title: Folliculotropic T-cell lymphocytosis as a distinct form of pilotropic T-cell dyscrasia.
abstract: Cutaneous T-cell dyscrasia represents a heterogeneous group of persistent clonal and usually epitheliotropic T-cell infiltrates with a seemingly low risk for progression to mycosis fungoides (MF). Mucin-poor folliculotropic T-cell lymphocytosis is the least well characterized with only a few anecdotal case reports. Cases of folliculotropic lymphocytosis were retrieved via a natural language search from 2 dermatopathology databases. Comprehensive light microscopic, phenotypic, and molecular studies were conducted. There were 12 females and 12 males, with mean age of 41 years. There were 2 main clinical presentations: facial erythematous infiltrative papules and/or nodules vs extremity and truncal solitary, large, scaly plaques. The mean duration of the lesions was 3 years. Progression to follicular MF was noted in 1 case. Migration of small lymphocytes into the superficial portions of the hair follicle unaccompanied by other inflammatory cells or mucin was observed; lymphocytes with a cerebriform appearance could be seen. The CD4/CD8 ratio was more than 5:1 with significant reductions in the expression of CD62L and CD7. Of 20 cases tested, 5 showed monoclonality. Folliculotropic T-cell lymphocytosis is a form of pilotropic T-cell dyscrasia distinct from MF and alopecia mucinosa; the course seems indolent in most cases.
authors.affiliation: Dept of Pathology, Weill Cornell Medical College, New York, NY 10065, USA.
authors.forename: Cynthia M
authors.initials: CM
authors.lastname: Magro
authors.forename: A Neil
authors.initials: AN
authors.lastname: Crowson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D005260:Female; D018859:Hair Follicle / Q000473:pathology*; D006801:Humans; D006965:Hyperplasia / Q000473:pathology; D008218:Lymphocytosis / Q000150:complications / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009182:Mycosis Fungoides / Q000209:etiology / Q000473:pathology; D012867:Skin / Q000473:pathology*; D013601:T-Lymphocytes / Q000473:pathology*