Hepatic adrenal rest tumor: Diagnostic pitfall and proposed algorithms to prevent misdiagnosis as lipid‐rich hepatocellular carcinoma

Abstract

We present a case of adrenal rest tumor of the liver in which differential diagnosis from lipid rich-hepatocellular carcinoma (HCC) was challenging. The patient was a 50-year-old woman in whom a 3-cm tumorous mass was discovered in segment 7 of the liver during computed tomography evaluation of a uterine leiomyoma. The preoperative diagnosis was HCC, and subsegmental liver resection was performed. The tumor appeared as a well-demarcated golden yellow nodule consisting of clear or partially eosinophilic cells arranged in a trabecular pattern. The initial impression of this lesion was that of clear cell type or lipid-rich type HCC because it stained positive for Hep Par1, but negative for arginase-1 and positive for CD56 which is one of the neuroendocrine markers. The lesion also stained positive for SF-1 and 3β-HSD, both of which are markers of adrenocortical tissue. The final diagnosis was hepatic adrenal rest tumor. Hepatic adrenal rest tumor should be considered in the differential diagnosis of segment 7 tumor. A diagnostic algorithm that includes immunohistochemical staining for CD56 and arginase-1 is to rule out the possibility of lipid-rich HCC.

Adrenal Rest Tumor of the Liver Preoperatively Diagnosed as Hepatocellular Carcinoma

“…The findings consist of cord-like arrangements of round to polygonal, pale, lipid-rich cells separated by vascular channels or bands of collagen [5]. However, Sugiyama reported that it is difficult to distinguish between hepatic adrenal rest tumor and HCC on the basis of histologic analysis alone [11]. Immunohistochemistry showed the tumor cells to be weakly stained for Hep-per-1, which can be considered a specific marker for HCC.…”

“…Adrenal rest tumors are collections of aberrantly located adrenocortical tissues, and they rarely occur in the liver. We searched in the PubMed database and found only nine case reports of hepatic adrenal rest tumor [3–11]. Two cases were described to be associated with endocrine abnormalities and malignant histological feature [3, 4].…”

“…Two cases were described to be associated with endocrine abnormalities and malignant histological feature [3, 4]. Seven cases were nonfunctional, presenting as incidental findings [5–11]. These seven tumors were discovered in the posterosuperior subsegment of the right hepatic lobe (segment 7), and HCC could not be excluded preoperatively.…”

Pheochromocytoma arising from an ectopic adrenal tissue in multiple endocrine neoplasia type 2A

“…These reports indicate that ectopic adrenal tissue usually contains only the adrenal cortex and is found accidentally. Additionally, organs originating from the mesoderm, such as the kidney and liver, are also frequent sites of ectopic adrenal tissue (3). In these cases, it is difficult to distinguish malignant tumors arising from these organs from ectopic adrenal tissue without histological assessment, and ectopic adrenal tissue contains only the adrenal cortex (3).…”

“…Most ectopic adrenal tissue is asymptomatic and found incidentally during operations such as inguinal hernia repair (2). However, ectopic adrenal tissue and malignant tumors can be difficult to distinguish if located in renal or hepatic parenchyma (3). Some case reports have described functional adrenocortical adenoma or adrenocortical carcinoma arising from ectopic adrenal tissue.…”