Extra-uterine leiomyomata

Case contributed by Hein Els
Diagnosis certain


Known with uterine leiomyoma. Abdominal myomectomy planned, but found small uterine fibroid and large extra-peritoneal and smaller anterior abdominal wall masses. Sample taken from the anterior abdominal wall mass and further surgery abandoned in order to prevent peritoneal spread of a possible malignancy. CT performed for further assessment.

Patient Data

Age: 40 years
Gender: Female

Multiple large circumscribed masses in the space of Retzius. Most of the lesions are inseparable from each other. The majority show predominantly homogenous and avid contrast enhancement, but some of the lesions enhance heterogenously. The anterior margin of the masses infiltrates into the lower rectus muscles. Posteriorly it has mass effect on the bladder with no tissue plane separating the masses from the bladder, but the bladder wall remains continuous and enhances normally.

Multiple other smaller nodules in the subcutaneous fat of the lower abdominal wall and lower rectus muscles with similar enhancement characteristics. 

Small enhancing lesions on the left side of the uterus.

Multiple small circumscribed pulmonary nodules at the lung bases.  No evidence of other solid organ or peritoneal metastatic disease.

Photos of resected tissue


Second surgery performed after CT scan: resection of anterior abdominal wall and space of Retzius mass, subtotal hysterectomy and oophorectomy. All macroscopic diseases were removed. 


(1) Retroperitoneal mass: Four pieces of tissue, the largest one is a multilobulated mass partially opened. On sectioning the tissue has a whorled appearance.

(2) Subtotal hysterectomy and bilateral oophorectomy: An opened uterus without cervix and both attached adnexa.  The myometrium reveals small white lesions probably small fibroids. Corpus luteum present on sectioning of the right ovary.

(3) Rectus sheath: The specimen consists of two irregular fragments of brown tissue.

(4) Peritoneal nodule: A single fragment of white tissue.

(5) Aortic lymph node: A fragment of white tissue, well circumscribed.

(6) Left ileal artery lymph node: A small fragment of white tissue.


(1) Microscopic examination reveals fascicles of smooth muscle cells with focal hypercellularity. Atypia however not apparent. Mitotic activity is not abundant. Immunohistochemistry reveals the following: DOG.1 - Focal positivity within tumor cells; CD117 - Completely negative; SMA - Strong positivity within tumor cells. These findings are thus in keeping with those of a benign leiomyomata without overt evidence of atypia or necrosis.

(2) Microscopic examination reveals endometrial tissue with proliferative activity. There is no evidence of endometritis, endometrial polyps or malignancy. The myometriumn reveals adenomyosis as well as benign leiomyomata. The right fallopian tube reveals paratubal cysts. The ovary shows cystic follicles as well as a corpus luteum. The left fallopian tube is within normal limits and the left ovary reveals similar features to the right ovary. There is no overt evidence of malignancy. There is also evidence of thrombus formation in a blood vessel with organization.

(3) Microscopic examination reveals fibromuscular tissue within which a proliferation of nodules of smooth muscle cells can be identified with a vesicular appearance. Immunohistochemistry revealed the following: SMA - Strong positivity within tumor cells; DOG.1 and CD117 - Negative. These findings are in keeping with benign leioomyomata.

(4) Microscopic examination reveals fibrofatty tissue with a focus of fat necrosis and surrounding fibrosis. No smooth muscle cell proliferation can be identified.

(5) Microscopic examination reveals fibrofatty tissue within which there is evidence of fat necrosis. There is no evidence of malignancy. No lymphoid tissue could be identified.

(6) Microscopic examination reveals a lymph node with sinus histiocytosis. There is no evidence of metastatic malignancy.


(1) Retroperitoneal mass - BENIGN LEIOMYOMAS

(2) Subtotal hysterectomy: Endometrium - PROLIFERATIVE myometrium - ADENOMYOSIS - BENIGN LEIOMYOMATA; Right fallopian tube - PARATUBAL CYST; left fallopian tube - WITHIN NORMAL LIMITS; Ovaries - CORPORA ALBICANTEA - CYSTIC FOLLICLES; serosa - WITHIN NORMAL LIMITS

(3) Rectus sheath nodule - BENIGN LEIOMYOMAS

(4) Peritoneal biopsy - FAT NECROSIS

(5) Left iliac artery lymph node - FAT NECROSIS - NO LYMPHOID TISSUE IDENTIFIED


Case Discussion

Additional history obtained: patient had two prior Cesarian sections and two prior myomectomies.

The imaging features of this case show overlap of some of the uncommon growth patterns described in the radiologic literature. The anterior abdominal wall and space of Retzius leiomyomas are likely disseminated along the tract of previous myomectomies (x2). Like parasitic leiomyomas, these lesions likely developed an auxillary blood supply from the tissues in which they were seeded. The pulmonary nodules (in this case) have not been proven to be leiomyomas, but are suggestive of leiomyomas given the other findings. Pulmonary leiomyomas are usually seen in the setting of benign metastasizing leiomyomatosis. 


With thanks to: Drs. E. Van der Merwe, J. Deale, C. Struwig, K. Brundyn, J. Greyling, B. Van der Merwe.

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