Discussion of Peliosis hepatis
- Peliosis hepatis (AKA hepatic peliosis) is a rare benign disorder causing sinusoidal dilatation and the presence of multiple blood-filled lacunar spaces within the liver.
- "Peliosis" is a term derived from the Greek pelios, which means "dusky" or "purple," referring to the color of the liver parenchyma with peliosis.
- The lesions typically involve the entire liver.
- Peliosis hepatis usually develops in adults.
- The cause of peliosis hepatis can be related to:
- Drugs (including anabolic steroids, oral contraceptives, corticosteroids, tamoxifen, diethylstilbestrol)
- Toxins (polyvinyl chloride, arsenic, and thorium oxide)
- Chronic wasting diseases (e.g., tuberculosis, leprosy, and various malignancies, particularly hepatocellular carcinoma)
- Infection in AIDS (so-called bacillary peliosis caused by Bartonella henselae and Bartonella quintana).
- Several other conditions are described as associated with peliosis hepatis, including sprue, diabetes mellitus, necrotizing vasculitis, and hematologic disorders.
- In 20-50% of patients, no associated condition is identified.
- The natural course of peliosis hepatis is regression after drug withdrawal, cessation of steroid therapy, or resolution of an associated infectious disease.
- Complications associated with peliosis hepatis include liver failure, portal hypertension, and liver rupture leading to hemoperitoneum or shock.
- In general, if untreated, peliosis hepatis may be rapidly fatal.
 Imaging Findings for Peliosis hepatis
- On contrast-enhanced CT, peliotic lesions can be hypoattenuating to liver parenchyma in the early acquisitions and tend to become progressively isoattenuating with time.
- Larger cavities communicating with sinusoids display the same attenuation of blood vessels, whereas thrombosed cavities have the same appearance as nonenhancing nodules.
- The signal intensities of the lesions on MR examination largely depend on the age and status of the blood component.
- On T2-weighted sequences, peliotic lesions are usually hyperintense to liver parenchyma with multiple foci of high signal, likely attributable to hemorrhagic necrosis
- On T1-weighted sequences, the lesions are hypointense because of the presence of subacute blood, although isointense and hyperintense foci are also described in the literature.
- On T1-weighted images after contrast material injection, peliotic lesions usually show enhancement. Similar to CT, the enhancement is typically centrifugal (from the center to the periphery of the lesion).
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 References for Peliosis hepatis
- Iannaccone, Riccardo, Federle, Michael P., Brancatelli, Giuseppe, Matsui, Osamu, Fishman, Elliot K., Narra, Vamsidar R., Grazioli, Luigi, McCarthy, Shirley M., Piacentini, Francesca, Maruzzelli, Luigi, Passariello, Roberto, Vilgrain, Valerie. Peliosis Hepatis: Spectrum of Imaging Findings. Am. J. Roentgenol. 2006 187: W43-52.