Abstract
Merkel cell carcinoma (MCC) is a relatively rare but aggressive primary neuroendocrine carcinoma of the skin. MCC frequently occurs on sun-exposed areas in elderly Caucasian patients and has a propensity for local recurrence, regional lymph node invasion and distant metastases. However, MCC occurring on sites that are not sun-exposed in Asian patients is extremely uncommon. The current study describes the case of a 66-year-old Chinese male who presented with an asymptomatic, smooth lesion in the left inguinal region, which was initially diagnosed as a malignant lymphoma. Upon histological and immunohistochemical analysis, the tumor was consistent with the diagnosis of an MCC. In conclusion, due to its low incidence rate and lack of characteristic clinical manifestations, the final diagnosis of MCC relies on the analysis of histological findings and immunohistochemical markers following lesion biopsy or resection. The present study aimed to report a case of MCC and present a brief literature review in order to bring attention to the diagnosis of this condition.
Highlights
Introduction characteristicsHistologically, Merkel cell carcinoma (MCC) exhibits sheets of monomorphous small blue cells, which may be confused with other closely associated skin neoplasms, such as small cell lung cancer (SCLC), cutaneous lymphoma, melanoma, Ewing's sarcoma and rare basal cell carcinoma [3]
The present study reports the case of a Chinese male who presented with an unusual nodule in the left groin, without sun exposure, which was initially diagnosed as a malignant lymphoma, but was later proven to be an MCC following immunohistochemical studies
The results demonstrated that the tumor cells were strongly positive for neuroendocrine markers, including chromogranin A (CgA) and synaptophysin (Syn), and epithelial markers cytokeratin (CK) 20, CK8/18 and epithelial membrane antigen (EMA) (Fig. 1D‐H), but negative for leukocyte common antigens (LCA), thyroid transcription factor‐1 (TTF‐1), Melan‐A, human melanoma black 45 (HMB45), vimentin (Vim), S‐100, cluster of differentiation (CD)34, CD57 and CD99
Summary
A 66‐year‐old Chinese male presented to the Deaprtment of Pathology, The Third Affiliated Hospital of Soochow University (Changzhou, China) in May 2009 with complaints of a 2‐cm asymptomatic, smooth and firm nodule in the left inguinal region. The results demonstrated that the tumor cells were strongly positive for neuroendocrine markers, including chromogranin A (CgA) and synaptophysin (Syn), and epithelial markers cytokeratin (CK) 20, CK8/18 and epithelial membrane antigen (EMA) (Fig. 1D‐H), but negative for leukocyte common antigens (LCA), thyroid transcription factor‐1 (TTF‐1), Melan‐A, human melanoma black 45 (HMB45), vimentin (Vim), S‐100, cluster of differentiation (CD), CD57 and CD99. These histopathological and immunohistochemical features were consistent with a diagnosis of MCC. A corrected diagnosis of MCC was made for this patient
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