Soft tissue

Smooth muscle


Leiomyoma of deep soft tissue

Last author update: 1 November 2012
Last staff update: 8 March 2022

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PubMed Search: Leiomyoma of deep soft tissue

Vijay Shankar, M.D.
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Cite this page: Shankar V. Leiomyoma of deep soft tissue. website. Accessed August 13th, 2022.
Definition / general
  • Very rare tumor of deep subcutis or skeletal muscle of extremities (Stanford University) or retroperitoneum (described below)
  • By definition, is distinct from uterus
  • Tumors of deep somatic soft tissue affect males and females equally (Am J Surg Pathol 2001;25:1134)
  • Tumors of retroperitoneum (described below) almost always occur in women
  • Can rarely occur in children
Case reports
  • Excision; rarely recurs
Clinical images

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Hand mass:
intraoperative and
gross specimen

Gross description
  • Well circumscribed, gray-white
  • Usually large at presentation, up to 15 cm
  • May have myxoid change
Gross images

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Leiomyoma of deep soft tissue

Leiomyoma of deep soft tissue

Microscopic (histologic) description
  • Fascicles of normal appearing smooth muscle with eosinophilic cytoplasm
  • Nuclei are bland and uniform, blunt ended, cigar shaped
  • May have dystrophic calcification, degenerative nuclear changes or necrobiotic nodules resembling giant rosettes
  • Hyalinization and fatty differentiation can also be seen rarely
  • No / minimal atypia
  • No / rare mitotic figures (Am J Surg Pathol 1994;18:576); < 1 per 50 HPF
  • No necrosis
Cytology description
  • Hypocellular smears, with scattered clusters of spindle cells (Diagn Cytopathol 1997;16:326)
  • Clustered cells have syncytial appearance
  • Bland nuclei have spindled appearance with rounded ends, condensed chromatin
  • Usually no necrosis or inflammation
  • No mitotic figures
Positive stains
Negative stains
Differential diagnosis
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