The number and distribution of Merkel cells in rudimentary polydactyly.

BACKGROUND: Rudimentary polydactyly histologically reveals a marked neural proliferation in the dermis and a large number of Meissner corpuscles in the dermal papillae.

OBJECTIVE: Our study was performed to determine whether this neural proliferation is related to Merkel cells.

METHOD: Using an antibody to cytokeratin 20, we examined the number and distribution of Merkel cells in 5 cases of rudimentary polydactyly, including an immature case without Meissner corpuscles.

RESULTS: Only the case without Meissner corpuscles had a markedly large number of Merkel cells and some dermal Merkel cells.

CONCLUSION: The normal number of Merkel cells in the mature cases suggests that abundant Merkel cells may appear at first and disappear after the development of neural proliferation. Merkel cells may be associated with the generation of cutaneous nerve plexus and nerve endings in the upper dermis, and possibly with the development of Meissner corpuscles, at the early stage of rudimentary polydactyly.