Spontaneous Regression in Merkel Cell Carcinoma

Abstract

The authors have indicated no significant interest with commercial supporters.M erkel cell carcinoma (MCC) is a malignant neuroendocrine tumor that typically affects elderly patients. 1 It is aggressive, with frequent recurrences after excision. Regional and distant metastases develop in approximately 40% of cases. Patients without lymph node involvement have been reported to have a survival rate of 75% at 5 years, whereas patients with distant metastases have a survival rate of 25% at 5 years. 2 The etiology of MCC remains unknown, although a polyomavirus has recently been linked to this tumor. 3 The incidence reported is higher in men than in women. 2,4 Surgery is the primary approach for clinically localized disease, although there is great variability regarding the use of further treatments. 5 Some studies have suggested that the use of sentinel lymph node biopsy improves survival and decreases nodal recurrence. 6 Recent studies have also demonstrated that the use of local adjuvant radiation after surgery lowers the risk of local and regional recurrences. 7,8 Despite the highly malignant course of this tumor, there have been reports of spontaneous regression. 9-27 We report two cases of MCC with complete spontaneous regression after skin biopsy and describe the clinical, histologic, and dermoscopic features. Case Report Patient 1A healthy 86-year-old woman presented with a nodular lesion on her right cheek that had appeared 5 weeks previously. Clinical examination revealed a pinkish-red, firm, non-ulcerated nodule measuring 22 Â 12 mm (Figure 1). Dermoscopy revealed a polymorphous vascular pattern over a cherry-colored homogeneous base. This pattern was composed of linear and comma vessels and vessels that were longer and more curved than comma vessels. We describe these as horseshoe-like structures (Figure 2). In addition, white streaks were present in the central part of the tumor.An incisional biopsy revealed a tumor in the deep dermis and a normal epidermis. The tumor cells were small and arranged in layers and solid networks ( Figure 3A and B). They had a uniform appearance, with round and hyperchromatic nuclei and scanty cytoplasm. Immunohistochemical staining was positive for neurone-specific enolase, chromogranin, synaptophysin, p-53, bcl-2, and cytokeratin 20 (CK20). Ki-67 expression was strongly positive (480%). Immunological studies showed a moderate infiltrate of CD3 1 cells around the tumor nests ( Figure 4). Routine laboratory test results (erythro-

Dermoscopy of Merkel Cell Carcinoma

“…To the best of our knowledge, dermoscopic studies of MCC have been reported for only 2 cases of spontaneously regressive MCC [8]. In both cases a polymorphous aspect of the vascular pattern was observed: linear irregular and regular vessels in one case and linear irregular vessels associated with a homogenous milky-red background in the second case.…”

“…Due to its red, pink or purple nodular presentation, the differential diagnosis includes cutaneous lymphoma, atypical fibroxanthoma, porocarcinoma, achromic melanoma, angiosarcoma, hemangioma or skin metastasis from internal malignancy. The dermoscopic aspect of MCC has been previously reported only in two case reports of spontaneous regressive MCC [8]. The aim of this study was to define the main dermoscopic patterns observed in MCC, to compare them with other known dermoscopic features of amelanotic malignant tumors and to address the question whether those criteria were specific or not.…”

Immunobiology of Merkel Cell Carcinoma: Implications for Immunotherapy of a Polyomavirus-Associated Cancer

“…MCC tumors sometimes regress following improvement in immune function [13, 14] underscoring the importance of immune surveillance in the development of MCC. Additionally, there are several reported cases of complete spontaneous regression in the MCC literature (a far greater number than expected for its rarity) that suggest a sudden recognition by the immune system leading to the clearance of MCC [15-20]. These epidemiologic data raised the possibility of an infectious etiology for MCC.…”

Three different dermoscopic view of three new cases with pilomatrixoma

“…White zones together with streaks were mentioned in two previously published articles. [67] Milky pink zones, linear irregular vessels and branching vessels were also demonstrated in Merkel cell carcinoma. [67] In case 1, yellowish-white zones were surrounded by crown like shaped branching vessels.…”

“…[67] Milky pink zones, linear irregular vessels and branching vessels were also demonstrated in Merkel cell carcinoma. [67] In case 1, yellowish-white zones were surrounded by crown like shaped branching vessels. These findings are also common in sebaceous hyperplasia,[8] and molluscum contagiosum.…”