Pigmented Spindle Cell Nevus of Reed of the Eyelid.

Purpose: To report the clinical, pathological, and immunohistochemical features of the first pigmented spindle cell nevus (PSCN) of Reed documented to have appeared in the eyelid.

Methods: The findings of clinical and histopathological examination are presented, along with differential diagnoses and a review of the pertinent literature.

Case: A 3-year-old boy presented with a rapidly growing, heavily pigmented left lower lid papule raising the concern of malignancy, warranting excisional biopsy. Nests of predominantly junctional Mart-1-positive spindle cells were identified by histopathological examination. The cells were largely uniform in size, elongated, surrounded by granular and coarse melanin, with a Ki-67 proliferation index of 0-2%. Five-month follow-up did not evidence any recurrence or invasive behavior of this benign melanocytic tumor.

Conclusion: This is the first documented case of PSCN of Reed, a distinct entity from Spitz nevus, presenting in the eyelid. The differential diagnoses include spindle cell and superficially spreading malignant melanoma as well as dysplastic nevus. Integration of clinical and histopathological findings with immunohistochemical and fluorescence in situ hybridization markers plays a central role in the diagnosis.