Uterine leiomyomas can occur in different locations within the pelvis and uterus, including submucosal, intramural, and subserosal forms, as well as parasitic and intravenous types that extend into other organs. Rare variants include diffuse leiomyomatosis with multiple small nodules throughout the enlarged uterus, as well as benign metastasizing leiomyomas that can spread to distant sites like the lungs after hysterectomy for uterine leiomyomas.

1. Uterine leiomyoma - locations
Submucosal
Intramural
Subserosal
Parasitic
free within pelvis/still attached to uterus by a stalk, with blood supply
from nearby structures
Diffuse leiomyomatosis
enlarged uterus with multiple small ill-defined T2 hypointense nodules
Intravenous leiomyomatosis
extending from uterus to uterine vein, iliac, IVC, heart

2. Leiomyoma – other gynecologic locations
Broad ligament – no attachment to uterus
Fallopian tube
between uterus and ovary, with rim sign on T1 Gad FS
Ovarian – claw sign
Benign metastasizing leiomyoma
hematogeneous dissemination after hysterectomy for leiomyomas
most frequently to lungs
Disseminated peritoneal leiomyomatosis
nodules which mimic peritoneal carcinomatosis,
but there is no infiltration, ascites, or liver mets
From Diagnostic Imaging: Gynecology. 1st edition. 2007