TY  - CHAP
M1  - Book, Section
TI  - Pilomatricoma and Pilomatrix Carcinoma
A1  - Chan, Edward F.
A1  - Gat, Uri
A1  - Dasgupta, Ramanuj
A1  - Fuchs, Elaine
A2  - Valle, David L.
A2  - Antonarakis, Stylianos
A2  - Ballabio, Andrea
A2  - Beaudet, Arthur L.
A2  - Mitchell, Grant A.
Y1  - 2019
N1  - 10.1036/ommbid.370
T2  - The Online Metabolic and Molecular Bases of Inherited Disease
AB  - Pilomatricoma  is  a  benign  hair  follicle  tumor  that  is  thought  to  be  the  most  common  solid  cutaneous  tumor  in  patients  20  years  of  age  or  younger.  It  demonstrates  differentiation  toward  the  compartment  of  cells  in  the  matrix  of  the  hair  bulb  that  forms  the  hair  shaft.  These  tumors  typically  present  as  solitary,  firm  nodules  on  the  head,  neck,  and  upper  extremities.  Multiple  pilomatricomas  are  found  in  4  percent  of  cases.  There  is  a  bimodal  age  of  presentation,  with  most  cases  occurring  in  the  first  and  sixth  decades.  In  patients  younger  than  20  years  of  age,  there  is  a  male:female  ratio  of  1:2.5.Pilomatrix  carcinoma  is  relatively  rare;  there  have  been  approximately  70  reports  in  the  literature.  Unlike  pilomatricomas,  pilomatrix  carcinomas  have  a  male:female  ratio  of  2:1  and  occur  at  a  later  age,  with  a  mean  age  of  48.  This  tumor  may  have  an  invasive  growth  pattern,  with  spread  into  the  underlying  bone.  Local  recurrence  occurs  in  60  percent  of  cases  and  metastatic  disease  occurs  in  10  percent  of  cases.The  histologic  appearance  of  a  pilomatricoma  is  of  a  well-circumscribed  tumor  in  the  lower  dermis  to  subcutis  comprised  of  coalescing,  irregularly  shaped  islands  of  epithelial  cells.  Two  basic  cell  types  form  these  epithelial  islands:  basophilic  cells  and  eosinophilic  shadow  cells.  The  basophilic  cells  tend  to  be  at  the  periphery  or  sides  of  the  tumor  islands  and  possess  scant  cytoplasm,  indistinct  cell  borders,  basophilic  and  hyperchromatic  nuclei,  and  numerous  mitoses.  The  eosinophilic  shadow  cells  are  at  the  center  of  the  tumor  and  show  distinct  cell  borders,  faintly  eosinophilic  cytoplasm,  and  a  central  oval  clear  area  which  is  a  shadow  of  the  lost  nucleus.  These  shadow  cells  form  from  the  basophilic  cells  and  there  may  be  a  transition  zone  where  the  basophilic  cells  become  more  eosinophilic  with  development  of  pyknotic  nuclei.  There  are  often  foci  of  calcification  and  ossification  associated  with  the  shadow  cells.In  pilomatrix  carcinoma,  there  are  large,  anaplastic,  hyperchromatic  basophilic  cells  with  numerous  mitoses,  some  of  which  may  be  atypical.  The  basophilic  cells  show  variation  in  nuclear  size,  with  coarse  chromatin,  and  prominent  nucleoli.  There  are  cystic  areas  with  central  necrosis  and  shadow  cells.  Vascular  and  perineural  invasion  may  also  be  present.Some  syndromes  involve  pilomatricomas  as  one  of  several  complex  traits.  These  disorders  include  myotonic  dystrophy,  Gardner  syndrome,  and  the  Rubinstein-Taybi  syndrome.  In  addition,  there  are  reported  cases  of  familial  pilomatricomas  without  other  systemic  manifestations.  In  contrast  to  the  sporadic  cases  of  pilomatricoma  in  which  a  solitary  lesion  is  typical,  in  the  case  of  familial  pilomatricomas,  the  tumors  are  often  multiple.A  high  percentage  of  pilomatricomas  possess  β-catenin  missense  mutations  clustered  in  the  amino-terminal  segment,  normally  involved  in  phosphorylation-dependent,  ubiquitin-mediated  degradation  of  the  protein.  The  initial  work  that  led  to  this  finding  developed  from  the  observation  that  similar  tumors  develop  in  transgenic  mice  expressing  a  keratin  promoter-driven,  stable  form  of  β-catenin  truncated  at  its  amino  terminus.  In  addition,  nuclear  LEF-1  is  present  in  the  basophilic  cells  of  the  tumor,  thus  providing  further  biochemical  evidence  that  pilomatricomas  are  derived  from  hair  matrix  cells.  These  findings  point  to  ...
SN  - 
PB  - McGraw-Hill Education
CY  - New York, NY
M3  - doi: 10.1036/ommbid.370
Y2  - 2024/04/19
UR  - ommbid.mhmedical.com/content.aspx?aid=1181418297
ER  -