Merkel cell carcinoma presenting as right leg edema in a multiple myeloma patient
Authors: Claire M. Noell, Elizabeth Rose, Lee T. Nesbitt
Journal: Journal of the American Academy of Dermatology (2014)

To the Editor: A 61-year-old man with intractable vomiting, fatigue, and acute renal failure was accurately diagnosed with stage III multiple myeloma as the initial neoplasm. He was treated with lenalidomide, dexamethasone, and bortezomib with an excellent response. Four months after treatment completion, he presented with persistent right lower extremity edema and pain. Deep vein thrombosis and renal artery stenosis were excluded with Doppler ultrasound. Physical examination revealed pitting edema to the knee with dusky erythema and scaling; laboratory investigations were significant for kidney failure. A computed tomography (CT) scan of the abdomen and pelvis revealed a 14- × 7-cm retroperitoneal nodal mass obstructing the ureters and bilateral hydronephrosis. A CT-guided biopsy revealed Merkel cell carcinoma (MCC) (Fig 1). No cutaneous lesions were evident at that time. The patient received external beam radiation therapy for the mass, which alleviated the edema and pain. Shortly thereafter he returned with painful, firm, erythematous nodules on his distal right leg, which demonstrated metastatic MCC on needle biopsy. He began a palliative regimen of carboplatin and etoposide, which resulted in pancytopenia and sepsis. The lesions recurred throughout his leg, thigh, and foot 1 month later with ulceration and bleeding (Fig 2). He subsequently began gemcitabine, which resulted in anemia requiring transfusions and metastatic progression. Chemotherapy was changed to temozolomide. Six months later, widely disseminated cutaneous lesions involved the left lower extremity, abdomen, and chest. Chemotherapy was discontinued in favor of palliative measures, and the patient died of disease progression 3 months later. MCC is a rare, highly aggressive neuroendocrine malignancy with a high rate of local recurrence and metastasis, and the diagnosis carries a poor prognosis. Increasing evidence has demonstrated a relationship between MCC and impaired immunity, whether iatrogenic after organ transplantation, acquired due to human immunodeficiency virus, or intrinsic due to malignancy.1Buell J.F. Trofe J. Hanaway M.J. Beebe T.M. Gross T.G. Alloway R.R. et al.Immunosuppression and Merkel cell cancer.Transplant Proc. 2002; 34: 1780-1781Abstract Full Text Full Text PDF PubMed Scopus (118) Google Scholar This association led to the discovery of the Merkel cell polyomavirus and its detection in the majority of MCC tumors, revealing an increased frequency of virus reactivation in immunocompromised patients.2Kassem A. Technau K. Kurz A.K. Pantulu D. Löning M. Kayser G. et al.Merkel cell polyomavirus sequences are frequently detected in nonmelanoma skin cancer of immunosuppressed patients.Int J Cancer. 2009; 125: 356-361Crossref PubMed Scopus (121) Google Scholar Recent case reports have suggested that primary cancers, especially chronic lymphocytic leukemia, non-Hodgkin lymphoma, and multiple myeloma, may predispose patients to development of MCC. Howard et al3Howard R.A. Dores G.M. Curtis R.E. Anderson W.F. Travis L.B. Merkel cell carcinoma and multiple primary cancers.Cancer Epidemiol Biomarkers Prev. 2006; 15: 1545-1549Crossref PubMed Scopus (136) Google Scholar demonstrated a greater than 3-fold increased risk of primary MCC development after multiple myeloma diagnosis with a median latency of 3.4 years. This case of MCC presenting with acute renal failure and impaired lower extremity venous drainage causing edema illustrates that the diagnosis of MCC may have been confounded by the patient's preexisting malignancy and residual kidney impairment due to light chain deposition. We also believe that persistent lymphedema of the right leg, which was likely the primary site of disease, masked the detection of this second primary malignancy. When treating immunocompromised patients, especially those with lymphohematopoietic malignancies, vigilance for the development of MCC should be considered, in that early detection can greatly impact prognosis and survival. This case reemphasizes that cutaneous malignancy risk assessment should be performed in the initial stages of management for every immunocompromised patient.