Arch Craniofac Surg.  2019 Apr;20(2):139-143. 10.7181/acfs.2019.00045.

Atypical proliferative nodule in congenital melanocytic nevus with dural invasion: a case report

• Jung JH
• Jang KT
• Kim A
• Lim SY

• KMID: 2447640
• DOI: http://doi.org/10.7181/acfs.2019.00045

Abstract

Here we report a case of a focal atypical proliferative nodule (PN) arising from a congenital melanocytic nevus (CMN). Diagnosis was challenging because it had both benign and malignant clinical features. Unusual histopathology, immunohistochemistry, and intraoperative findings of this atypical PN are discussed. A 5-year-old girl was admitted for a congenital 5× 5 cm sized scalp mass. This hemangioma-like soft mass showed biphasic characteristics such as a slow, gradual, and benign increase in size but worrisome dural invasion with cranial bone defect. We removed the scalp mass with clear resection margins. Interoperatively, we found that the cranial bone defect had already filled. Histopathologic examination showed CMN with focal atypical PN. The nodule showed sharp demarcation and cellular pleomorphism. However, in immunohistochemical study, Ki-67 proliferation index and expression levels of protein S-100 and Melan-A were very low. These were unusual findings of atypical PNs. Despite her worrisome preoperative radiologic features, she showed an indolent clinical course compatible with previously reported biologic behavior. The patient underwent follow-up inspection with magnetic resonance imaging every 6 months for up to 3 years. The nodule appeared to be stationary at the last visit.

Keyword

Dura mater; Melanocytic nevus syndrome, congenital; Neoplasm invasiveness; Tissue expansion devices

MeSH Terms

Child, Preschool
Diagnosis
Dura Mater
Female
Follow-Up Studies
Humans
Immunohistochemistry
Magnetic Resonance Imaging
MART-1 Antigen
Neoplasm Invasiveness
Nevus, Pigmented*
Scalp
Tissue Expansion Devices
MART-1 Antigen