Sunday, May 29, 2011

Lymphangioleiomyoma

Lymphangioleiomyomas are proliferations of smooth muscle cells in lymphatic vessels, leading to obstruction and dilation that results in cystic collections of chyle. They can be seen in about 15% of patients with lymphangioleiomyomatosis (LAM).

These dilated retroperitoneal lymphatic vessels can present as thick- or thin-walled masses with or without central low attenuation (~5 HU to 25 HU). Rupture may result in chylous ascites (-10 HU to 20 HU).

Isolated retroperitonel involvement can cause a diagnostic dilemma. Differential considerations in these cases include:
  • Enlarged lymph nodes: Enlarged nodes may be seen in patients with LAM, and some of these lymph nodes have central areas of low attenuation (−70 HU to 50 HU).
  • Cystic lymphangioma:
  • Neoplasm: Lymphoma or metastases. Primary cystic retroperitoneal tumors (liposarcoma, leiomyosarcoma, and fibrosarcoma) with cystic degeneration will usually have solid components.
  • Fluid collections: Old hematoma, abscess, urinoma, and lymphoceles.
Thanks to Dr. Mark Bankoff for the case.

References

Avila NA, Kelly JA, Chu SC, Dwyer AJ, Moss J. Lymphangioleiomyomatosis: abdominopelvic CT and US findings. Radiology. 2000 Jul;216(1):147-53.

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