Massive localized lymphedema: additional locations and association with hypothyroidism

Area of Science:

• Dermatology
• Pathology
• Endocrinology

Background:

• Massive localized lymphedema (MLL) is a recently described entity affecting morbidly obese patients.
• This report details a second series of MLL cases, expanding on initial findings.

Observation:

• Six adult cases presented with large, long-standing MLL masses in various locations including thigh, scrotum, and abdomen.
• Lesions measured up to 75 cm in diameter and weighed over 12,000 g, with overlying skin showing signs of chronic lymphedema.
• Differential diagnoses included lipoma, cellulitis, and well-differentiated liposarcoma due to the marbled appearance.

Findings:

• Histological examination ruled out liposarcoma, revealing reactive features such as lymphatic vascular ectasia, fibrosis, edema, and ischemic changes like fat necrosis.
• The diagnosis of MLL was established based on these reactive and ischemic findings.

Implications:

• Recognition of MLL is crucial for clinicians and pathologists to prevent misdiagnosis as low-grade liposarcoma.
• Potential contributing factors include lymphatic obstruction by pannus or surgery, with a possible association with hypothyroidism suggested by two cases.