Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma with Myxoid Stroma in a Hereditary Retinoblastoma Survivor

Abstract

Atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDL) is an indolent, locally aggressive mesenchymal neoplasm, most often confined to the lower extremities and retroperitoneum and rarely identified in the orbit. Diagnosis of ALT/WDL can be challenging due to its frequent morphologic overlap with benign adipose lesions and other more aggressive liposarcoma subtypes, including myxoid liposarcoma. We describe a 26-year-old female with a history of hereditary retinoblastoma and external-beam radiotherapy to the orbit, who developed orbital liposarcoma. Although initial morphologic assessment raised the consideration of myxoid liposarcoma, subsequent fluorescein in situ hybridization studies demonstrated MDM2 and DDIT3 coamplification without DDIT3 rearrangement, supporting the diagnosis of ALT/WDL with myxoid stroma. The literature review of previously reported orbital myxoid liposarcomas revealed a morphologic overlap of documented tumors with ALT/WDL, dedifferentiated liposarcoma, and pleomorphic liposarcoma with myxoid stroma as well as an absence of immunohistochemical and molecular genetic data supportive of the diagnosis of myxoid liposarcoma. This case emphasizes the potential overlap of ALT/WDL with myxoid liposarcoma and the increasing importance of molecular genetic studies in the diagnosis, prognosis, and management of orbital liposarcoma.

Recurrent primary orbital well-differentiated liposarcoma /atypical lipomatous tumor: A rare case report with six-year follow-up

“… 2 So far, less than 70 primary orbital liposarcoma cases have been reported and less than 30 of them have been the WDL/ALT subtype, slightly more than myxoid/round cell type. 5 , 6 , 7 , 8 , 9 , 10 , 11 Although WDL/ALT is considered to have the least potential to metastasize among all subtypes of liposarcomas, local invasion or recurrence have been reported. 2 , 5 , 6 , 11 , 12 Only four of 29 cases in the literature have been followed up for at least six years as in our current case.…”

“… 5 , 6 , 7 , 8 , 9 , 10 , 11 Although WDL/ALT is considered to have the least potential to metastasize among all subtypes of liposarcomas, local invasion or recurrence have been reported. 2 , 5 , 6 , 11 , 12 Only four of 29 cases in the literature have been followed up for at least six years as in our current case. Three out of four of these cases had local recurrence.…”

Editorial for “Differentiation Between Lipomas and Atypical Lipomatous Tumors of the Extremities Using Radiomics”

“…Clearly the differential diagnosis between ALT/WDL and lipoma is critical for the determination of the treatment plan and/or resection margin, as an incorrect classification may lead to delayed treatment and increased costs to the patient. Because the benign lipomas and ALTs/WDLs share many histological and molecular features, the discrimination between them can be diagnostically challenging 6,7 . MRI is currently the most common method for the screening and diagnosis of soft tissue tumors.…”

“…In conclusion, the paper introduced a non‐invasive, machine‐learning based radiomics to distinguish between the benign lipomas and ALTs, a challenging topic in clinical practice due to the frequent morphologic overlap between them 7 . The method developed in the paper has great potential to assist radiologists in distinguishing lipomas from ALTs.…”

“…Because the benign lipomas and ALTs/WDLs share many histological and molecular features, the discrimination between them can be diagnostically challenging. 6,7 MRI is currently the most common method for the screening and diagnosis of soft tissue tumors. However, the MRI features of ALT/WDL are similar to those of lipoma, usually having relatively homogenous MR signal equivalent to normal fat, and generally insensitive to gadolinium administration, making the discrimination using MRI directly difficult.…”