title: Apocrine mixed tumor of the skin ("mixed tumor of the folliculosebaceous-apocrine complex"). Spectrum of differentiations and metaplastic changes in the epithelial, myoepithelial, and stromal components based on a histopathologic study of 244 cases.
abstract: BACKGROUND
  A systematic analysis of the entire spectrum of various forms of differentiation and metaplastic epiphenomena in cutaneous apocrine mixed tumor (AMT) has never been performed.
  
  
  OBJECTIVE
  The purpose of our study was to study a large number of cutaneous mixed tumors so as to fully characterize the entire spectrum of differentiations and metaplastic changes that may occur in the epithelial, myoepithelial, and stromal components of AMT.
  
  
  METHODS
  This article reports a light-microscopic study of 244 cases of cutaneous AMT, complemented by a literature review.
  
  
  RESULTS
  All types of differentiation along the lines of the folliculosebaceous-apocrine unit can be seen in AMT. The spectrum of metaplastic changes in the epithelial components includes squamous metaplasia, mucinous metaplasia, oxyphilic metaplasia, clear cell change, columnar metaplasia, hobnail metaplasia, and cytoplasmic vacuolization. The following changes in the myoepithelial component were documented: clear cell change, hyaline cells, plasmacytoid cells, spindling, and collagenous spherulosis. Stromal alterations included chondroid metaplasia, osseous metaplasia, and adipose metaplasia.
  
  
  CONCLUSIONS
  This study utilizes tissue specimens that mainly came as consultations; therefore some inherent selection bias exists.
  
  
  CONCLUSIONS
  AMT displays a wide range of differentiation and metaplastic changes in its epithelial, myoepithelial, and stromal components. These phenomena are not mutually exclusive. When unduly prominent, they may present diagnostic pitfalls. Our findings corroborate those of previous publications, stressing the remarkable diversity of differentiation and metaplasias that may be found in cutaneous AMT. We propose that the most appropriate name for these lesions is "mixed tumor of the folliculosebaceous-apocrine complex."
authors: Sikl's Department of Pathology, Charles University Medical Faculty Hospital, Pilsen, Czech Republic. kazakov@medima.cz
authors: Dmitry V
authors: DV
authors: Kazakov
authors: Irena E
authors: IE
authors: Belousova
authors: Michele
authors: M
authors: Bisceglia
authors: Eduardo
authors: E
authors: Calonje
authors: Michael
authors: M
authors: Emberger
authors: Wayne
authors: W
authors: Grayson
authors: Markus
authors: M
authors: Hantschke
authors: Werner
authors: W
authors: Kempf
authors: Heinz
authors: H
authors: Kutzner
authors: Michal
authors: M
authors: Michal
authors: Dominic V
authors: DV
authors: Spagnolo
authors: Susanna
authors: S
authors: Virolainen
authors: Bernhard
authors: B
authors: Zelger
mesh_terms: D008949:Adenoma, Pleomorphic / Q000473:pathology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D001050:Apocrine Glands / Q000473:pathology; D002454:Cell Differentiation; D002648:Child; D004848:Epithelium / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008679:Metaplasia; D008875:Middle Aged; D012627:Sebaceous Glands / Q000473:pathology; D012878:Skin Neoplasms / Q000473:pathology*; D013544:Sweat Gland Neoplasms / Q000473:pathology*