Desmoid Tumor in 11 Year Old Male

History

A previously healthy 11 year old male was referred for a hypertension workup. The physician felt a palpable abdominal mass and requested an abdominal sonogram.

Findings

Abdominal sonography demonstrated a single, lobulated solid mass, measuring 17 cm x 10 cm x 25 cm. It occupied the lower abdomen and pelvic cavity. The mass appeared heterogeneous with moderate blood flow. The IVC was compressed. No enlarged lymph nodes were identified.

CT of the chest, abdomen, and pelvis demonstrated a massive, circumscribed intra-abdominal mass, displacing the major vessels without encasement. The mass appeared to be separate from the bladder wall and kidneys.

Differential Diagnosis

Differential diagnoses included rhabdomyosarcoma, lymphoma, desmoid or GI stromal tumor. Neuroblastoma was less favored as no internal calcifications were seen and there was displacement of the major vessels without encasement.

An ultrasound-guided needle biopsy was performed the following day.

Surgical excision was performed one month later.

Diagnosis

The needle biopsy specimen revealed dense fibroconnective tissue with scattered blood vessels seen throughout. No malignant cells were recognized. This benign fibroblastic lesion was consistent with a desmoid tumor.

The surgically excised specimen consisted of a firm, encapsulated mass weighing 1430 grams. It appeared to arise from the mesenteric side of the intestine.

Surgical

Upon entering the patient's abdomen the mass was noted to arise from the mensentary with the sigmoid colon draped anteriorly. The mensentary of the sigmoid colon was almost completely obliterated with the mass gaining some of its blood supply from the mensentary, some from the greater omentum, and some from small pedicles off of the mensentary proper. The sigmoid colon and the mass were resected en bloc and a primary anastomosis of the colon was performed.

General Discussion

Desmoid tumors of the abdomen, also called aggressive fibromatosis when found in the extremities, is a histologically benign tumor made up of firm fibrous connective tissue. Although it does not metastasize to other parts of the body, it is often difficult to control because it insinuates into surrounding tissues, adhering firmly to adjacent organs and structures.

A desmoid tumor may occur anywhere in the body. a recent review of 63 pediatric cases found site distribution as follows: 61% extremities, 18% head and neck, 13% trunk (including 5% intra-abdominal), and 8% multicentric. Ref 1. Its exact cause is unknown, but may be related to trauma or hormonal factors, or may have a genetic association.

These tumors more commonly occur in patients who have a history of polyposis coli, a hereditary colon cancer syndrome.

These benign tumors are more common in persons 10-40 years of age, and occur twice as often in females than males. Overall, desmoid tumors account for 0.03% of all neoplasms. A desmoid tumor may exist for some time before being discovered, growing large and displacing surrounding tissue.

Symptoms may include:

• A painless swelling or lump
• Pain caused by compressed nerves or muscles
• Bowel obstruction when tumors originate in the abdomen
• Limping when tumors occur in the lower extremities

Surgical excision with negative surgical margins is the mainstay of treatment; however, up to 70% of desmoid tumors recur after surgery. Additional treatment includes anti-inflammatory medication, radiation therapy, hormone therapy, and chemotherapy.

Equipment Summary

Exam was performed on Toshiba's Aplio™ XG ultrasound system utilizing a 5 MHz multifrequency transducer and Toshiba's exclusive Differential Tissue Harmonic Imaging technology.

References

1. Faulkner L.B., et al., Pediatric desmoid tumor: retrospective analysis of 63 cases. J Clin Oncol, 1995. 13(11): p. 2813-8.
2. Definition of Desmoid Tumor. 2003 5/19/2003 [cited 2008 08/12/2008]; Available from: www.medterms.com/script/main/art.asp?articlekey=9378.
3. Desmoid Tumor. 2008 8/12/2008 [cited 2008 08/12/2008]; Available from: www.childrenshospital.org/az/Site703/mainpageS703PO.html.
4. Schwartz RA, T.M., Lambert PC (2008) Desmoid Tumor. Volume, 12.
5. Sarcomas. 2007 May 8, 2007 [cited 2007 08/12/2008]; Available from: www.ucsfhealth.org/childrens/medical_services/cancer/sarcomas/conditions/desmoid.