease.…”

Primary squamous neuroendocrine carcinoma of the skin: A case report with immunohistochemical study

“…It mimicked an eccrine carcinoma. Sirikanjanapong et al [26] reported a case of intraepidermal and dermal MCC with squamous cell carcinoma in situ. Hwang et al [27] reported a case of MCC with squamous and sarcomatous differentiations.…”