J Clin Pathol. 2009 Sep

Manduch M, Oliveira AM, Nascimento AG, Folpe AL.
Department of Laboratory Medicine and Pathology, Mayo Clinic,
Rochester, Minnesota 55905, USA.

BACKGROUND: Massive localised lymphoedema (MLL) is a rare, relatively
recently described pseudosarcoma most often occurring in morbidly
obese patients. AIM: To perform a retrospective review of all cases
diagnosed as MLL.

METHODS AND RESULTS: Clinical information was obtained. 22 morbidly
obese adults (mean patient weight 186 kg) presented with unilateral,
large soft tissue lesions of longstanding duration. Most lesions
involved the thigh, but also occurred in the posterior calf and lower
leg. Clinically, most lesions were regarded as representing benign
processes, including pedunculated lipoma, lymphocoele or recurrent
cellulites, although soft tissue sarcoma was also suspected in two
cases. Grossly, all masses showed markedly thickened skin with a
"cobblestone" appearance, and were ill-defined, unencapsulated,
lobulate, and very large (mean size 31 cm, range 15-61.5 cm, mean
weight 3386 g, range 1133-10,800 g). Histologically, all 22 cases
showed striking dermal fibrosis, expansion of the fibrous septa
between fat lobules with increased numbers of stromal fibroblasts,
lymphatic proliferation and lymphangiectasia. Multinucleated
fibroblastic cells, marked vascular proliferation, moderate stromal
cellularity and fascicular growth raised concern among referring
pathologists for atypical lipomatous tumour/well differentiated
liposarcoma, angiosarcoma, and a fibroblastic neoplasm such as
fibromatosis in 10, 2 and 1 case, respectively.

CONCLUSION: The diagnosis of MLL continues to be challenging, in
particular for pathologists. Awareness of this entity, clinical
correlation and gross pathological correlation are essential in the
separation of this distinctive pseudosarcoma from its various
morphological mimics.

British Medical Journal

http://jcp.bmj.com/cgi/content/full/62/9/808