Primary congenital lymphedema with atypical unilateral presentation: a review of the literature and case illustration

Background: Primary congenital lymphedema (PCL) characteristically presents as symmetrical, bilateral lower extremity edema. Atypical unilateral phenotypes, particularly those featuring discordant digit involvement across upper and lower limbs, are exceedingly rare clinical entities presenting unique diagnostic and management challenges. Case Presentation: We present a 23-year-old female with an atypical unilateral PCL variant, characterized by asymmetric localized swelling of the left upper and lower extremities that has been present since birth. Distinctively, the edema involved the upper limb digits while sparing the lower limb digits. The chronic course was complicated by recurrent non-healing ulcers starting at age 18, culminating in wet gangrene and subsequent amputation of the left fifth digit at age 23. Recent evaluation revealed recurrent left-hand ulcers. Magnetic resonance imaging (MRI) of both extremities revealed extensive lobulated subcutaneous T2-hyperintense lesions without deep tissue infiltration. Lymphoscintigraphy confirmed congenital lymphatic dysplasia. Active ulcers were successfully treated with collagen dressings and a long-term regimen of combined decongestive and heat therapy was advised. Literature Review: A literature review was conducted to differentiate classic PCL presentations with rare ipsilateral variants, evaluating the diagnostic utility of multi-extremity MRI and the long-term efficacy of combined conservative wound and lymphedema management. Conclusion: This case illustrates a severe, atypical PCL phenotype, emphasizing the necessity of multi-modal imaging for precise anatomical mapping and demonstrating the clinical importance of collagen dressings and heat therapy for chronic, limb-threatening lymphatic complications.