Merkel cell (primary neuroendocrine) carcinoma of the skin with nodal metastasis showing rhabdomyosarcomatous differentiation
Article first published online: 9 DEC 2002
Journal of Cutaneous Pathology
Volume 29, Issue 10, pages 619–622, November 2002
How to Cite
Fernández-Figueras, M.-T., Puig, L., Gilaberte, M., Del Carmen Gómez-Plaza, M., Rex, J., Ferrándiz, C. and Ariza, A. (2002), Merkel cell (primary neuroendocrine) carcinoma of the skin with nodal metastasis showing rhabdomyosarcomatous differentiation. Journal of Cutaneous Pathology, 29: 619–622. doi: 10.1034/j.1600-0560.2002.291010.x
- Issue published online: 9 DEC 2002
- Article first published online: 9 DEC 2002
- Accepted September 15, 2001
Background: We describe a unique case of Merkel cell (primary neuroendocrine) carcinoma of the skin with a lymph node metastasis showing rhabdomyosarcomatous differentiation. Skeletal muscle differentiation has occasionally been described in primary small cell neuroendocrine carcinomas and considered a form of dual differentiation rather than a collision tumor. In the present case, capacity for divergent differentiation appeared late in the course of the tumor, which suggests a clonal origin for both components of the neoplasm.
Conclusions: The coexistence of neural and rhabdomyoblastic types of differentiation, best epitomized by the Triton tumor, has been construed as the product of dual differentiation of cells originated from neural crest-derived ectomesenchyme. Since Merkel cells seem to originate from a pluripotential primitive keratinocyte and not from the neural crest, rhabdomyoblastic differentiation in a metastasis of primary neuroendocrine carcinoma of the skin probably reflects the close proximity between the programs of neural and skeletal muscle differentiation, which would have been sequentially activated in the case we are reporting.