Primary cutaneous ganglioneuroma: anatomico‐clinical study of 4 cases with focus on Merkel cells

Abstract

Cutaneous ganglioneuromas (CGNs) are exceptional. We aim to describe the anatomico-clinical profile of primary CGN and report 4 cases. Patients were 2 men and 2 women aged 53 to 76 years, who had flesh-colored nodules on the back, associated with adjacent keratotic changes, that is, epidermal nevus (1 case) or seborrheic keratosis (3 cases). Histopathology showed ganglion cells within a proliferation of Schwann cells. The epidermis was acanthotic, associated with sebaceous induction in 2 cases, with follicular hyperplasia as in fibroepithelial tumors (1 case) or with tricholemmoma (2 cases). Cytokeratin-20 immunostaining showed Merkel cells in the epidermis. A higher density of Merkel cells was observed in BerEP4+ follicular structures. Along with 16 published cases, our study indicates that a nodule associated with seborrheic keratosis on the back may represent a CGN, a complex mesenchymal and epidermal/follicular lesion of neuroectodermal lineage, associating neuronal proliferation and Merkel cell hyperplasia with follicular induction.

Cutaneous ganglioneuroma: A case report and discussion of the literature

“…The more widely accepted view is that there is a cellular interaction between the ganglion cells and adjacent keratinocytes that induces epidermal hyperplasia and papillomatosis, consistent with the appearance of a seborrheic keratosis . There have also been case reports demonstrating associations with congenital nevi, verucca vulgaris, epidermal nevi, and trichilemmomas (see Table ) . Interestingly, all of these entities exhibit some degree of epidermal hyperplasia, hyperkeratosis, and papillomatosis clinically and on histopathological examination.…”

“…Most often, cutaneous GN presents as a solitary, well‐circumscribed, round, firm nodule that contains a smooth fibrous capsule . A review of reported cases reveals that they are slightly more common in females, grow slowly, have little to no malignant potential, and can vary from a few millimeters to several centimeters . The most common location for GNs is the trunk .…”

“…There are thought to be multiple mechanisms which lead to the development of cutaneous GNs. One thought is that there is an ectopic migration of neural crest cells that end up in the skin . Another possible pathogenesis is maturation of neuroblastomas and ganglioblastomas into GNs .…”