Lymphatic Filariasis

Lymphatic filariasis is a helminthic disease caused by the filarial nematodes Wuchereria bancrofti, Brugia malayi and Brugia timori, transmitted to humans by several mosquito genera, including Anopheles, Aedes, Culex and Mansoni. Its transmission has been documented throughout Africa, Southeast Asia and the Pacific, and in focal areas in the Caribbean, South America, and the Middle East. The disease, characterized by a long-term infection, can affect the lymphatic system, leading to clinical features that include chronic limb lymphedema (progressing to elephantiasis in severe cases) or to lymphoedema of the scrotum (hydrocele). Since 2000, the prevalence of this disabling disease declined to approximately 51 million individuals in 2017, thanks to the prevention and control programmes in place.

In addition to the most frequent clinically reported presentations of lower limb lymphedema and hydrocele, filariae were detected in cytological smears from various body sites in malignant lesions. Among diseases co-occurring with lymphatic filariasis, lymphangiosarcoma was described in occasional case reports. The true incidence of lymphangiosarcoma in chronic filariasis is unknown, and it is likely affected by under-reporting bias in endemic regions.

The development of vascular oncogenesis in patients with lymphatic filariasis could thus be secondary mainly to lymph stasis, which impairs immune cell migration, local immune response and angiogenesis, whenever a failure of the local mechanisms of immune surveillance for malignant cells occurs.

Lymphangiosarcoma is usually diagnosed in all patients after a long history of chronic lymphatic filariasis (approximately 20 years). The skin lesions can be present from 2 to 24 months before the diagnosis, frequently with a concomitant lymphadenopathy. Pain, anaemia secondary to bleeding and an overlapping infection can also be present. The majority of lesions described are ulcerative, bleed and have a foul smell. Biopsy is always needed to carry out differential diagnosis.

Major amputation above or below the knee is a frequently performed treatment in patients with lymphangiosarcoma that is diagnosed on chronic lymphatic filariasis. Disability due to the demolitive procedure, recurrent lesions on amputation stump and recurrent metastasis were reported at follow-up.

Patients with chronic lymphatic filariasis should be monitored for the occurrence of skin ulcers and promptly investigated on. Further studies are needed to better define this combination of co-occurrent condition.