Neurotized melanocytic nevus (NMN) is categorized into intradermal/intramucosal type of acquired melanocytic nevus. In contrast to typical intramucosal nevus which has relatively distinct histological features, the diagnosis of NMN requires more attention due to its mimicry of benign neural tumors such as neurofibroma. The majority of lesional cells, NMN cells, showed a spindle cell morphology and abundant, eosinophilic cytoplasm which were positive for S-100, vimentin, and collagen type IV. Positive reaction for MART-1 was detected in the NMN cells as well as in the epithelioid nevus cells beneath the epithelium. Neurofibroma exhibited diffuse positivity for S-100, vimentin, CD34 and collagen type IV, but never expressed MART-1. Toluidine blue stained the numerous mast cells scattered in the lesion of neurofibroma, compared to the relatively minor detection of mast cells in NMN. Therefore, MART-1 is a useful marker in differentiating NMN from neurofibroma.

Ⅰ. Introduction
 II. Material and Method
 III. Results
  1. Case history
  2. Clinical findings
  3. Histopathologic findings
  4. Findings of immunohistochemical and specialstaining.
 IV. Discussion
 V. Conclusion
 Ⅵ. References

• 박현도(Department of Oral Pathology, School of Dentistry, Seoul National University) | Hyun Do Park
• 조영아(Department of Oral Pathology, School of Dentistry, Seoul National University) | Young Ah Cho
• 신의정(Department of Oral Pathology, School of Dentistry, Seoul National University) | Wui Jung Shin
• 홍성두(Department of Oral Pathology, School of Dentistry, Seoul National University) | Seong Doo Hong
• 이재일(Department of Oral Pathology, School of Dentistry, Seoul National University) | Jae Il Lee
• 홍삼표(Department of Oral Pathology, School of Dentistry, Seoul National University) | Sam Pyo Hong
• 윤혜정(Department of Oral Pathology, School of Dentistry, Seoul National University) | Hye Jung Yoon correspondence