Hepatoid differentiation in renal cell carcinoma: a rare histologic pattern with clinical significance

A Giant Hepatoid Carcinoma of the Perirenal Fat With Very High A-Fetoprotein and Vitamin B12 Levels

“…Correlation between hepatoid renal tumors and vitamin B12 elevation is scarcely reported in the literature. 1-4…”

“…Hepatoid adenocarcinoma differentiation requires not only AFP production, but also fulfilling morphological criteria of hepatoid differentiation such as the formation of cords, trabeculae, or small sheets of polygonal cells separated by thin sinusoidal blood vessels or evidence of bile production or bile canalicular formation. 1…”

“…In addition, apart from AFP, all the other hepatoid markers, such as poly-CEA, GPC3, and transaminases, remained within normal levels, in support to the majority of previously reported cases in the literature. 1…”

“…However, there have been less than 10 cases of RCCs producing AFP and less than 5 cases of hepatoid differentiated ectopic renal tumors reported, none of which originated from the perirenal fat. 1-3…”

“…A Giant Hepatoid Carcinoma of the Perirenal Fat With Very High A-Fetoprotein and Vitamin B12 Levels Nikolaos A. Kostakopoulos, MD, PhD 1,2 , Nikolaos D. Karakousis, MD, Msc 3 , Dimitrios Linardoutsos, MD, PhD 1 , Vasilios Argyropoulos, MD, PhD 1 , Panagiotis Kouroupakis, MD, Msc 1 , Stavroula Kastora, MD, PhD 2 , and Athanasios N. Kostakopoulos, MD, PhD 1 Ectopic hepatoid tumors producing A-fetoprotein (AFP) present a rare entity with unfavorable prognosis. Less than 5 cases of hepatoid carcinomas of the kidney are described in the literature; however, our case is the only one originating from the perirenal fat to our best knowledge.…”