RT Book, Section
A1 Müller, Hansgeorg
A1 Kutzner, Heinz
A2 Kang, Sewon
A2 Amagai, Masayuki
A2 Bruckner, Anna L.
A2 Enk, Alexander H.
A2 Margolis, David J.
A2 McMichael, Amy J.
A2 Orringer, Jeffrey S.
SR Print(0)
ID 1161337635
T1 Neoplasias and Hyperplasias of Muscular and Neural Origin
T2 Fitzpatrick's Dermatology, 9e
YR 2019
FD 2019
PB McGraw-Hill Education
PP New York, NY
SN 9780071837798
LK dermatology.mhmedical.com/content.aspx?aid=1161337635
RD 2024/04/19
AB Cutaneous  tumors  with  smooth  muscle  differentiation  Table  121-1)  can  be  categorized  according  to  their  microanatomical  origin:  (a)  arrector  pili  muscles,  (b)  smooth  muscle  of  genital  skin,  including  scrotum  (dartos  muscle),  vulva,  nipple  and  areolar  region,  and  (c)  walls  of  blood  vessels.  Each  of  these  sources  of  smooth  muscle  can  give  rise  to  benign  superficial  smooth  muscle  tumors  (leiomyomas)  as  well  as  their  malignant  counterparts  (leiomyosarcomas).1  Anecdotally,  smooth  muscle  also  has  been  reported  in  organoid  and  blue  nevi.2  Of  note,  smooth  muscle  tumors  arising  in  deep  soft  tissues  (eg,  abdominal  cavity,  pelvis,  retroperitoneum),  and  visceral  organs  (including  uterine  tumors)  often  show  overlapping  morphologic  and  immunohistochemical  features  with  cutaneous  tumors,  but  form  different  clinicopathologic  categories  because  biologic  potential,  clinical  prognosis,  and  criteria  for  malignancy  depend  primarily  on  location.3,4  Histologically,  the  constituent  cells  of  smooth  muscle  lesions  are  spindled  and  contain  abundant  brightly  eosinophilic  cytoplasm  as  well  as  blunt-ended  (cigar-shaped)  nuclei.  Smooth  muscle  antigens,  including  α-smooth  muscle  actin  (α-SMA),  muscle-specific  actin,  desmin,  and  h-caldesmon  are  readily  identified  by  immunohistochemistry.  Atypical  intradermal  smooth  muscle  neoplasms  and  leiomyosarcomas  often  at  least  focally  express  epithelial  markers,  and  sporadic  cases  may  express  S-100  protein.5,6Figure  121-1  provides  an  overview  of  the  diagnosis  of  cutaneous  tumors  with  smooth  muscle  differentiation.  The  spectrum  of  cutaneous  smooth  muscle  lesions  includes  leiomyomas,  leiomyosarcomas,  and  smooth  muscle  hamartomas.