title: MITF positivity in atypical fibroxanthoma: a diagnostic pitfall.
abstract: Microphthalmia transcription factor (MITF) is an established melanocytic marker originally credited with a high degree of specificity. We report a series of 11 atypical fibroxanthoma (AFX) from 2 laboratories showing positive MITF staining. Although there are multiple case reports illustrating MITF staining in a range of tumors, aberrant staining in AFX has not been previously reported. Awareness of the possibility of MITF positivity in AFX is important to avoid a misdiagnosis of melanoma. We also report positive MITF staining in 2 nonneural granular cell tumors and discuss the overlap with the granular subtype of AFX.
authors.affiliation: *Dermatopathology division, Pathlab Bay of Plenty, Tauranga; Da Vinci Clinic, Tauranga, New Zealand; and †Clinipath Pathology, West Perth, Australia.
authors.forename: Ben
authors.initials: B
authors.lastname: Tallon
authors.forename: Trevor W
authors.initials: TW
authors.lastname: Beer
authors.forename: Trevor M
authors.initials: TM
authors.lastname: Beer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis; D001706:Biopsy; D003951:Diagnostic Errors / Q000517:prevention & control; D005260:Female; D005350:Fibroma / Q000737:chemistry* / Q000209:etiology / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008545:Melanoma / Q000737:chemistry / Q000473:pathology; D051739:Microphthalmia-Associated Transcription Factor / Q000032:analysis*; D008875:Middle Aged; D009381:Neoplasms, Radiation-Induced / Q000737:chemistry* / Q000209:etiology / Q000473:pathology; D009520:New Zealand; D011237:Predictive Value of Tests; D012878:Skin Neoplasms / Q000737:chemistry* / Q000209:etiology / Q000473:pathology; D013472:Sunlight / Q000009:adverse effects
chemical_list: D014408:Biomarkers, Tumor; C497234:MITF protein, human; D051739:Microphthalmia-Associated Transcription Factor