"Solitary" necrotic nodule of the liver: an enigmatic entity mimicking malignancy.

Aim: The aim of the study is to further investigate the clinicopathological features of solitary necrotic nodules.

Material and methods: Twenty-three archived cases of solitary necrotic nodule of the liver, which were preoperatively misdiagnosed as liver metastases were studied. The pathological findings were correlated with the clinical data of the patients.

Results: The nodules were solitary in 20 cases and multiple (2) in three cases, and measured from 0.5-1.5 cm in diameter. Twenty-one cases were located in the right lobe of the liver (91.6%) and two in the left lobe (8.69%). Twenty nodules were found in the subcapsular region (86.95%), while three nodules were located within the hepatic parenchyma (13.04%). More then half of our cases (12) were accompanied by extended calcification. Granulomatous tissue resembling "burnt-out" parasitic granulomas was found in three cases.

Conclusions: Solitary necrotic nodules of the liver often mimic malignancy in abdominal imaging. Thus, permanent histopathology of the operative specimen remains the only accurate method of diagnosis. Their pathogenesis is most likely variable, and most reported cases are linked either to a parasitic or a vascular origin. Despite the designation of these lesions as "solitary" they may occasionally be multiple. In addition to the standard histological criteria of solitary necrotic nodules, the relatively small size (15 mm or less) and the frequent presence of calcifications seem to further characterize this enigmatic entity. Solitary necrotic nodule should be included in the differential diagnosis of small liver lesions with extensive necrosis.