An audit of metastatic tumors to the liver highlighting the spectrum of differential diagnosis: A retrospective study from a tertiary cancer center in North India

Abstract

ABSTRACT Background: Space-occupying lesions of the liver can broadly be divided into benign and malignant and further as primary and metastatic lesions. Among the malignant lesions of the liver, metastatic lesions of unknown primary origin present as one of the most common clinical dilemmas. Objectives: The primary objective was to study the histomorphological and immunohistochemical profiles of the secondaries to the liver. The secondary objective was to outline an approach toward an accurate diagnosis of the primary site and exclusion of the close differentials, especially in the case of round-cell tumors and spindle cell lesions. Materials and Methods: This retrospective cross-sectional study was conducted from May 2018 to September 2020 at the Department of Pathology, Homi Bhabha Cancer Hospital and Mahamana Pandit Madan Mohan Malaviya Cancer Center, Varanasi, Uttar Pradesh, India. All patients diagnosed with metastatic liver lesions were studied. The cases were reviewed for histomorphological and immunohistochemical findings, and the data were analyzed using Microsoft Excel. Results: A total of 452 cases were studied, and the mean age was 54.8 ± 13.5 (standard deviation) years with the age ranging from 7 months to 88 years (median, 56; interquartile range, 46-65 years) with female (n = 243, 53.8%) predominance. Adenocarcinomas (n = 302, 66.8%), followed by neuroendocrine lesions (n = 63, 13.9%), were the most common histology, while melanoma (n = 2, 0.4%) was the least common. The common sites of the primary were pancreaticobiliary (n = 231, 51.1%), lung (n = 58, 12.8%), breast (n = 31, 6.9%), and colorectal (n = 20, 4.4%). Less frequent lesions involving the liver, such as spindle cell lesions, lymphomas, melanomas, and germ cell tumors, were also noted. Conclusions: The liver is one of the most common sites of metastasis from various organs. Adenocarcinoma is the most common tumor, amid which metastasis from the pancreaticobiliary tract is the most common site of primary. Hence, a stepwise approach of immunohistochemistry in conjunction with clinicoradiological assessment is necessary for an apt diagnosis and treatment.