Background: Cutaneous metastasis from neuroendocrine carcinomas of visceral origin is rarely described in indexed literature. The primary sites of origin include: lung (Wick et al., J Am Acad Dermatol 1985; 13: 134), larynx (Zambruno et al., Ann Dermatol Venereol 1989; 116: 855; Schmidt et al., J Laryngol Otol 1994; 108: 272; Guerzider et al., Ann Pathol 1991; 11 (4): 253), mediastinum (Yoshimasu et al., J Dermatol 2001; 28 (3): 168), uterus (Fogaca et al., J Cutan Pathol 1993; 20: 455), and thymus (Wick et al., J Am Acad Dermatol 1985; 13: 134).
Methods: In this report, the authors present the clinical, histological, immunohistochemical, and ultrastructural characteristics of secondary skin localizations of a neuroendocrine laryngeal tumor that occurred in a 61-year-old man. The complete follow up of the case is described and a brief revision of the terminology and classification of neuroendocrine neoplasms of the larynx is discussed, since a significant relationship exists between the degree of differentiation and biological behavior.
Results: On histological examination, the secondary cutaneous localization appeared to be more dedifferentiated compared to the primary tumor. The immunohistochemical patterns of reactivity were similar in both neoplasms, showing expression of neuroendocrine and epithelial markers.
Conclusions: An important issue of prognostic significance is to differentiate a cutaneous metastasis of a neuroendocrine carcinoma from the primary small cell-undifferentiated carcinoma of the skin (Merkel cell carcinoma).