Merkel cell carcinoma metastatic to the testis: report of a rare diagnosis and review of the literature

Merkel cell carcinoma is an aggressive malignancy that frequently recurs/disseminates, but metastases to the genitourinary tract are rare. Only eight cases of Merkel cell carcinoma metastatic to the testis are reported. We describe the ninth case of this event and provide a review of the literature. A 58-year-old man diagnosed with Merkel cell carcinoma of the wrist, presented, 37 months later, a recurrence in the form of a testicular metastasis. The tumor consisted of a monotonous proliferation of small, blue, round cells, with immunoexpression of neuroendocrine markers and the typical dot-like paranuclear immunostaining for cytokeratin 20, in the absence of immunostaining for cytokeratin 7. The patient is alive with no evidence of disease. Clinicians should be aware of the possibility of metastatic dissemination to the testis since genital examination/imaging is not part of routine follow-up for these patients, but timely orchiectomy may be curative.

Metástasis selar y al seno cavernoso, de un carcinoma de células de Merkel: reporte de un caso / Sellar and cavernous sinus metastasis from a Merkel cell carcinoma: case report and literature review

El carcinoma de células de Merkel es un tumor maligno y muy raro de la piel. Este tumor emerge de las células epiteliales que presentan una diferenciación neuroendocrina. Ocurre más comúnmente en los adultos masculinos mayores. Las metástasis intracraneales de un carcinoma de células de Merkel son aun más raras. En este articulo, se presentara un caso de un paciente masculino de 70 años con antecedente de carcinoma de células de Merkel quien debuto con una ptosis que progresivamente presento una parálisis completa del tercer par craneal. En los estudios realizados al paciente, se encontró una lesión infiltrante al seno cavernoso y a la silla turca que resulto ser una metástasis por un carcinoma de células de Merkel. En esta publicación, se discutirá el caso clínico y se revisará la literatura al respecto de estas lesiones raras del sistema nervioso central.

Merkel cell carcinoma is a rare and malignant tumor of the skin. This lesion arises from epithelial cells that have undergone neuroendocrine differentiation. They are more commonly found in older male adults. Intracranial metastases from Markel cell carcinoma are even rarer. We will present a case of a 70 year old male with known history of Merkel cell carcinoma that suddenly presented with a right eye ptosis and progressively presented complete third nerve palsy. The patient was studied and was found to have an infiltrating lesion of the cavernous sinus and the sellar region. This tumor resulted in a metastasis from a Merkel Cell Carcinoma. In this article we will discuss the clinical case of this patient and we will review the literature concerning this rare lesion of the Central nervous system.