Melanocytic matricoma: case confirmation of a recently described entity.
BACKGROUND
In 1999, Carlson et al. reported two cases of a matrical neoplasm that recapitulates the bulb of the anagen hair follicle, which they designated as melanocytic matricoma.


METHODS
Here we report a similar case in a 78-year-old white male, who presented with a 0.4 cm purple-black firm papule in the left preauricular area.


RESULTS
Histologically, the tumor is composed of a dual cell population including admixed epithelial matrical and supramatrical cells with "shadow" cell formation and pigmented dendritic melanocytes. Immunohistochemical studies for cytokeratin highlighted the epithelial component and studies for S-100 protein, HMB-45, and vimentin confirmed the melanocytic component. The differential diagnosis considered includes pigmented variants of pilomatricoma, matrical carcinoma, basal cell carcinoma and malignant melanoma.


CONCLUSIONS
The case reported herein is the first confirmation of melanocytic matricoma, a distinctive adnexal neoplasm with characteristic clinical and pathologic features, which differentiate it from pigmented pilomatricoma.
Williams
Christy M
CM
Department of Pathology, University of South Alabama, Mobile, Alabama, USA.
Bozner
Peter
P
Oliveri
Cecilia V
CV
Horenstein
Marcelo G
MG
D000368:Aged; D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor / Q000378:metabolism; D006201:Hair Diseases / Q000378:metabolism / Q000473:pathology*; D018859:Hair Follicle / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008297:Male; D008544:Melanocytes / Q000378:metabolism / Q000473:pathology*; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins / Q000378:metabolism; D018294:Neoplasms, Adnexal and Skin Appendage / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D018296:Pilomatrixoma / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D009418:S100 Proteins / Q000378:metabolism; D012878:Skin Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D014746:Vimentin / Q000378:metabolism
D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins; D009418:S100 Proteins; D014746:Vimentin