MR imaging of benign fatty tumors in children: report of four cases and review of the literature

Abstract

This study correlates the magnetic resonance imaging characteristics with the pathologic findings in rare benign fatty soft tissue tumors in four children. A review of the literature is presented. Two cases of infiltrating lipoma displayed bright signal on both T1- and T2-weighted images, similar to that observed in subcutaneous fat. Histological study revealed extensive muscle infiltration by mature fat, with some areas of total fatty replacement. The case of facial lipomatosis revealed an extensive process of fatty invasion of adjacent soft tissue and osseous deformity by mass effect of the tumor. This lesion was bright on T1- and T2-weighted images. Histopathologic examination showed widespread invasion of squamous mucosa and skeletal muscle. The single case of lipoblastoma involved the presacral region and right buttock. This lesion, although bright on both T1 and T2 weighting, was relatively hypointense to subcutaneous fat on T1. Microscopic examination revealed a well-encapsulated fatty mass made up of cells ranging from lipoblasts to mature lipocytes. In childhood, when fatty lesions are almost always benign, a morphologic characterization by magnetic resonance may be sufficient basis on which to make critical therapeutic judgements.

Chest wall lipoblastoma in a seven-month-old girl: A case report

“…Reports of MRI in children with lipoblastoma, however, are limited. 11 Histopathologically, it differs from the myxoid liposarcomas by its characteristically lobular structure, devoid of pleomorphic cells with hyperchromatic nuclei or giant cells. In recently conducted cytogenetical studies, an anomaly in chromosome 8 q has been reported in lipoblastoma cases.…”

Fine Needle Aspiration Diagnosis of Lipoblastoma of the Parotid Region

“…These singular findings correlate with immature and mature adipose, myxoid areas and areas of cystic degeneration. [27][28][29][30] Thus, MRI seems to be a reliable radiologic tool. Lipoblastoma must be suspected in a child < 3 years of age with a predominantly fatty, nonhomogeneous, soft tissue mass on MRI.…”

Soft Tissue Masses

“…The presenting symptoms relate to the size and location of the mass, but the mass itself is not painful [ 42 ]. Left alone, they mature into a benign lipoma [ 43 ]. Histologic evaluation reveals a spectrum of fat cells in various stages of maturation, ranging from lipoblasts to mature adipocytes, embedded in a variable amount of myxoid stroma; the myxoid component is anecdotally more prominent in very young patients [ 42 ].…”