Purpose: Hibernomas are rare benign soft tissue tumors composed of brown fatty tissue. Retroperiotoneal
localization is an unusual site for this tumor and only few cases of this entity have
been published in the literature. The purpose of this presentation is to reveal the
radiologic findings of this soft tissue tumor with histologic correlation.
Methods and Materials: A 13-year-old male was admitted to our clinic with 1 month history of periumblical
abdominal pain, weight loss (6kg in 1 month) and sweating. There was no significant
finding in physical examination. Abdominal X-Ray graphy, ultrasound(US) and abdominal-pelvic
computarized tomography(CT) examinations were performed.
Results: There was no significant finding in plain abdominal radiography. Abdominal US revealed
a 6×5 x3cm, well-circumferenced, hyperechoic, preaortic mass encasing celiac truncus,
compressing aorta and splenic vein minimally. The proximal segment of superior mesenteric
arter(SMA) was in close relation with the mass. Doppler US examination showed no stenotic
finding in SMA or celiac artery. In CT and US there was no fatty plain between the
mass and the pancreatic corpus. Be cause of the relationship with the main arterial
vessels, the mass could not totally excited. Histologically, adiposits that belong
to brown fatty tissue with centrally localized nucleus were seen and hibernoma was
revealed as final diagnosis.
Conclusions: Hibernomas are asymptomatic, slow-growing tumors occuring in the anatomical sites
where brown fatty tissue was found during fetal life such as inter-scapular region
or thigh, retroperitoneal localization is exremelly rare. Although minority of retroperitoneal
adipose tumors show histological signs of benignity, retroperitoneal hibernomas are
benign in nature without evidence of metastasis or any signs of recurrence after surgery.
Therefore hibernoma should be included in the differential diagnosis of retroperitoneal
soft tissue tumors and total surgical excision is the remarkable choice for their
treatment.
