A Red Nodule on the Cheek - a Case Report

Introduction: Merkel cell carcinoma (MCC) is a rare, very aggressive neuroectodermal tumor of the skin typically located on sun-exposed areas and frequently found in Caucasian men between 70 and 80 years of age.

Case Report: We present a case of a 86-year-old woman who was referred to our Skin Cancer Unit with a red and well defined nodule located on her left commissure of the mouth, that grew during a couple of months and was completely asymptomatic. Dermoscopic examination revealed a reddish background with linear and arborizing irregular vessels, some out of focus vessels and whitish areas. The lesion was excised, histological examination showed that the tumor was hypercellular and composed of round epithelial elements with large nuclei and scant cytoplasm suggestive of MCC. Immunohistochemical stains confirmed a diffuse positivity with cytokeratin (CK) 2 chromogranin, and synaptophysin; CK7 and thyroid transcription factor-1(TTF-1) were negative. Sentinel lymph node biopsy was done, resulting negative for neoplastic cells, and computed tomography (CT) of the chest, abdomen and pelvis showed no distant metastasis. Adjuvant radiotherapy on the tumor site and on homolateral neck lymph nodes was also done.

Conclusion: Merkel cell carcinoma presents as an asymptomatic, rapidly growing nonpigmented nodule without specific characteristics. Dermoscopic features may help to distinguish MCC from other similar tumors: linear irregular vessels, milky pink areas, architectural disorders and structureless areas, even if not specific, when present are strongly suggestive of MCC. Wide excision with 2 cm margins with adjuvant radiotherapy is the treatment of choice in high-risk primary tumors, while sentinel lymph node biopsy and computed tomography scans are necessary for early diagnosis of metastatic disease.