Metastatic Merkel cell carcinoma: a case of spontaneous regression


Victoria Guiote1, Fernanda Cunha1, André Pinho2, Ana Brinca2, Ricardo Vieira2

1 Centro Hospitalar Leiria-Pombal, Portugal.

2 Centro Hospitalar e Universitário de Coimbra, Portugal.

Case presentation:

A 89-year-old woman, skin type III, farmer during 40 years and with no relevant past medical history was observed with an asymptomatic, purple, dome-shaped tumor with transmural invasion of the left nasal ala (fig. 1). An enlarged, firm and adherent lymph node with 3 cm was palpable in the left submandibular region.

fig. 1

 Work up:

The biopsy of the tumor revealed a dermal infiltrate composed by small round cells with scanty cytoplasm and nucleus with powdery chromatin and inconspicuous nucleoli (fig. 2a). The tumor cells were organized in strands and were positive for neuroendocrine markers (synaptophysin and chromogranin A) and epithelial markers, namely cytokeratin 20 in a paranuclear dot-like pattern (fig. 2b, 2c and 2d), typical of Merkel  cell carcinoma. Detection of DNA of Merkel cell polyomavirus in paraffin-embedded lesional skin was negative under quantitative real-time polymerase chain reaction analysis.

fig. 2a, 2b, 2c & 2d

Fine needle aspiration disclosed a lymph node metastasis in the left submandibular region. A positron-emission tomography/computed tomography with (68)Ga-DOTATOC detected a single liver metastasis with 2 cm in diameter localized in the segment IV. The patient was staged in the stage IV (T4 N1b M1c) of the American Joint Committee on Cancer 7th edition.

The performance status of the patient wase ECOG 3.

Treatment and outcome:

Due to the poor performance status of the patient, palliative radiation therapy applied to the primary tumour and to the regional metastases was proposed. However, a complete spontaneous clinical remission was achieved 6 weeks after the biopsy (fig.3) and radiation therapy was not performed. A cervical and hepatic ultrasonography also revealed the concomitant disappearance of both lymphatic and hepatic metastasis. The patient remains disease-free after a 9-month follow-up.

fig. 3

Key message:

Merkel cell carcinoma is an aggressive skin malignancy with a relatively high recurrence rate and propensity for metastatic spread. The spontaneous regression is a very rare occurrence in Merkel cell carcinoma with very few cases reported so far1-5, generally occurring after the biopsy of the primary tumour2,3. The underlying mechanism for this occurrence is unclear but there is scarce evidence suggesting a relevant role of T-cell mediated immune response2,3. Further investigation is required to confirm whether the presence of the virus has any influence in the likelihood of complete spontaneous remission, as mentioned by some authors2,3. It is remarkable that the complete spontaneous regression of this aggressive skin neoplasm is usually definitive, with no recurrences reported (the patients who did not survived during the follow-up died of other causes not related with Merkel cell carcinoma)3,5.


  1. Sugamata A, Goya K, Yoshizama N. A case of complete spontaneous regression of extremely advanced Merkel cell carcinoma. JSCR (Journal of Surgical Case Reports) 2011.10:7
  2. Richetta AG, Mancini M, Torroni A, et al. Total spontaneous regression of advanced Merkel cell carcinoma after biopsy: review and a new case. DermatolSurg. 2008.34:815-822
  3. Moghaddam PA, Cornejo KM, Tomaszewicz K, et al.  Complete spontaneous regression of Merkel cell carcinoma after biopsy: a case report and review of the literature. Am J Dermatopathol 2016;38:e154-e158
  4. Shito H, Kukko H, Koljonen V, et al. Clinical factors associated with Merkel  cell polyomavirus infection in Merkel cell carcinoma. J Natl Cancer Inst.2009.101:938-945
  5. Cirillo F. Spontaneous regression of primitive Merkel cell carcinoma. Rare Tumors 2015;7:5961