Merkel cell carcinoma

Abstract

Merkel cell carcinoma (MCC) is a rare, clinically aggressive cutaneous neuroendocrine neoplasm with a high mortality rate. Though the etiology is not precisely known, Merkel cell polyomavirus DNA has been found recently in a large percentage of MCC tumors. Other suggested risk factors include sun exposure, immunosuppression, and a history of prior malignancy. Work up of patients with MCC most notably includes nodal staging via clinical examination or sentinel lymph node biopsy. The prognosis for most patients with MCC is poor, and the rarity of MCC precludes the prospective, randomized clinical trials necessary to elucidate optimum treatment protocols. Most published data support the use of a multimodality approach centered around surgical excision with negative margins, sentinel lymph node biopsy to establish the presence or absence of nodal metastases, adjuvant radiothearpy to decrease the risk of recurrence, and systemic chemotherapy in the case of widespread disease.

Figure 1

Figures 1A–E illustrate clinical appearance of MCC. A. Rapidly growing violaceous firm painless nodule in the right ear. B. A large ulcerative lesion in the lower lip with clinical positive neck nodes. (Reprint request is pending) C. Multiple erythematous cutaneous nodules with central ulceration in buttock. (Reprint request is pending) D. Biopsy-proven MCC in the right lateral foot in proximity to previous squamous cell carcinoma. E. Metastatic MCC in the left breast.

Figure 1

Figures 1A–E illustrate clinical appearance of MCC. A. Rapidly growing violaceous firm painless nodule in the right ear. B. A large ulcerative lesion in the lower lip with clinical positive neck nodes. (Reprint request is pending) C. Multiple erythematous cutaneous nodules with central ulceration in buttock. (Reprint request is pending) D. Biopsy-proven MCC in the right lateral foot in proximity to previous squamous cell carcinoma. E. Metastatic MCC in the left breast.

Figure 1

Figures 1A–E illustrate clinical appearance of MCC. A. Rapidly growing violaceous firm painless nodule in the right ear. B. A large ulcerative lesion in the lower lip with clinical positive neck nodes. (Reprint request is pending) C. Multiple erythematous cutaneous nodules with central ulceration in buttock. (Reprint request is pending) D. Biopsy-proven MCC in the right lateral foot in proximity to previous squamous cell carcinoma. E. Metastatic MCC in the left breast.

Figure 1

Figures 1A–E illustrate clinical appearance of MCC. A. Rapidly growing violaceous firm painless nodule in the right ear. B. A large ulcerative lesion in the lower lip with clinical positive neck nodes. (Reprint request is pending) C. Multiple erythematous cutaneous nodules with central ulceration in buttock. (Reprint request is pending) D. Biopsy-proven MCC in the right lateral foot in proximity to previous squamous cell carcinoma. E. Metastatic MCC in the left breast.

Figure 1

Figures 1A–E illustrate clinical appearance of MCC. A. Rapidly growing violaceous firm painless nodule in the right ear. B. A large ulcerative lesion in the lower lip with clinical positive neck nodes. (Reprint request is pending) C. Multiple erythematous cutaneous nodules with central ulceration in buttock. (Reprint request is pending) D. Biopsy-proven MCC in the right lateral foot in proximity to previous squamous cell carcinoma. E. Metastatic MCC in the left breast.

Figure 2

Figures 2A–B. MCC histology demonstrating cords, trabeculae, or sheets of small monomorphic cell proliferation, with hyperchromatic nuclei and scanty cytoplasm, frequent mitoses and apoptotic bodies. Vascular invasion (arrow) is seen on 2B. Figures 2C–D. Immunostains illustrating uptake of CK20 (punctuated paranuclear stain) and NSE (in cytoplasm with a dark rim around the large round nucleus) immunostain. A. H&E stain, 100X. B. H&E stain, 400X C. CK20 stain, 400X (Reprint request is pending) D. NSE stain, 400X

Figure 2

Figures 2A–B. MCC histology demonstrating cords, trabeculae, or sheets of small monomorphic cell proliferation, with hyperchromatic nuclei and scanty cytoplasm, frequent mitoses and apoptotic bodies. Vascular invasion (arrow) is seen on 2B. Figures 2C–D. Immunostains illustrating uptake of CK20 (punctuated paranuclear stain) and NSE (in cytoplasm with a dark rim around the large round nucleus) immunostain. A. H&E stain, 100X. B. H&E stain, 400X C. CK20 stain, 400X (Reprint request is pending) D. NSE stain, 400X

Figure 2

Figures 2A–B. MCC histology demonstrating cords, trabeculae, or sheets of small monomorphic cell proliferation, with hyperchromatic nuclei and scanty cytoplasm, frequent mitoses and apoptotic bodies. Vascular invasion (arrow) is seen on 2B. Figures 2C–D. Immunostains illustrating uptake of CK20 (punctuated paranuclear stain) and NSE (in cytoplasm with a dark rim around the large round nucleus) immunostain. A. H&E stain, 100X. B. H&E stain, 400X C. CK20 stain, 400X (Reprint request is pending) D. NSE stain, 400X

Figure 2

Figures 2A–B. MCC histology demonstrating cords, trabeculae, or sheets of small monomorphic cell proliferation, with hyperchromatic nuclei and scanty cytoplasm, frequent mitoses and apoptotic bodies. Vascular invasion (arrow) is seen on 2B. Figures 2C–D. Immunostains illustrating uptake of CK20 (punctuated paranuclear stain) and NSE (in cytoplasm with a dark rim around the large round nucleus) immunostain. A. H&E stain, 100X. B. H&E stain, 400X C. CK20 stain, 400X (Reprint request is pending) D. NSE stain, 400X

Figure 3

Figures 3A–D. MCC Imaging. A. Abdominal CT illustrates metastatic retroperitoneal MCC. B. MRI shows recurrent MCC in distal right arm C. FDG-PET scan demonstrates metastatic MCC in the mediastinum and liver from a mandibular primary. (Reprint request is pending) D. PET-CT demonstrates metastatic biopsy-proven MCC in the right iliac node from a small foot primary.

Figure 3

Figures 3A–D. MCC Imaging. A. Abdominal CT illustrates metastatic retroperitoneal MCC. B. MRI shows recurrent MCC in distal right arm C. FDG-PET scan demonstrates metastatic MCC in the mediastinum and liver from a mandibular primary. (Reprint request is pending) D. PET-CT demonstrates metastatic biopsy-proven MCC in the right iliac node from a small foot primary.

Figure 3

Figures 3A–D. MCC Imaging. A. Abdominal CT illustrates metastatic retroperitoneal MCC. B. MRI shows recurrent MCC in distal right arm C. FDG-PET scan demonstrates metastatic MCC in the mediastinum and liver from a mandibular primary. (Reprint request is pending) D. PET-CT demonstrates metastatic biopsy-proven MCC in the right iliac node from a small foot primary.

Figure 3

Figures 3A–D. MCC Imaging. A. Abdominal CT illustrates metastatic retroperitoneal MCC. B. MRI shows recurrent MCC in distal right arm C. FDG-PET scan demonstrates metastatic MCC in the mediastinum and liver from a mandibular primary. (Reprint request is pending) D. PET-CT demonstrates metastatic biopsy-proven MCC in the right iliac node from a small foot primary.