Table of Contents
Definition / general | Terminology | Epidemiology | Case reports | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Differential diagnosisCite this page: Shankar V. Leiomyoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/softtissueleiomyoma.html. Accessed March 4th, 2021.
Definition / general
- Bland smooth muscle tumor without mitotic figures (eMedicine)
Terminology
- Not a WHO diagnosis (cutaneous and pilar tumors are described in the Skin volume)
- Some tumors previously considered to be leiomyomas are actually GI stromal (GIST) tumors
- See also colon-tumor, esophagus, uterus chapters
Epidemiology
- Skin and subcutis; also deep soft tissue, uterus (most common neoplasm in women)
- Patients with multiple cutaneous leiomyomas may have autosomal dominant disorder (described under Cutaneous leiomyoma)
Case reports
- 34 year old man with sickle cell thalassemia and ossified leiomyoma (J Cutan Pathol 2005;32:696)
- 59 year old woman with finger lesion (Chang Gung Med J 2004;27:134)
Microscopic (histologic) description
- Bundles or fascicles of spindled cells with eosinophilic and possibly fibrillary cytoplasm
- Nuclei are blunt ended and elongated with fine chromatin, indistinct nucleolus and variable cytoplasmic vacuole at one end
- Minimal atypia
- Few mitotic figures
- No coagulative tumor necrosis
Microscopic (histologic) images
Positive stains
- Desmin, alpha smooth muscle actin
- H-caldesmon, calponin, muscle specific actin, myosin
- ER and PR for uterine tumors
Differential diagnosis
- Angiomyolipoma: usually prominent vascular and lipomatous component
- Leiomyosarcoma: more cellular, infiltrative, pleomorphic; mitotic activity and coagulative tumor cell necrosis