A Merkel-cell carcinoma metastatic to the tonsil: a case report and review of the literature

A rare tonsillar metastasis of Merkel cell carcinoma: A case report

Merkel cell carcinoma (MCC) metastasis to the tonsil is extremely rare with five published cases. We report the case of a patient with palatine tonsillar MCC metastasis, who presented without oropharyngeal symptoms, which contrast prior reported cases.

Not Your Typical Tonsil: Metastatic Merkel Cell Carcinoma or Primary Disease?

Merkel cell carcinoma (MCC) is a rare, aggressive neuroendocrine tumor that almost always presents as a cutaneous lesion in the sun-exposed areas on the bodies of elderly white males. Metastasis to lymph nodes in the presence or absence of a known primary site and occurrence of these tumors in non-sun-exposed sites have also been described; however, an incidence of recurrent disease arising in the palatine tonsil in the absence of any detectable primary lesion has never been reported in the literature. In this report, we discuss a case of a 72-year-old female who was found to have a single axillary lymph node, which was resected and proved to be positive forMCC of unknown primary (MCCUP). Since there was no evidence of additional disease, the patient elected not to pursue adjuvant therapies. Six and a half months later, she presented with a complaint of dysphagia and a right-sided exophytic tonsillar mass. Tonsillectomy revealed MCC with no detectable primary cutaneous lesion. She received adjuvant therapy with avelumab and demonstrated a complete response after one year of bi-weekly treatments. Seven months following cessation of adjuvant treatments, surveillance positron emission tomography (PET) revealed enlarged retroperitoneal, pretracheal, periaortic, and left axillary lymph nodes concerning for recurrence. She elected to forgo additional biopsies and restarted avelumab the following month. She continues to be followed up on a monthly basis.

A unique case of merkel cell carcinoma with ovarian metastasis

BACKGROUND

Merkel cell carcinoma (MCC) is a rare cutaneous/mucosal malignancy with very aggressive biology and increasing incidence. Ovarian metastasis is an exceptionally rare site for MCC, and only two cases have been reported in the literature.

CASE REPORT

We report MCC with ovarian metastasis. A 34 year-old female with previously excised MCC from preauricular skin presented with a pelvic mass 15 months after first diagnosis. Anti-cytokeratin (CK) 20 positivity, LCA (leucocyte common antigen), and TTF-1 (Thyroid transcription factor-1) negativity confirmed metastatic ovarian MCC. There was no evidence of recurrence or metastasis at 12 months after salpingooopherectomy.

CONCLUSION

MCC should be considered in the differential diagnosis of primary and metastatic undifferentiated small round cell tumors of the ovary.

Merkel cell polyomavirus: molecular insights into the most recently discovered human tumour virus

A fifth of worldwide cancer cases have an infectious origin, with viral infection being the foremost. One such cancer is Merkel cell carcinoma (MCC), a rare but aggressive skin malignancy. In 2008, Merkel cell polyomavirus (MCPyV) was discovered as the causative agent of MCC. It is found clonally integrated into the majority of MCC tumours, which require MCPyV oncoproteins to survive. Since its discovery, research has begun to reveal the molecular virology of MCPyV, as well as how it induces tumourigenesis. It is thought to be a common skin commensal, found at low levels in healthy individuals. Upon loss of immunosurveillance, MCPyV reactivates, and a heavy viral load is associated with MCC pathogenesis. Although MCPyV is in many ways similar to classical oncogenic polyomaviruses, such as SV40, subtle differences are beginning to emerge. These unique features highlight the singular position MCPyV has as the only human oncogenic polyomavirus, and open up new avenues for therapies against MCC.