Metastatic merkel cell tumor to bladder presenting as an encroachment tumor with gross hematuria

Metastatic Merkel cell tumor to the prostate and bladder

Merkel cell carcinoma is an uncommon cutaneous neoplasm of neuroendocrine origin. We report the case of a 71-year-old man with Merkel cell carcinoma metastases to the prostate and bladder presenting with lower urinary tract obstruction. Efforts should be made to optimize the patient's quality of life with the finding of metastatic Merkel cell carcinoma to the bladder or prostate until better adjuvant therapies are identified.

Metastatic Merkel cell carcinoma to the soft tissues of the lower back

Merkel cell carcinoma (MCC) is a rare primary cutaneous neuroendocrine carcinoma. It has a propensity for both locoregional and distant recurrence despite treatment. We describe the case of a 51-year-old man diagnosed with MCC of the left forehead. At 14 months post surgery and adjuvant radiotherapy he developed an isolated deposit of metastatic MCC in the paraspinal soft tissues of his lower back. This atypical site of metastatic disease was treated with radiotherapy and combination chemotherapy. Atypical and isolated sites of metastatic MCC, although infrequently reported, highlight the often bizarre nature of this aggressive skin cancer. Treatment in such cases needs to be individualized.

Imaging of Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a rare, highly malignant cutaneous tumor, primarily of the head and neck, that requires timely diagnosis, adequate staging, and aggressive therapy. MCC tends to be overlooked in the early stage, has a high propensity for invading local and regional nodal basins, and exhibits a high postoperative recurrence rate, with distant thoracic, abdominal, and central nervous system metastases. Conventional radiography and cross-sectional imaging show lesions similar to those originating from other small cell carcinomas. Nuclear medicine procedures such as sentinel node scintigraphy, somatostatin receptor scintigraphy, and positron emission tomography may be used to supplement judicious cross-sectional imaging evaluation, thereby adding diagnostic value in staging and providing therapeutic guidance. Ultimately, however, the diagnosis relies exclusively on pathologic findings at immunohistochemical staining and electron microscopy. The rarity of MCC and the resulting insufficient awareness of this neoplasm often delay correct identification and treatment, which essentially consists of wide-margin surgical excision of the primary tumor and local and regional radiation therapy. To date, clinical information is still insufficient to fully appreciate the role of imaging in MCC management. A better imaging algorithm is expected with increased awareness and improved clinical understanding of this uncommon skin neoplasm.