Hypereosinophilic syndrome: imaging findings in patients with hepatic involvement.

OBJECTIVE: Hypereosinophilic syndrome (eosinophilia without demonstrable cause) commonly involves eosinophilic infiltration of the liver and spleen, but few reports have described the imaging findings. Accordingly, we reviewed the imaging findings in five patients with this syndrome in whom the liver was involved.
MATERIALS AND METHODS: Five patients who had hypereosinophilic syndrome with hepatic involvement were included in the study. The diagnosis of hepatic involvement was based on pathologic proof in two patients and on imaging and laboratory findings in the other three. Histologic examination of the hepatic lesions showed extensive eosinophilic infiltration in two patients and centrilobular necrosis in one. All patients had chest radiography, barium studies of the gastrointestinal tract, abdominal CT, and sonography. Four patients had hepatosplenic scintigraphy. All patients were followed up for 4-24 months.
RESULTS: All patients had mild to marked hepatomegaly with multiple focal lesions. Focal lesions were detected on sonograms in three patients, on CT scans in four, and on scintigrams in three. On sonograms, the lesions were usually small (less than 2 cm in diameter), sharply or poorly defined nodules with varied echogenicity scattered throughout the liver. The lesions were hypodense with poorly defined margins on CT scans and appeared as variably sized areas of decreased radionuclide uptake on scintigrams. For each patient, the number, size, and shape of the lesions varied considerably from one imaging study to another. On follow-up studies 2-6 months after treatment, the appearance of the liver was normal. Other radiologic findings included transient pulmonary infiltrates (two patients), mild cardiomegaly (one patient), and mild lymphadenopathy (three patients).
CONCLUSION: Hypereosinophilic syndrome is a cause of focal hepatic lesions seen on sonograms, CT scans, or scintigrams. The lesions are characterized by the varied appearance on the different types of images and the disappearance of the lesions with treatment.