Cutaneous neuroendocrine carcinoma (Merkel cell carcinoma) arising in association with basal cell carcinoma and squamous cell carcinoma in-situ of skin with metastasis to supraclavicular lymph nodes involved by chronic lymphocytic leukemia/small lymphocytic lymphoma.
Primary cutaneous neuroendocrine carcinoma, commonly referred to as Merkel cell carcinoma (MCC), is a high grade malignancy of skin having a primitive neural phenotype. The most common sites of occurrence are on the distal extremities and, as seen in our patient, the head/neck region. When occurring in isolation it has been clinically described as nodular and having a violaceous hue.
MCC commonly has regional lymph node metastasis and not uncommonly has distant metastasis as well (lungs, liver, bones). Therefore, treatment is aggressive with wide excision followed by regional lymph node dissection and judicious use of radiation therapy as an adjunct (1).
Though most cases of MCC occur in isolation, many cases have been described arising in association with other cutaneous neoplasms the most frequent of these being squamous cell carcinoma. Some authors postulate that up to 25% of patients with MCC show squamous carcinoma (either Bowen's disease or invasive) in the same cutaneous region (2). Other tumors that have been observed in less frequent association with MCC include appendageal tumors with pilar differentiation (3), benign adnexal adenoma (4), epidermal cyst (5), sweat gland carcinoma (2), congenital nevus (6), and melanoma (2). There are also two reports of occurrence of MCC in young patients with ectodermal dysplasia (7,8). Finally, a case remarkably similar to ours has been reported where MCC, squamous cell carcinoma, and basal cell carcinoma were seen arising in the same cutaneous site (9).
Chronic lymphocytic leukemia/small cell lymphoma (CLL), a CD5+ small B-cell lymphoproliferative disorder, is well documented to exist synchronously with other somatic neoplasms especially skin cancers; a recent global survey was published by Agnew et al.(10). In the literature there are at least eight separate reports of CLL co-exisiting with MCC making the association rare but well recognized (11-13).
The well documented phenomenon of these neoplasms to arise synchronously, particularly MCC with squamous and basal carcinoma of skin, MCC with CLL, and CLL with squamous carcinoma, perhaps from a conceptual point of view does not make the case presented here so unusual. However, to our knowledge, we report the first case of MCC arising in association with cutaneous squamous and basal cell carcinoma in a patient with CLL where the MCC component subsequently metastasized to regional lymph nodes involved by CLL.
Contributed by Sourav Ray MD, Drazen M Jukic MD PhD, Juan Rosai MD