Background:

Merkel cell carcinoma is a rare and often aggressive neuroendocrine cutaneous malignancy typically arising in older Caucasians. Immunosuppression, exposure to ultraviolet radiation and Merkel cell polyomavirus are implicated in its pathogenesis. In-transit metastases, secondary to dermal lymphatic vessel invasion, may occur in the subcutaneous tissues between the primary site and draining lymph nodes.

Methods:

We report an unusual case of a Merkel cell carcinoma, presenting initially on the hand of a 70 year old female with the rapid development of liver metastases and in-transit metastases that eventually involved the entire left upper limb. The patient had previously undergone left axillary dissection and irradiation for breast cancer.

Results:

Initial palliative chemotherapy with Carboplatin and Etoposide produced a minimal response from the in-transit metastases, but resolution of the liver metastases and she proceeded to a Docetaxel regime. Palliative whole limb radiotherapy was also ineffective. The in-transit metastases rapidly progressed and were refractory to treatment leading to a marked impact on her quality of life secondary to infection and bleeding. She ultimately proceeded to an uncomplicated palliative above elbow amputation with marked improvement in her well-being. Detailed photographic imaging of her clinical course will be provided.

Conclusion:

Merkel cell carcinoma can be rapidly progressive with a propensity for regional metastases via lymphatic vessels. We postulate that previous axillary treatment markedly disrupted the upper limb lymphatic vessel drainage and resulted in refractory and rapidly progressive in-transit metastases. In this case, we believe that palliative amputation of the involved arm was justified and beneficial to the patient.