An infantile case of infiltrating lipoma in the buttock

Congenital infiltrating lipoma of the upper limb in a patient with von Willebrand disease

Infiltrating lipoma is a rare variety of lipoma, characterized by an infiltration of the adipose tissue of the muscles. Infiltrating lipomas are usually classified in two groups: intermuscular infiltrating lipoma and intramuscular infiltrating lipoma. Most are acquired, and they usually appear in middle-aged individuals. Exceptionally, they are congenital. In such cases they are not related to other diseases. We report an 8-year-old boy with a congenital infiltrating lipoma of the upper limb and von Willebrand disease. Both diseases are linked to an alteration in chromosome 12, but this clinical association seems to be random rather than causal.

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

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.

Case report 814: Fibrolipoma of the median nerve

A case of fibrolipoma of the median nerve was described. Peripheral nerve tumors of the upper extremity are very rare. Within this group of tumors, the fibrolipoma is an exceedingly uncommon entity. It was first described in 1953, and to date less than 100 cases have been described. The purpose of this report was to point out a characteristic sign of fibrolipoma, which in our opinion allows distinction on CT and MRI between fibrolipoma and the other peripheral nerve and fatty soft tissue tumors.