  Citation: Varlas, V.; Neagu, O.; Moga, A.; B ˘ al˘ anescu, R.; Bohiltea, R.; Vladareanu, R.; Balanescu, L. Fetal Pancreatic Hamartoma Associated with Hepatoblastoma—An Unusual Tumor Association. Diagnostics 2022, 12, 758. https://doi.org/10.3390/ diagnostics12030758 Academic Editor: Rute Santos Received: 20 December 2021 Accepted: 17 March 2022 Published: 20 March 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). diagnostics Case Report Fetal Pancreatic Hamartoma Associated with Hepatoblastoma—An Unusual Tumor Association Valentin Varlas 1,2 , Oana Neagu 3 , Andreea Moga 4 , Radu Bălănescu 2,4 , Roxana Bohiltea 1,2, *, Radu Vladareanu 2,5 and Laura Balanescu 2,4 1 Department of Obstetrics and Gynecology, Filantropia Clinical Hospital, 011171 Bucharest, Romania; valentin.varlas@umfcd.ro 2 Faculty of General Medicine, “Carol Davila” University of Medicine and Pharmacy, 37 Dionisie Lupu St., 020021 Bucharest, Romania; radu.balanescu@umfcd.ro (R.B.); vladareanu@gmail.com (R.V.); laura.balanescu@umfcd.ro (L.B.) 3 Department of Anatomopathology, “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania; oana.neagu@yahoo.com 4 Department of Pediatric Surgery, Children Emergency Hospital “Grigore Alexandrescu”, 011743 Bucharest, Romania; alecsandra.moga@drd.umfcd.ro 5 Department of Obstetrics and Gynecology, Elias Clinical Hospital, 011461 Bucharest, Romania * Correspondence: dr.bohiltea@gmail.com Abstract: Abdominal tumor masses are a very rare disease in the fetus. The authors present the first reported case of neonatal multicystic adenomatoid hamartoma of the pancreas associated with well-differentiated fetal epithelial subtype hepatoblastoma and reveal clinical, histologic, and imag- istic aspects. Case presentation: A 36-week-old female newborn in whom a 25-week ultrasound showed a relatively homogeneous pancreatic echogenic mass (34 × 30 × 55 mm) with compres- sion of the inferior vena cava and retrograde dilation. Postnatal CT showed a giant pancreatic tumor mass (113 × 70 × 60 mm), with areas enhancing contrast and cystic/necrotic areas and a hypodense, hypocaptive nodule of 8 × 6 mm located at segment IV of the liver; thrombosis of the subhepatic segment of the inferior vena cava and both renal veins. Histopathological and immunohis- tochemical studies confirmed the diagnosis of multicystic pancreatic adenomatoid hamartoma and well-differentiated fetal epithelial subtype hepatoblastoma. Conclusions: Pancreatic hamartoma can be difficult to diagnose (especially prenatal), with or without nonspecific symptoms. The synchronous presence of hepatoblastoma complicated the therapeutic conduct and prognosis of this case, with the diagnosis being confirmed histopathologically and immunohistochemically after liver biopsy. Keywords: fetal abdominal mass; fetal pancreatic tumors; hamartoma; hepatoblastoma; ultrasonog- raphy; fetal inferior vena cava anomalies 1. Introduction Fetal intra-abdominal complex tumors are extremely rare and are benign in most cases. Likewise, tumors of the fetal pancreas are extremely rare and mainly represent congenital islet cell adenoma [1]. The authors report a unique case of pancreatic hamartoma associated with a hepatoblastoma in a 36-week-old newborn who presented an abdominal mass. A literature review did not identify any previous reports of the association of these conditions in a newborn. The case is all the more interesting as suspicion of the pancreatic tumor in the fetus was raised by imagistic findings from the 25th week of pregnancy. The prevalence of congenital tumors is 7.2 per 100,000 live births [2]. The incidence of fetal neoplasms that can be detected by ultrasound is 36.5 per million live births, according to the study by Solt et al. [3]. Hepatoblastoma is the most common liver malignancy, with an increased incidence in the first year of life, representing 11.2 cases per 1 million [4]. The incidence in Europe is 1.2 per million [5] and in the USA between 0.8–1.5 per million [6], with over 90% Diagnostics 2022, 12, 758. https://doi.org/10.3390/diagnostics12030758 https://www.mdpi.com/journal/diagnostics