Clinicopathologic features of 6 cases of segmental atrophy of liver and review of the literature.

Segmental atrophy (SA) of the liver is a rare and frequently under-recognized condition that can lead to the formation of pseudotumors, posing significant challenges in both clinical and imaging diagnoses. To date, this disease has been infrequently reported in the literature. To elucidate the clinicopathological characteristics of SA and enhance clinicians' understanding, we collected clinical and pathological data from 6 cases of SA and summarized the clinical information and pathological features of 22 previously reported SA patients. Among all cases, 19 patients were female and 9 were male, with a median age of 60 years. Lesion sizes varied widely, ranging from 1.5 to 10.5 cm. 17 patients exhibited notable right upper quadrant abdominal pain. Histological examination revealed a sequence of changes: early-stage lesions exhibited varying degrees of hepatic parenchyma collapse, brisk bile ductular proliferation, and extensive infiltration of chronic inflammatory cells, accompanied by very mild elastosis. In subsequent stages, the lesions exhibited reduced bile duct proliferation and inflammatory response alongside a notable increase in elastic fibers. Advanced-stage lesions presented with extensive elastic fiber deposition, occasionally interspersed with scattered islands of hepatocytes, and the terminal phase manifested as dense fibrotic nodules. Abnormally thick-walled blood vessels were identified in nearly all cases (n = 25), and bile duct cysts were observed in some cases (n = 11). In summary, SA primarily affects middle-aged individuals, with a female predominance, and presents with nonspecific clinical symptoms, predominantly right upper quadrant pain. Pathologically, it displays a continuous histomorphological spectrum. Elastic fiber staining has proven beneficial for both diagnosis and differential diagnosis of this condition. Proficiency in recognizing its diverse morphological features is essential for accurate diagnosis.