[83] Massive Localized Lymphedema: A Series of 8 Cases

J Rock, W Wang, WQ Zhao, H Iwenofu, G He. Ohio State University Medical Center, Columbus, OH

Background: Massive localized lymphedema (MLL) is a benign lesion that clinically and morphologically may simulate well-differentiated liposarcoma. We report a series of 8 cases of MLL and analyze its clinical, morphologic, and immunohistochemical features.
Design: Eight cases from 7 patients were diagnosed MLL and treated in our institution between 2002 and 2008. Clinical history and imaging studies were collected. Surgical specimens were grossly and microscopically examined.
Results: MLL was diagnosed in 7 patients, 5 males and 2 females, aged 23 to 69 years (mean 44). All patients were obese, 3 had hypothyroidism and heart disease, 1 diabetes, and 1 trauma with recurrent lesion. Five MLL occurred at the medial right thigh, 2 (male) at the pubic area. All MLL were pre-surgically diagnosed by clinician except one termed suspicious for liposarcoma by radiologist. Grossly, all specimens (1.5-25.7 kg) showed thickened peau d'orange-like skin with tan-yellow, lobulated, focally fibrotic, and markedly edematous cut surfaces. No necrosis or hemorrhage was noted. Histologically, the skin was thickened with mild hyperkeratosis and edematous or hyalinized dermis. The dermis and subcutis showed numerous small to medium-sized, irregularly shaped lymphatic vessels and small, thick-walled blood vessels surrounded by scattered to dense lymphocytes. One case showed focal dense follicular lymphoid aggregates with germinal centers. The stroma was extremely hypocellular and edematous. Mildly hyperchromatic fibroblasts were present in the stroma or fibrotic septae, but no atypia nor mitotic figures were seen. Lymphocytes were mainly CD4+ T cells, with few CD8+ T cells and B cells, while the case with dense lymphoid follicles showed both dense T and B cells. D2-40 highlighted all the lymphatic channels in dermis/subcutis, while endothelial and smooth muscle markers were positive on blood vessels (less on lymphatic vessels). CD34 was also focally positive on stromal fibroblastic cells. Bcl-2 was positive on some lymphocytes, but negative on stromal cells. Cytokeratin, WT-1, CD99, p53, S-100, and CD68 were all negative. Ki-67 was negative or less than 2% in stromal cell nuclei.
Conclusions: MLL is a benign, reactive, superficial pseudoneoplastic lesion seen in obese patients, displaying marked edema of the dermis and subcutis, numerous distended lymphatic vessels, and small-caliber, round, thick-walled blood vessels often surrounded by infiltrates of T lymphocytes. Lack of nuclear atypia, atypical mitotic figures, and lipoblasts differentiate this lesion from well-differentiated liposarcoma.
Category: Bone & Soft Tissue

Monday, March 9, 2009 1:00 PM

Poster Session II # 3, Monday Afternoon